TYPICAL FORMS AND SPECIAL ENDS IN CREATION BY REV. JAMES M'COSH, LL.D., FB0FEB80B OF LOGIC AND METAPHYSICS IN THE QITEEN's tmiVEESITY IN IBKLAND ; AirrnoB op "the method of the divine goveenment, PHYSICAL AND MOEAL," ETC. ; AND GEORGE DICKIE, A.M., M.D., PB0FE880K OF NATCTKAL II18T0KY IN THE QUEEN'S TTNITEESITY IN lEELAND; AND AUTHOE OF A NHMBEE OF PAPEB8 ON ZOOLOGY AND liOTANY. TTnOS KAI TEA02. NEW YORK: KOBEIIT CARTER & BROTHERS, No. 281 IS ]{ O A D W A Y . 1856. STEREOTYPED BY PRINTED BT THOMASB. SMITH, K.O.JENKINS, 82 & »1 Beekman St., N. Y. 24 Frankfort St. * • « • • • » > . CO 2>'0 Mist c^ ADVERTISEMENT CQ UJ BY U. THE AMERICAN PUBLISHER. s^ The principles now fully explained and illustrated in this work ^ were first brought before the public in an article on Typical 0^ Forms by Dr. McCosh in the " North British Review" for August ^ 1851. Mr. Hugh Miller wrote a lengthened notice of that article, describing it as : " An article at once the most suggestive and ingenious which we have almost ever perused. The typology of Scripture has formed the subject of Kj many a volume and many a discourse. It is one of the most obvious and 5 rudimental truths of the theologian, that he who spoke in parable and '~ allegory when he walked the earth in the flesh, spoke in his previous rev- '* elation ere he had yet put on the nature of man, by type and sjnnbol; and that there is thus a palpable unity of style maintained between God in [^ the Old and God in the New Testament. Nay, some of the profounder ^ theologians went further than this; and works such as the "Analogy" of Butler may be regarded in one point of view as critical Essays, written to estabhsh a yet further identity between the style of Deity in Revelation and in Nature. "All things are double one against another," said the >• wise son of Sirach ; and the celebrated " Treatise" of the most philosophic J of English bishops may bo deemed simply an expansion of the idea. Butler 5 set himself to seek in the natural world the " double" of the rovclatious of C the spiritual one, and to argue from the existence and fitness of the natural type the authenticity and genuineness of the spiritual anti-typo. Such, in short, seems to be the principle of his "Analogy." It has, however, been reserved for our own times, and hitherto at least for a class of men not much disposed to conciliate the assertors of the popular theology, whether at home or abroad — in Protestant or in Popisli countries — to find in Nature analogies wliich, though they tiiemselves have failed to apply tlieni, .seem to reach further than even those of Butler ; and which, wo can liavo little doubt, will at no distant date form the staple facts of a department of theology still very meagerly rfproseutcd in our literature, and internierliate in its place and character between the Natural Theology of the Philoso- e c 3 ADVERTISEMENT. phers and the Dogmatic Theology of the Divines. The article in the " North British" on Typical Forms is a vigorous contribution to this middle depart- ment of theology, which, like a central area left unbuUt in a street after the completion of the erections on both sides, seems so necessary to the union of the contiguous fabrics, and to the design of the whole ; and all that its perusal leaves us to regret is, that its accomplished author, in whom the reader will, we believe, recognize a most original thinker — a man already well known in the ethical field, both in our own country and America — should not have expanded it into a volume. But in the special field which he has chosen he need not greatly fear a competitor. The sub- ject is one, too, on which thought ripens slowly ; for, like the agricultural produce of a new colony, it has all to be raised from the seed ; and the deeply interesting, but comparatively brief article of the reviewer, will, we can not doubt, be yet expanded into a separate treatise, which will prove none the less fresh, and all the more soliii, from the circumstance that it should have appeared as an article first." Since the time when the article referred to was written, Dr. McCosh, in conjunction with Dr. Dickie, has been prosecuting the subject, and the two have Laid a number of their scientific observations before various learned societies, such as the Bo' tanical Society of Edinburg, the Natural History Society of Belfast, and the British Association for the Promotion of Science at its meetinofs in 1852 and 1854. Summaries of these have appeared in the Transactions of the Botanical Society of Edin- burgh in the Annals of Natural History, in the proceedings of the British Association, and in the Edinburgh New Philosophi- cal Journal. They were referred to by his Grace the Duke of Argyle, the President of the British Association, in his open- ing address in September last in the following language : " In physiology, what is the meaning of that great law of adherence to type and pattern, standing behind, as it were, and in reserve, of that other law by which organic structures are specially adapted to special modes of life ? What is the relation between these two laws ; and can any light be cast upon it derived from the history of extinct forms, or from the condi- tions to which we find that existing forms are subject ? In vegetable phy- siology do the same or similar laws prevail, or can we trace others, such as these on the relations between structure, form, and color, of which clear indications have already been established in communications lately made to this Association by Dr. McCosh and Dr. Dickie of Belfast." CONTENTS. BOOK FIRST. PRINCIPLES OF GENERAL ORDER AXB SPECIAL ADAPTATION. CHAPTER I. NATURE OF THE ORDER PREVAILING IN THE MATERIAL WORLD. PAGE Sect. I. — Principles which seem to run through tho Structure of the Cosmos, ...... I Sect. II. — Analysis of the Order in Nature, ... 10 CHAPTER II. nature op the special adaptations in the MATERIAL WORLD. Sect. I. — Need of Special Adjustments in order to the Beneficent Operation of the Forces of Nature, . . . .SO Sect. II. — The Adjustments are designed, and not Casual. — Na- ture of Chance, ..... 39 Sect. III. — Tho Obviousness and Completeness of the Special Adaptations, . . . . . .56 BOOK SECOND. CO-ORDINATED SERIES OF FACTS, GIVING INDICATIONS OF COM- BINED ORDER AND ADAPTATION TIIKOUGUOUT THE VARIOUS KINGDOMS OF NATURE. CHAPTER I. the MINUTE STRUCTURE OF PLANTS AND ANIMALS. Sect. I.— Order in the Structure of the Cell, ... 69 Sect. II.— Special Modifications of the Coll, . . .71 VI CONTENTS. CHAPTER II. THE FORMS OF PLANTS. PAGE Sect. I. — ^Traces of Order in the Organs of Plants, . . 81 Sect. II. — Traces of Special Adaptation in the Organs of the Plant, 130 CHAPTER III. THE COLOURS OF PLANTS. Sect. I. — The Relation of Form and Colour in the Flower, 146 Sect. II. — Adaptation of the Colours of Plants to the Natural Tastes of Man, ..... 152 CHAPTER IV. THE VERTEBRATE SKELETON. Sect. I. — The Homologies and Homotypes of the Vertebrate Skeleton, ...... 175 Sect. II. — Special Adaptations in the Structure of the Skeleton, . 192 CHAPTER V. teeth. Sect. I. — Order in the Number, Form, and Structure of Teeth, 213 Sect. II. — Special Adaptations in the Number, Form, and Struc- ture of Teeth, . . . . .215 CHAPTER VI. ilOLLUSCA. Sect. I. — Typical Forms of MoUusca, .... 223 Sect, n. — Modifications of the Archetype Mollusc, . . 227 CHAPTER VII. ARTICULATA. Sect. I. — Homotypal Rings and Appendages, . . . 233 Sect. II. — Special Modifications of Rings and Appendages, 2?.7 CONTENTS. Til CHAPTER VIII. RADIATA. PAGE Sect. I. — Typical Forms of Radiata, . . . .267 Sect. II. — Adaptation of Radiate Types to Mode of Life, . . 271 CHAPTER IX. Nervous, vascular, and muscular systems, . . . 280 CHAPTER X. Community of plan, with special modifications, in the development op organized beings, . . . 299 CHAPTER XL GEOLOGY. Sect. I. — Traces of Plan in Fossil Remains, . . . 309 Sect. II. — Adaptations of Fossil Organisms to their Functions. — Preparations for Man, .... 333 CHAPTER XII. INORGANIC objects ON THE EARTH'S SURFACE. Sect. I. — Crystalline Forms and Cliemical Proportions, . . 354 Sect. II. — Adaptations of Inorganic Objects to Animals and Plants — Physical Geograpliy, .... 369 CHAPTER XIII. THE HEAVENS. Sect. I. — Order in the Movements of the Heavenly Bodies, . 388 Sect. II. — Special Adjimtments needed in order to tho ITarmony of Cosmical Bodies, . . . • • 401 Vm CONTENTS. BOOK THIRD. THE INTE«PEETATION OF THE FACTS, CHAPTER I. FAOS The akoument from combined order and adaptation, . 420 CHAPTER II. CORRESPONDENCE BETWEEN THE LAWS OF THE MATERIAL "WORLD AND THE FACULTIES OF THE HUMAN MIND. Sect. I. — The Fantasy, or Imaging Power of the Mind, . . 440 Sect. II. — The Faculties which discover Relations (Correlative), . 449 Sect. III. — The Association of Ideas, > . . . 473 Sect. IY. — The .(Esthetic Sentiments, .... 481 Supplementary Section. — Brief Historical and Critical Review of the Theories of the Continental Philosophers as to the Re- lation between the Laws of the Internal and External Worlds, . 492 CHAPTER III. TYPICAL SYSTEMS OF NATURE AND REVELATION. Sect. I.-^Old Testament Types, ..... 504 Sect. II. — Typical Numbers of Scripture, . . . 518 Sect. III. — ^Typical System of the New Testament, . . 525 APPENDIX. Selected List of Plants, illustrating Associations of Colour, and the Relations of Form and Colour, .... 533 Index, ........ 53T BOOK FIRST. -♦-»-•- CHAPTER I. NATURE OF THE ORDER PREVAILING IN THE MATERIAL WORLD. SECT. I. PRINCIPLES WHICH SEES! TO EUN THROUGU THE STRUCTURE OF THE COS:j^OS. In taking an enlarged view of the constitution of the material universe, so far as it falls under our notice, it may be discovered that attention, at once extensive and minute, is paid to two great principles or methods of procedure. The one is the Pkinciple of Order, or a General Plan, Pattern, or Type, to which every given object is made to conform with more or less precision. The other is the Principle of Special Adaptation, or Particular End, by which each object, while constructed after a general model, is, at the same time, accommo- dated to the situation which it has to occupy, and a pur- pose which it is intended to. serve. These two principles are exhibited in not a few inorganic objects, and they meet in the structure of every plant and every animal. These two principles are characteristic of intelli- gence ; they must ])roceed fnim intelligence, and they are addressed to intelligence. They may both be discovered, though necessarily to a limited extent, in linman work- 1 2 PRINCIPLES BUNNIXG THROUGH manship. When circumstances admit, man deliglits to construct the instruments or utensils which are designed to serve a common purpose after a common plan, even when this is by no means essential to the immediate purpose to be served. 'Each particular piece of dress or article of furniture in a country is commonly fashioned after some general model, so that we are able to guess its use as soon as we cast our eyes upon it. That there is so much of this figure no way fitted to accomphsh a special end, is evident from the circumstance that articles serving the same purpose take — in different ages and nations, and according to the fashion of the place or time — somewhat different forms, all of which are equally convenient. The farmer builds up his grain in stacks, which have all a like contour, and the merchant packs his goods in vessels of equal size and similar shape, or disposes of them in bales of equal weight. It is only when his possessions are so arranged that man can be said to have the command of them. Were his property not so disposed, were his grain gathered into heaps of all sizes and shapes, were his merchandise scattered in every corner of the apartment, the possessor would become bewildered in proportion to the profusion and variety of his wealth. When things are formed or arranged on some plan tacitly agreed on, man can recognize every object at a distance by its physiognomy, and determine its nature and its end without seeing it in use or ope- ration. There are still more frequent and obvious examples in the works of man of the principle of special adap- tation. While there is a general regard, so far as it can be done without immediate inconvenience to the prin- ciple of order, there is a far more constant attention to the other principle. In some cases, indeed, little respect THE MATEEIAL WORLD. 6 can be liad to the general model ; the sole end aimed at is the fitting of the instrument to the purpose which it is meant to serve. In nations low in the scale of civili- zation, and among persons who have to engage in a hard struggle to procure the necessaries of life, the general order is apt to be neglected in the exclusive regard which must be had to immediate utility. In such cir- cumstances, individuals care little how an article be con- structed, provided it serves its practical purpose. But as man's industrial treasures increase, and the number of separate works intended to accomplish similar ends are multiplied, he finds it becoming to institute some systematic arrangement among them, or devise some pattern after which to fashion them. When hard necessity does not forbid, man feels a pleasure in constructing his works upon a general ^lan. Human intelligence delights to employ itself in forming such models. They seem to have a beauty to the eye, or rather to the mind, which contemplates them. If it is a basket that is to be woven, there will commonly be a regularity in the succession of the plaits, and an aiming after some ideal form in the shape of the whole. If it is a water-jug that is to be fashioned, there will be a general attention paid to symjnetry ; not unfrequently there will be graceful and wa\ang lines in the figure which strikes the eye. The dwelling which the indi- vidual erects for his own special accommodation, will commonly be found to have a door, or some other prom- inent o])jcct, in the center, with a balancing of ])illars, windows, or something else that fixes the attention, on the one side and the other. As man advances in the scale of civihzation, and comes to have superfluous wealth and leisure, he pays an increasing attention to symmetry and ornament. In the urns which lie makes to receive 4 PRINCIPLES RUNNING THROUGH the ashes of the dead, in the temples erected by him in honor of the God whom he worships, there is a scrupu- lous regard had to proportion and outline. As wealth accumulates and taste is cultivated, the law of order and ornament comes to he valued for its own sake, and is followed in the construction of every house, and of every article of furniture in that house, in the setting of every jewel, and in the location of every ornament. In most articles of human workmanship we may dis- cover a greater or less attention to both of the principles to which we have referred. The farmer's stacks are all formed after a general mould, but we may observe a departure from it on either side to suit the quantity or quality of the grain. The merchant's shop seems to be regulated by forms or weights, but there is special form or average weight for every separate article. In some objects we see a greater regard to general plan, and in others to special purposes, and this according as persons wish to give a greater prominence at the time to orna- ment or to utility. Now, if this world proceeds from intelligence, and if it is intended to be contemplated by intelligence, it is surely not unreasonable to suppose that there may be traces in it of the same two modes of procedure. In this treatise we hope to be able to show that there are abun- dant illustrations of both, by an induction reaching over all the kingdoms of nature, and extending even into the kingdoms of grace. Both will be found in the theology of nature to point to the same conclusion ; each furnishes its appropriate proof of the existence and wisdom of a Being who hath constructed every thing on a plan, and made it, at the same time, to serve a purpose. The one, as well as the other, will be found in the dispensations of God, in the kingdom of his Son, and point to a most THE MATERIAL WORLD. 5 interesting analogy between nature and revelation. It will be exjiedient to treat of them as so iar different, ^hich tbey really are, but it will be necessary, at the same time, to show, what is equally true, that the two principles are made to correspond the one to the other, that they meet in a higher unity, and that, after all, they are but two aspects — in many respects different indeed — of one Great Truth.* In certain sections of this treatise it is proposed to unfold some of the more striking examples of General Plan. In respect of this order of facts, natural theology can now take a step in advance, in consequence of what has been done of late years in the discovery of homologies by the sciences of comparative anatomy and morjiho- logical botany. But the recent discoveries in regard to the homology of parts can never set aside the old doctrine of the teleology of parts, which affirms that every organ is adapted to a special end. Every organic object is con- structed after a type, (tOtioc,) and is, at the same time, * In order to remove misapprehension, it may be necessary here to estimate how much truth there is in a statement of Professor Owen, who has done so much to illustrate the subject of general order. " By whatever means or instruments man aids or supersedes his natural locomotive organs, such instruments are adapted expressly and immediately to the end proposed. He docs not fetter himi^elf by the trammels of any common type of locomotive instrument, and increase his pains by having to adjust the parts and com- pensate their proportions so as best to perform the end required without deviating from the pattern previously laid down for all. There is no community of plan or structure between the boat and the balloon, between Stephenson's engine and Brunei's tunnelling machinery; a very remote analogy, if any, can be traced between the instruments de- vised by man to travel in the air and on the sea, through the earth or along its surface." (Owen on the Nature of Limbs, p. 9.) There Is truth in the remark hero made, but it Bccms to US to be overstated, and without the necessary corrections. Man does, in many cases, construct the woiks which are to servo a eonmion end upon a common plan. There i.s a model structure for the boat, for the steam-engine, for our houses, and our t/.-mpIes, In which elegance is more or less attended to. But still it Is to bo admitted that the harmonics, the correspondences, the compensations, are fur more numerous and beautiful, both In kind and degree, In the works of God than In the works of man. It Is certain that the union of the two principles is not so frequently attended to in hnmau as in Divine workmanship. Man Is often obliged to sacrlllcc the one to the other, tho Hymmetry to the convenience, or the utility to tho ornament. It is only in the works of Deity that we llnd the two at all times In harmonious operation. 6 PKINCIPLES KUNNING THROUGH made to accomplish a final cause, (ulog.) Throughout the next Book we purpose to exhibit the traces of Greneral Order in one series of sections, and the traces of Special Adaptation in another series of sections, the two being made to run alongside of each other. While both will be illustrated, it wiU be seen, by our adopting this method, that the two are not contradictory, but coin- cident ; that they do not cross, but run parallel to each other. The general conformity to a pattern will be seen to be aU the more curious when contemplated in con- nection with certain singular deviations ; while the special modifications will appear all the more wonderful when exhibited as a departure, and evidently an intentional departure, to efiect a particular end, from a model usually attended to, nay, to some extent attended to, it may be, in the very structure which is thus modified. The de- signed irregularities will thus, by a legitimate reaction, show that the regularities are also designed ; the excep- tions in this case emphatically prove the rule. The nature of the eccentricities demonstrate that, after all, there is a center round which the revolution is per- formed ; the deviations point to a disturbing influence also under the influence c^f law — in much the same way as the deviations of an old planet were shown by living astronomers to point to a previously undiscovered plane- tary body. The nature, the value, and the relation of the two principles, will thus come out to view more strikingly by comparison and contrast when they are placed in juxtaposition. The arguments and illustrations adduced by British writers for the last age or two in behalf of the Divine existence, have been taken almost exclusively from the indications in nature of special adaptation of parts. Hence, when traces were discovered within the last age THE MATERIAL WORLD. 7 of a general pattern, which had no reference to the com- fort of the animal or the functions of the particular plant, the discovery was represented by some as overturning the whole doctrine of final cause ; not a few viewed the new doctrine with suspicion or alarm, as seemingly adverse to religion, while the great body of scientific men did not know what to make of its religious import. The question is thus started, Have not the writers on the theology of nature been of late most unnecessarily nar- rowing and restricting the argument ? We have found it most interesting to notice that the philosophers of ancient Greece and Rome, and not a few of the earlier writers on the subject in our own country, gave it a much wider range, and reckoned that they had found evidence of the existence of God whenever they detected traces of order and ornament. Let us inquire what instruction we can gather on this subject from some of those great luminaries of the ancient world, which, like stars, send their- light down to us through the wide space which intervenes, and serve, like them, to enlarge and rectify our ideas of magnitude, and to keep us from being imduly impressed with the greatness of the near and the present. Plato, in the Fourth Book of the Laws, makes Clinias of Crete, in proving the existence of God from his works, appeal at once to the order and l)eauty of the universe, and does not regard it as at all necessary to dwell on minute instances of adaptation. He refers to the earth, the sun, and all the stars, and to the beautiful arrange- ment of the seasons, divided into months and years, as evidencing that there is a Divine Being.* In the review of the argument in the Twelfth Book, he repeats, that tlic orderly movements of the stars, and other objects, * IJ. X. c. 9, where lie also brings In tho argument from universal consent 8 PRINCIFLES KUNNING THROUGH prove that all things were arranged and adorned, not by matter or necessity, but according to a Divine fore- thought and will. "■•'=■ According to the sublime philosophy of Plato, all things are formed according to unalterable laws or types, which remain unchanged amidst the flux of individual objects, and that because they proceed from eternal ideas, which had been in or before the Divine mind from all eternity. A similar style of argument is adopted in Cicero's Treatise on the Nature of the Gods, the most systematic work on natural theology which has been handed down to us from ancient times. The evidence adduced by Balbus the Stoic, the representative of theism in the dialogue by which the argument is conducted, is derived from four sources : first, from the presages of futurity by gifted men and oracles ; secondly, from the number of things fit and useful ; thirdly, from prodigies ; fourthly, and highest of all, from the equable motions of the heavenly bodies, and from the beauty and order of the sun, moon, and stars, of which the very sight is sufficient to convince us that they are not fortuitous.f Through- out his defence, he dwells on the consenting and conspir- ing motions of the heavenly bodies, on their progressions and other movements, all constant and according to law ; he points to the planets, which are regular in their veiy wanderings ; and shews how, in all this, there is an order and a certain hkeness to art.J When one observes, he says, their defined and equable mot-ions, and all things proceeding in an appointed order, and by a regulated and unchangeable constancy, he is led to understand not only that there is an inhabitant in this celestial and divine dwelling, but a ruler or regulator, and, if we may so * B. xlil. c. 13. t Cic. De Nat. Deor., Lib. ii. c. v. t I'ib- ii- c. vii. ; xs. ; sxxil. THE MATEKIAL WORLD. 9 speak, arcliitect of so great a work and gift.* He speaks of the harmony arising from dissimilar motions ; and after quoting largely from the hymn of Aratus, he says, such order and ornament could not have proceeded from bodies running together hither and tliither, and by accident.f Plutarch derives men's general agreement as to the existence of God, from their observation of the constant order and motion of the stars. J In modern times, we have the same line of argument seized by the profound mind of Newton. Referring to the UNIFORMITY IN THE BODIES OF ANIMALS, he SayS, " It must necessarily be confessed that it has been efl'ected by intelligence and counsel."§ Dr. Samuel Clarke quotes this language, and asks — " In all the greater sjjecies of animals, where was the necessity for the conformity we observe in the Number and Lilvcness of all their prin- cipal members ?"\\ It is very evident that, down to a comparatively late date, writers on natural theism did not confine their proof to a mere adaptation of parts, but that along with this they introduced other considerations, and in parti- cular, the prevalence of general order. It will not be difficult to defend the legitimacy of the con\T[ction which the order and beauty of the universe have produced in un- sopliisticated minds in all ages. In this, as in many other instances, the philosopher will find it to be his delightful office, not to set aside the spontaneous beliefs of mankind, but rather to vindicate and illustrate them by the new discoveries which advancing science is ever opening. ♦ Cic. Do Nat. Door., Lib. ii. c. x.xxv. t Lib. ii. c. xllv. % Plut. Do Plao. 1. 0. § optics. I Dctnonstration of Being and Attributes of Ood. 1* 10 ANALYSIS OF THE SECT. II. ANALYSIS OF THE ORDER IN NATURE LAWS OF NATURE. The most careless observer is led tc) notice, that there is a beautiful regularity running through nature as a whole, and through every individual part of it. This was discovered in very early ages of the world's history, by persons who had no very precise ideas as to its nature, or the means by which it was i3roduced. The Greeks, from the time of Pythagoras, embodied their impressions in the word by which they denoted the visible world, which they called Cosmos, to denote at once its order and its beauty, while the Latins styled the world Mundus, to express their sense of its surpassing loveliness. Ever since the time when the philosophic spirit was first awakened, reflecting minds have been speculating as to the sources of this order, and caught, at a very early age, glimpses of the truth. The philosophers of the Ionian School, which arose between 600 B.C. and 500 B.C., re- ferred it to the power and the varied transformations of certain elements, which they did their best to classify, as air, water, earth, and fire, representing the dry, the moist, the solid, the ethereal. In the speculations of this school, we have vague anticipations of modem chemistry, and in particular, of the doctrine of polar forces, in the balanced strife and friendships of Empedocles, and of that of de- finite proportions, in the " homoiomera" or equal parts of Anaxagoras. A rival school arose at a little later date, among the Greeks in Italy, and ascribed the order of nature, in a more profound spirit, to the power of Num- bers. We have no authentic or connected account of the system of the Pythagoreans, but it is evident, from the scattered notices wliich have been handed down to ns, that they represented numbers, the significance of ORDER IN NATURE. 11 which is SO clearly seen in music, as in some mysterious sense the principia of the universe. Aristotle tells us, that they considered existing tilings to be a copy of iium- hers,* and we have extracts preserved from the writings of some of the disciples of the school, describing numbers as being in the Divine Mind prior to the existence of things, as being used as a model (^nuQ&deiyfiu) in the formation of objects, and as that by which all things were brought together and linked in order. Among the disciples of the same school, and others who arose at a subsequent date, there was supposed to be a deep mean- ing in forms ; and the firoperties of certain figures, such as the triangle, the square, the parallelogram, the circle, the ellipse, were investigated with great care, giving us the science of geometry as the result. A very special in- terest gathered round certain numbers, such as seven and ten, and certain figures, such as the circle and triangle, which came in consequence to be regarded as perfect, or as sacred. From a still earher date, and as a manifestation of the same intellectual propensity, jjcculiar feelings be- came associated with certain recurring times and perio- dical seasons, such as the revolutions of the moon, the signs of the zodiac, and other cycles, which seemed to have a deep significancy in the economy of nature. De- mocritus, who lived 400 B.C., and the Epicureans, who flourished at a later date, sought for the origin of this order in the formation of all things out of atoms possessed of definite forms. The sublime ij:;enius of Plato ascrilted it to certain patterns after which all things were fash- ioned, which patterns he traced back to the eternal ideas of the Divine Mind. Aristotle, while correcting some of the extravagances of his great master, clung resolutely to the doctrine, that forms were as necessary as matter to * Mtittjoiv t(Vai ra ovra tCiv apiOixdi/. — Motapb. of Arls. 12 ANALYSIS OF THE the construction of tlie universe. The Platonists of the Alexandrian School literally revelled among numbers and forms, till they lost themselves among their intrica- cies and windings. The Platonizing Jew who wrote the Book of Wisdom, caught for a moment a very clear glimpse of the full truth, when he speaks of God "having arranged all things in measure, number, and weight."* Early science, like youth, is ardent, is eager, and not having as yet determined either its strength or its weak- ness, it would attempt every work, and works far beyond its capacity. Like the giants of the early world, it is ambitious, and would heap Ossa on Pelion, and mount to heaven, not by gradual and numerous steps, but by one old bold and presumptuous effort. In following this method of speculation, the sage — as he meditates on the banks of the Euphrates or Nile, along which an early civilisation had sprung up, or in the cities of Miletus, Elea, or Athens, in which the human spirit was sharpened by discussion and the love of enterprise — makes many a shrewd guess ; he anticipates not a few truths which later discovery confirms ; he awakens a spirit of inquiry which craves for a more accurate mode of procedure ; and if he does not settle, he at least starts questions which must sooner or later be settled. But his attempt, though characterized by enlargement of vision and power of vaticination, is, in respect of scien- tific strictness and certainty of result, a failure, and the favourite dogma of one school is ever disputed by tlie disciples of another school. It turns out that the work which one man or one school has attempted, needs, in order to its completion, the combined industry of many investigators continued through long successive ages. ORDER IN NATURE. 13 For just as when society makes progress there is a neces- sity for the division of manual labour, (as Adam Smith has shewn in the opening chapter of the Wealth of Na- tions,) so, in order to the advance of science, there is need of a division of intellectual labour. Most important of all, there arises, in the midst of the jealousies of rival schools and the noise of fruitless disputations, a demand for a surer, even though it should be a slower, method of investigation, — a method which wiU give results, be they many or be they few, which are not of the nature of in- genious speculations, to be set aside by other ingenious speculations, but ascertained truths, fixed for ever, and which all inquirers who come after may use, to help them to add to the accumulating stores of knowledge. It is late in the history of the world before such a plan comes to be systematically unfolded ; and it is to the glory of our country, a glory not exceeded even by that of the land which produced Plato and Aristotle, that the first exposition of it was by Lord Bacon. Since his days, scientific inquirers, according to their tastes, talents, and position, have betaken them each to his own field of in- vestigation, with tlie view of thoroughly exploring it ; and as the grand result, we have a settled body of truth, to which additions will be made from age to age. But as the deeply-underlying and prompting cause of all this intellectual activity, there is stiU the same crav- ing desire to find out the means by which unily and order are given to the great Cosmos. In tlicse days wc speak of all things being governed by laws ; we lay it down as a maxim, that the end of all science is the dis- cover}'- of law. The language may be more correct than that employed by the ancients, but it is far from being definite or incapable of misinter^jretation. For the ques- tion occurs, What is meant by laws in this application 14 ANALYSIS OF THE of the term ? Every one sees that, as thus used, it does not mean the same thing as when we speak of the laws of a country, of the moral law, or of the law of God. It is a term \\ith which we cannot dispense, but it is far from being unambiguous ; it is often used in an unlawful sense, and at times it is turned to the worst of puriDoses, as when it is supposed, that in referring an event to a law of nature, we have placed it beyond the dominion of God. When we speak of things being arranged in a law, or falling out according to a law, we signify, if we know what we mean, that all phenomena take place in a regular manner, that is, according to a rule.* It is the special office of each science to discover what the nature of the law is in its own department. This is the grand aim, so far as it has a grand aim, of all modern physical investigation, — to determine the rule to which the particular classes of objects under contemplation accommodate themselves. But in very proportion as the sciences have become subdivided and narrowed to particular facts, is there a desire waxing stronger, among minds of larger view, to have the light which they have scattered collected into a focus. As the special sciences advance, the old question, which has been from the be- ginning, will anew and anew be started, — What is the general meaning of the laws which reign throughout the visible world ? A correct and adequate answer to this wide question can be given only by a wide induction, and a combination of the results gained by a vast number of separate sciences, each conducted on its own principles. AVe live in the expectation of the approach of a time when science — the division of labour having fulfilled its ends — shall seek to combine its individual truths, and to * See a more minute analysis of the laws of nature In the Method of the Divine Govern- ment, Physical and Moral, B. ii. c. 1. ORDER IN NATURE. 15 realize the dream of its youth, and, as it were, carry iis to a mountain top, whence we may obtain not only a scattered view of the separate parts, but a connected view of the whole, and of the relative bearing and direction of every part. It appears to us that we are aj)j)roacliing the time when an answer may be given to the old ques- tion, and that this must be something like the following : — All things in this world are subordinated to law, and this law is just the order established in nature by Him who made nature, and is an order in respect of such qualities as number, time, colour, and form. We use the vague languages of such qualities, because science has not arrived at such a stage as to enable it to determine what these qualities are with anything Hke perfect cer- tainty and precision.* Every law of nature which can be said to be correctly ascertained is certainly of this description. We shall furnish abundant illustrations in the next Book of this treatise ; in this section we are merely to collect a few striking examples of the attention paid to each of the qualities named, and thus prepare the way for entering upon the separate sciences, when more systematic proof will be oflered. First, There is an Order in Nature in Respect OF Number. — Tliis important trutli, long believed in before it could plead any scientific evidence in its favour, was established and brought into prominence when Kepler unfolded the three laws which have formed, his- torically, the foundation of modci-n astronomy. It was ♦ A more scientific classification would probably give us active property Instead of colour, and Includinjj colour. There Is a curious combination of active properties con- stltutlni; Individual objects, and enabling us to classify tliom, wliich will be referred to in IJ. ill. c. 1 A. 2, but wbicb cannot be fully cleared up till we know more of the latent forces of nature. 16 OKDER IN RESPECT the confident expectation that there would be found some such principle of order which led that ingenious and persevering sage to make calculation upon calcula- tion, and devise one hypothesis after another, till, after nineteen unsuccessful attempts, his fine genius and his industry were rewarded by the discovery of the true laws of the planetary movements. These laws are, — that the planets move in orbits, which are elliptical in shape ; that if you draw a line from the planet to the sun, the areas described by that line in its motion round the sun are proportional to the times employed in the motion ; and that the squares of the periodic times are as the cubes of the distances. The first of these is a law of forms, the other two are laws of numbers. The dis- coveries of Kepler prepared the way for the still more important ones of Sir Isaac Newton. When the immor- tal work of this greatest of inductive philosophers was published, it was seen that the laws of Kepler were not original but derivative ; but the original law now unfolded belonged to the same class ; for the law of gravitation, the best established and the most univer- sally operative law yet determinetl, is a law of numbers. Turning to chemistry, we find that ever since it emerged as a science there has been a constantly renewed attempt to reduce its laws to a numerical expression. The only laws which can be reckoned as certainly determined in this science possess this character. The great law which lies at the basis of all the compositions and decompositions of substances, is that of definite propor- tions for equivalents, as expounded by Dalton. In the same science Gay Lussac discovered an arithmetical law, regulating the combination of gaseous substances, which unite in very simple proportions, according to volumes. Lest it should be thoudit that we are making a fanciful OF NUMBER. 17 reduction of the operations of nature, wc are liappy to be able to bring to our aid the name of Sir John Herschel. " Chemistry," says he, " is, in a most pre-eminent degree, a science of quantity, and to enumerate the discoveries which have risen from it from the mere determination of "weiglits and measures, would be nearly to give a synopsis of this branch of knowledge. "We need only mention the law of definite proportions which fixes the composition of every body in nature in determinate pro- portional weights of its ingredients. Indeed, it is a character of all the higher laws of nature to assume the form of a precise quantitative statement. Thus the law of gravitation, the most universal truth at which the human reason has yet arrived, expresses not merely the general fact of the mutual attraction of all matter, not merely the vague statement that its influence decreases as the distance increases, but the exact numerical rate at which that increase takes place, so that when the amount is known at any one distance it may be calcu- lated exactly for any other."* Similar language is used by Humboldt :— " The progress of modern physical science is especially characterized by the attainment and the rectification of the mean values of certain quantities by means of the processes of weighing and measuring. And it may be said that the only remaining and widely diffused hieroglyphic characters still in our writing — numbers, appear to us again as powers of the cosmos, although in a wider sense than that applied to them by the Italian school."f In looking at other de-partments of nature, we fii)(l similar examples of numerical order. Thus, ten is the tj'j^ical number of tlio fingers and toes of man, and, ♦ Ilcrschcl's Natural Philosophy, Art. IIG. t Cosmos, translated by Otti'i, vol. i. p. C4. 18 ORDER IN RESPECT indeed, of the digits of all vertebrate animals. It is also a curious, though perhaps not very significant circumstance, that in mammalia seven is the number of vertebrae in the neck,* and this whether it be long as in the giraflle, or short as in the elephant, whether it be flexible as in the camel, or firm as in the whale. In the vegetable kingdom we find that two is the prevailing number in the lowest division of plants, the acrogenous or flowerless ; thus, 2, 4, 8, 16, 32, 64, &c., are the num- ber of teeth in the mouth of the capsule in mosses. Three, or multiples of three, is the typical number of the next class of plants, the monocotyledonous or endo- genous ; and five, with its multiples, is the prevailing number in the highest class, the dicotyledonous or exo- genous plants. We shall shew, as we advance, that a curious series, 1, 2, 3, 5, 8, 13, 21, 34, &c., in which any two numbers added together give the succeeding one, regulates the arrangement of the leaf appendages of plants generally, and in particular of the leaves and the scales on the cones of firs and pines. In the inflores- cence of the plant we find that the outer organs, or sepals, always alternate with the petals which are next them, and that the whorl of organs further in, namely, the stamens, is generally either the same in number as the petals, or some multiple of them. When there is an exception to this rule there is reason to believe that there has been some abortion of the stamens ; and the traces of this abortion are not unfrequently visible in the rudiments of the organs undeveloped. Secondly, There is an Order in Nature in respect OF Time. — It is obvious that all such laws can be ex- pressed in proportional numbers, taking some fixed time * Apparent or real exceptions wiU be referred to afterwards. OF NUMBER AND TIME. 19 as a unit. But we are here introduced to a new funda- mental power, deserving of being put under a separate head. For the laws of which we are now to speak imply a peculiar arrangement in reference to time. We see the principle mogt strikingly exhibited in those move- ments of natural objects Avhich are periodical. No doubt, there is some disposition of physical forces necessary to produce this periodicity ; but this just shews all the more clearly that an arrangement has been made to produce the regularity. Tlie ancients were much struck with the order in respect of time of the celestial motions. The stars, the planets, and even the comets, were seen to perform their revolutions in certain fixed times. Some of them seem to depart from this rule only to exemplify it the more strikingly, for their irregularities, which are periodical, are as methodical as their more uniform movements. There have been regular epochs, to all appearance, in the changes on the earth's surface, and in the succession of plants and animals, as disclosed by geological science. The variations of magnetism on the earth's surface seem to be periodical, and attempts have been made of late to cormect this cycle with that which the spots of the sun are known to follow. There is a beautiful progression, as shewn by the science of embry- ology in the growth of the young animal in the womb, and the whole life of every living creature is for an allotted period. The plants of the earth liave their seasons for springing up, for coming to maturity, and bearing flowers and seeds ; and if this order is seriously interfered with, the plant will sooner or later be incapable of fulfilling its function. Thus the hyacinth may be prcnuiturely hastened into flower for one season, but the next year it will be found impossible to make it flower or pnjduce seed. In this way great natural events, and 20 ORDER IN RESPECT especially the life of animals and plants, the movements of the heavenly bodies, and the eras of geology, become to us the measurers of time, rearing up prominent land- marks to guide us as we would make excursions into the past or future, and dividing it for our benefit into days and months, and seasons, and years, and epochs. Thirdly, There is an Order in respect of Colour RUNNING through Nature.— Colour is not without its significance among the works of man. Every nation, every regiment has its distinctive colours upon its flags, which are its visible symbols and representatives. Colour appears as a peculiar mark on the stamps impressed by the post-office, and on many of our public conveyances. It is used as a signal by sea and by land, in our ships and on our railways ; it announces danger and proclaims safety. It has also, we are convinced, a meaning in nature. It has been far too generally supposed that colour obeys no laws in natural objects. It has been a very common impression, that it is spread indiscrimi- nately over the surface of earth and sky, animal and plant. We are sure that further research will shew that this is a mistake. It is true that colour has not so much value as form and structure in the classification of plants and animals. Still, we find that some tribes of algae are arranged by Harvey according to their colours, and that some fungi are classified by Berkeley according to the colours of their minute seeds. We are convinced that, amidst aU the apparent irregularities, there will be found to be some fixed principles in the distribution of colours in the animal and vegetable kingdoms, and, indeed, over the whole surface of nature. Seldom or never, for ex- ample, are the two primaiy colours, blue and red, found on the same organ, or in contact on the same plant. OF COLOUR AND FORM. 21 Liable to certain modifications, wliicli are limited, it is probable that there is a fixed distribution of colour for many families of animals and plants, and that this dis- tribution is fixed within still narrower limits for the species. It is certain, whether we are or are not able to seize it, and turn it to any scientific or practical purpose, that there are plan and system in the arrangement of colours throughout both the animal and vegetable worlds. Every dot in the flower comes in at the proper place, every tint and shade and hue is in accordance with all that is contiguous to.it. We shall shew at considerable length as we proceed, that the distribution of colours in the vegetable kingdom is in beautiful accordance with the now established laws of harmonious, and especially of complementar}^ colours. We shall likewise point out some very curious and interesting relations between the forms and colours of plants. The eye testifies, too, that there is an order in respect of colour in the decorations of insects, in the spots and stripes of wild beasts, and in the plumage of birds. "He who," says Field, "can regard nature with the intelligent eye of the colourist, has a boundless source of never-ceasing gratification arisinjr from harmonies and accordances whicli are lost to the untutored eye." Fourthly, There is an Order in Nature in respect OF Form. — We use the word form in a large sense, and as including not only figure, in the narrow sense of the term, but structure, which is the relation or connexion of fonns. Great attention is evidently paid to this quality in the construction of natural objects. It appears before us as a significant element in every department of nature. The planets, with their satellites, have a definite spher- oidal shape, and they move in orbits which have a cer- 22 ORDER IN RESPECT tain outline in space, namely, the elliptic. It is because strict regard is paid to this principle in the structure of the universe, that the science which treats of forms, that is, geometry, admits of an application to so many of the objects and arrangements of nature. And here it is worthy of being noted that the ancient geometers, from a general idea of the importance of forms, had carefully investigated the properties of those figures called the Conic Sections, (because capable of being produced by sections of the cone,) at a time when no very important application could be made of the propositions established by them. When Kepler discovered that the planets moved in elliptic orbits, the properties of the ellipse, un- folded so many centuries before by Apollonius and others, were ready to be a2)plied to the solution of a host of im- portant questions connected with the movements of the celestial bodies. It is instructive to notice that the clusters of stars revealed by telescopes of great power, shew regular forms, some of them being round, and a number of them having apparently a spiral tendency. ' In the mineral kingdom, we find forms playing an important part. In circumstances admitting of the ope- ration, most (if not all) minerals crystallize — that is, assume regular forms. These forms are mathematically exact in a variety of ways. Every perfect crystal is bounded by plane surfaces, its sides are parallel to each other, and the angles made by its sides are invariable. Each mineral assumes certain crystalline forms, and no others. These forms have now an important place allotted to them in the classification of minerals. They have been expressively designated the geometry of nature. But it is among organized objects that we find form assuming the highest significance. Every living object OF FORM. 23 composed though it be of a nuraber, commonly a vast number and complication of parts, takes, as a whole, a definite shape, and there is likewise a normal shape for each of its organs. The general or normal form which any particular tribe of plants or animals assumes, is called its type. Animals and vegetables, it is well known, are classified according to type ; and they can be so arranged, because types are really found in nature, and are not the mere creation of human reason or fancy. It is because attention is paid to type, and because it is so fixed and universal, that it is possible to arrange into groups the innumerable natural objects by which we arc surrounded. Without some such princi])les of unity to guide him, man would have felt himself lost, as in a forest, among the works of God, and this because of their very multiplicity and variety. In some cases the forms assumed by organic objects are mathematically regular. A series of beautiful rhomboidal figures, with definite angles, may be observed on tlie surface of the cones of pines and firs. It may be noticed, too, how the leaves and branches of the plant are placed round the axis in sets of spirals. The spiral structure is also very evident both in the turbinated and discoid shells of molluscs. Mr. Mosely has shewn that the size of the whorls, and the distance between contiguous whorls, in these shells, follow a geometrical progression ; and the spiral formed is the logarithmic, of which it is a property, that it has everywhere the same geometrical curvature, and is the only curve, except the circle, which possesses this pro- perty. Following this law, the animal winds its dwell- ing in a uniform direction through the space romid its axis. '' There is traced," says Mr. Mosely, " in the shell, the apjjlication of properties of a geometric curve to a mechanical purpose, by Ilim wlio metes the dimensions 24 OEDER IN RESPECT of space, and stretches out the forms of matter according to the rules of a perfect geometiy."--' We are reminded of the ancient Platonic maxim, that Deity proceeds by- geometry. The lower tribes of animals and plants often assume mathematically regular forms, such as the triangular, polygonal, cylindrical, spherical, and elliptical. It is seldom, however, that we meet with such rigid mathe- matical figures in the outline of the higher orders of organic beings. Those who have any sense of beauty will be grateful that trees are not triangular, that animals are not circular in their outline ; in short, that they have not taken any such painfully exact shape. Still, the forms of organic objects — such as the sweep of the veins of leaves and the outline of trees — though more flowing and waving, are evidently regular curves. There is truth, we suspect, in a favourite maxim of Oersted, "that inorganic beings constitute the elementary, and organic the higher geometry of nature." Besides the typical resemblances which enable us to classify plants and animals, and the beautiful curves which do so gratify the contemplative intellect, there are certain correspondences in the structure of organs which seem to us to be especially illustrative of a plan intelli- gently devised and systematically pursued. At an early date, these struck the attention of persons addicted to deep reflection, but it is only within these few years that they have been scientifically investigated and expounded. Aristotle noticed the corresj^ondence between the hands of man, the fore-hmbs of mammals, and the wings of birds, and between the hmbs of these animals and the fins of fishes, and spoke of it as an interesting species of * See Philosophical Transactions for 1838. t Soul of Nature, Uomei's translations, p. 343 OF FORM. 25 analogy, {>{cti'' uiaUyiav.) The profound mind of New- ton used to muse upon the symmetry of the animal frame : " Similiter posita omnia in omnibus fere anima- libus."' These correspondences, so far as vertebrate and certain portions of invertebrate animals are concerned, have now been examined w^ith great caTe, and we have a set of well-defined phrases to explain them. A homologue is defined as the same organ in different animals, under every variety of form and function. Thus the arms and feet of man, the fore and liind feet of quadrupeds, the wings and feet of birds, and the fins of fishes, are said to be all homologous. The corresponding or serially repeated parts in the same animal are called homotypes. Thus the fingers and toes of man, indeed the fore and hind limbs of ver- tebrate animals generally, are said to be homotypal. The phrase analogue has been reserved for another curious correspondence, found both in the animal and vegetable kingdoms. By an analogue is meant an organ in one animal having the same function as a different organ in a difiercnt animal. The dift'erence between homologue and analogue may be illustrated by the wing of a bird and that of a butterfly ; as the two totally differ in anatomical structure, they cannot be said to be homologous, but they are analogous in function, since they both serve for flight. "•■' These phrases, and the ideas on which they are founded, have taken their rise from the animal kingdom. But similar, though by no means identical, correspondences have been detected in the vegetable kingdom. The branch of botanical science which treats of the forms of plants is called morphology, and is now regarded as the * Seo Owen on IToinoloi^cs of Vertebrate Skeleton, p. 7 ; and Agassi/, onil Oould's Comiioratlve Pliyslology, j). 5, where the terms are aUlnltles and analogues. 2 26 ORDER IN RESPECT fundamental department of botany. We shall shew, as we proceed, that comparative anatomy and vegetable morphology supply illustrations, at once copious and striking, of an all-prevailing order in nature in respect of form or structure. As this order of facts comes before us, we shall see that science, in its latest advances, is fulfilling some of the an- ticipations of large-minded observers and deep thinkers, who, in earlier and unsophisticated times, looked upon nature with a fresh eye, and believed in the existence of a profound plan in it, when they were not able to give a scientific reason for their conviction. Systematic research is only coming up in these later years to the native beliefs and expectations which sages entertained from -the beginning. But there are these important diiferences between the early glimj)ses and the later dis- coveries : — that what was at first guess and vaticination, has become demonstration ; that what was at first a mixture of fact and speculation has become, by the inductive methods of weighing and measuring every phenomenon, unadulterated truth ; and we may add, that the realities disclosed by science far transcend in grandeur and true dignity the loftiest musings of the profoundest sages or the most brilliant speculators. It is to be regretted that the recent discoveries as to a harmony of structure running through the whole organic kingdoms have been turned by some to improper pur- poses. The famous German poet, Goethe, who did so much by his doctrine that all the appendages of the plant are leaves, or transformed leaves, (he should have said, formed after the same model as the leaf,) to found a scientific botany, has not defined his religious creed (we rather think he could not define it) ; but it is evident that he was by no means inclined to look upon nature as OF FORM. 27 the work of a personal God. The celebrated French com- parative anatomist, Geoffrey St. Hilaire, who laboured so effectually to prove that there is a unity of composi- tion in the animal structure, unfortunately (though no atheist) speaks in a contemptuous manner of final cause.* Lorenz Okeu, who pro})ounded the idea that the skull is a vertebrate column, (he should have said that the skull is formed after the same model as the back-bone,) was a pantheist, and sought, in a mystical rhapsodical manner, to find the beginnings of existence and of life without calling in a living or a personal God.f Yet the ideas which these men expounded, after being first denied and then modified and improved, have received the all but universal consent of scientific inquirers. Admitted, as they now are, among the establislied generalizations of science, and constituting, as they do, the most brilliant discoveries in natural history of the past age, they cannot be overlooked in a natural theology suited to the middle of the nineteenth century. If they are hostile — as we believe they are not — to the cause of religion, then let their exact force and bearing be measured ; and if they are favourable to theology, natural and revealed, — as we hope to be able to shew that they are, when properly interpreted, — then they require from their number and value, to have a very prominent place allotted to them. We have here a class of i)lienomena to wliich Paley has never once alluded in lii.s Natural Tlieology, and whicli are referred to only in an incidental manner, and with- out their meaning being apprehended, in one or two pas- sages of the Bridgewater Treatises.:}: The autliors of • See Vio, Travaux, ot Doctrine Scleiitinijuc (i"E. Geoffrey St. Ililalro, par .son Fil*, 0. Ix. t 8co Ph'. slo-Phllosophy, piisftim. t Dr. M'Cosh nttcniptiMl tliis In an article In the North lirltlsb Kevlow, for August 1851, of which this treatise may bo conslJored as an expansion. 28 ORDER IN RESPECT these works are not to be blamed for this omission, for in their day the facts had not been discovered, or, at least, admitted into acknowledged science. But now that they have taken their place, and that a very high place, among settled doctrines, it is time to examine their religious imjjort and tendency. They will be found not to be isolated or exceptional in their character, but to belong to a large and wide-spread class, possessing a deep theological signification. It is not pretended that these facts do of themselves prove that there is a living and personal God, clothed with every perfection. But they are fitted to deliver us from several painful and degrading notions, which may be suggested by the human heart in times of unbelief, or by persons who have been lost in a labyrinth built by themselves, and who are not unwilling that others should become as bewildered as they are. They prevent us from feeling that we, and all tilings else, are the mere sport of chance, ever changing its procedure, without reason and without notice, or, what is still more dreadful, that we may be crushed beneath the chariot wheels of a stem and relentless fate, moving on without design and without end. They shew us what certainly looks very like a method pursued dihgently and systematically — very like a plan designed for some grand end, so very like it that it behoves the sceptic to take upon himself the burden of demonstrating that it can be anything else. Taken along with their proper comjilement, the special adaptation of parts, they exhibit to us an enlarged wisdom, which prosecutes its plans methodically, com- bined with a minute care, which provides for every object and every part of that object. Conjoined with higher considerations, and, in particular, with certain internal principles, which have the sanction of the very OF FORM, 29 constitiitiou of our minds,'* they disclose to our faith a God wlio sees the end from the beginning, and who liath from the first instituted the plan to which all indi- vidual things and events have ever since been conformed. These objects so regularly constructed, and modes of procedure so systematic, fiU the mind, and prepare us, if they do no more, to wait for the disclosure of a loving being who may till the heart. For the intellect is not satisfied with contemplating, unless the heart be at the same time satisfied with loving. It is the grand mistake o^not a few gifted men, in these latter ages when physical nature is so much studied, to imagine that the order and loveliness of the universe, its forces, its mechanism, its laws, its weU-fitted proportions, will of themselves satisfy the soul. It will be found that all these, however fondly dwelt on, must, in the end, leave the same melancholy and disappointed feeling as the sight of a noble mansion doomed to remain for ever tcnantless — unless they lead on to love, and such love as can only be felt towards a living and loving Grod. * See article on Thelstlc Argument, in Appendix to Method of Divine Government, fourth edition. CHAPTER II. NATURE OF THE SPECIAL ADJUSTMENTS. SECT. I. NEED OF SPECIAL ADJUST3IENTS IN ORDER TO THE BENEFICENT OPERATION OF THE FORCES OF NATURE. . '' Order is Heaven's first law," and the second is like unto it, that everything serves an end. This is the sum of all science. These are the two mites, even all that she hath, which she throws into the treasury of the Lord ; and as she does so in faith. Eternal Wisdom looks on and commends the deed. As the separate physical sciences advance, they will necessitate the rise of com- bining sciences to collect their separate truths ; and this they may best be able to do under the two heads of order and special end. The science which treats of a certam important department of the first of these has already a suitable name allotted to it, and is called Homology. But we need a word to embrace the whole, and we pro- pose that this be Cosmology— that is, the Science of the Order in the Universe. We are aware that this term has been unfortunately devoted to an unattainable inquiry, which would penetrate into the origin of worlds ; but this makes us the more anxious to rescue so excellent a phrase from so degraded a use, and give it a profitable application. The other general science has already an admirable name appropriated to it in Teleology, or the Science of Special Ends. NEED OF SPECIAL ADJUSTMENTS. 31 Physical science, at its present advanced stage, seems to be at one with the Word of God, in representing all nature as in a state of constant change, but with prin- ciples of order instituted in order to secure its stability. " One CfENERATION PASSETH AWAY, AND ANOTHER GENE- ration cometh : but the earth abideth for ever. The sun also ariseth, and the sun goeth down, and HASTETH TO HIS PLACE WHERE HE AROSE. ThE WIND goeth toward the south, AND TURNETH ABOUT UNTO the north ; it whirleth about continually, and the wind returneth again according to his circuits. All the rivers run into the sea : yet the sea is not FULL ; UNTO the PLACE FROM 'WHENCE THE RIVERS COME, THITHER THEY RETURN AGAIN. AlL THINGS ARE FULL OF LABOUR ; MAN CANNOT UTTER IT : THE EYE IS NOT SA- TISFIED WITH SEEING, NOR THE EAR FILLED WITH HEAR- ING." There seems to be no such thing as absolute rest in nature. ^Ve are impressed with the ficldcness of the winds and the restlessness of the waves ; but the truth is, every other object is infected with the same love of change. There is probably no one body in precisely the same state in every respect for two successive instants. We think that we are stationary, but, in fact, we are being swept through space at a rate which it dizzies the ima- gination to contemplate. Every object in nature seems to have a work to do, and it lingers not, as it moves on, in tlic execution of its office. It exists in one state and in one place this instant, but it is changing meanwhile, and next instant it is found in another state or in another place. But there is an equilibrium established among these ever moving forces, and the i)rocesses of nature are made like the wind, to return according to their circuits. So iar as inductive science has been able to penetrate, it would appear that the active physical powers of the 32 NEED OF SPECIAL ADJUSTMENTS universe consist of a number of forces, or rather, we should say, properties, each with its own tendency or rule of action, and yet all intimately connected the one with the other, that is, correlated. I wave my hand in the air, and in doing so, I set mechanical power a-working. " The motion," says Mr. Grove, " which has apparently ceased, is taken up by the air, from tlie air by the walls of the room, &c., and so, by direct and reacting waves, con- tinually comminuted but never destroyed."* The produc- tion of mechanical power may be more distinctly seen if the hand is employed to move a machine. Mechanical power, it is well known, generates heat, and this heat, according to Mr. Joule, is in proportion to the mechanical power exercised. Heat may lead to chemical action, as when bodies are decomposed by a rise in the temperature. Chemical action is always accompanied by electricity, and electricity may produce light or galvanism or mag- netism. Gralvanism, again, may have an effect on nervous or muscular action, and muscular action may produce mechanical power. Thus we have the various known (or rather, perhaps we should say, unknown) forces pro- ducino: or exciting each other, accordino; to laws which have not yet been fuUy determined. Nay, if we turn in upon the organism itself we shall find traces of a similar circuit. For whence the muscular action that origi- nated the actions which we have mentioned ? Tracing it inwards, we find it conducting us to the nerves and the brain. But the brain is not an inexhaustible, nor is it a self-filled fountain of physical power ; on the contrary, if exercised in excess it becomes deranged in all its func- tions, or exhausted. In order to restoration of power, it needs, as every one knows, nightly rest, and also suste- nance ; and, on inquiring into the source of this suste- * Grove's Correlation of Physical Forces, 2d edit, p. IT. IN ORDER TO THE OPERATIONS OF NATURE. 33 nance, we find that it is derived from witliout, from animals and plants. Again, animals are fed by other animals and by i)lants, and plants by unorganized matter. The circuits are thus made to include all physical powers, oreranic and inorsranic. All these forces, distinct from each other, (so far as we know,) but intimately correlated, are made to balance each other, and to run in circles.* "We have introduced these generalized facts, which are indejiendent of all speculations as to the nature of the physical forces, for the purpose of shewing that these natural powers are all blind in themselves, and require an arrangement to be made — and this arrangement must jiroceed from intelligence — in order to their beneficial action. Heat, light, electric action, chemical composi- tion and dccompo.sition, organic affection — these are among the most powerful instruments of good in our world, but they become the most potent means of inflict- ing evil. In their bearings towards animate objects capable of j^leasure and pain, they may all be benignant, but they also spread misery and destruction. There is obvious need of a disposing mind to cause these various forces to act in harmony, and to issue in wise and bene- volent results. "Elements," says Faraday, "the most seemint ilelinitioii of irilnd reincsents it as essuntially a Self-niovini; power. We iiiiist ever 8et ourselves a;,'ainst the idea inainlaiiicd by some, that mental jiowcr U correlated to the pliyslcal and vital forces, as these arc correlated to eacli other. Wc never ean believe tliat the devotedness of the patriot, the se!f-sacrlllclnf{ spirit of the martyr, or the heroism which resists biibe and temptation, are eiijiable of beln;.; excited by heat, licht, and ma^'netlsin. In the same way as these can be excited by eaeh oilier. Uiit still It Is true that mind, we mean the human mind, can merely direct jihysieal force: It cannot create or orlu'innte it, it can merely turn it this way or that; but the power cxUts prior to any mental effort belnt; directed towarrls It, and when It is Set a-working, by the needful conditions being supijlled, it follows It own laws. 2* 34 NEED OF SPECIAL ADJUSTMENTS the varying phases of decomposition, decay, and death — then springing into new hfe, assuming new forms, resting in passive inactivity, or assuming the extreme of violence, according as either may be suited to accomplish the ap- pointed end."* It will be necessary at this place to state an important distinction which Dr. Chalmers had the merit of intro- ducing into natural theology in a formal manner. f He calls on us to notice how, the laws of matter being as they are, the results might have been different if a different set of collocations had been made of the bodies obeying these laws. Thus the law of gravitation still beino: as it is, the planetary bodies would have been moving in a very diflerent manner from what they do, had they been differently situated in reference to the sun and to one another. Had they not, for example, revolved in nearly one plane, they might in their revolutions have come into violent and destructive collision with each other. This is prevented by their being so disposed that their spheres can never intersect each other, that is, by their slrilful collocation. Dr. Chalmers thinks that the argument in favour of the existence of God should be founded on the collocations of matter rather than the laws of matter. The distinction is undoubtedly a sound one. In all discussions as to the material universe, we must set out with assuming the existence of body occupying space and exercising force, or rather active property. Now, it may be admitted that it is doubtful, to say the least of * Faraday's Lectures on Non-Metallic Elements. t Keference had no doubt been made to it before, as when Paley (Nat. Theol., c. iii.) fays, " I spe.ik not of the laws themselves, but such laws being fixed, the construction in both cases is adapted to them." But we owe tlie systematic announcement and expo- sition of it to the eminent Christian philosopher we have named. It is developed with his usual .vjiplitude of illustration in his Bridgewater Treatise and in his Natural Theology. A distinguished living writer who has done much towards introducing clearness into the logic of physical science, h.a3 adopted it, and made some new applications of it See Ullirs Logic, vol. i. p. 529, 2d edit. IN ORDER TO THE OPERATIONS OF NATURE. 35 it, whether we are entitled to argue that the. mere exten- sion of matter, that is, the circumstance that it occupies space, implies that it has been created. It might be further allowed, witliout any prejudice to the argument in behalf of the Divine existence, that the mere posses- sion of active properties does not prove, in a manner convincing to every one, that matter has been formed by an intelligent behig. The opponent, whether inclined to materialism or pantheism, might urge that in contem- plating the material world merely as exercising force and capable of motion, we are not imperatively called to sup- pose anything else than that power, be it a material thing, or be it a sjjiritual thing (as the pantheist maintains), resides in the bodily substance itself The argument of the pantheist, as against the materialist, would no doubt be overwhelming in such a case. The pantheist would be able to shew without difficulty that in the exercise of chemical, electric, luminiferous, calorific, and vital force, there is vastly more than mere extension or dead matter, and this he would call spiritual })owcr. But all this does not tend to prove that this spiritual power (so called) is of the nature of Intelligence, compassing an end by means employed for the purpose. When we have estab- lished on other grounds, the existence of a Divine or even of a s])iritual being, it might then be reasonably maintained that these physical powers, which have been shewn of late years to be more wonderful than men ever supposed them to be before, are not independent of the Divine Power, but arc rather one of the expressions of it. But when we are j)roving the being of a God, it might not be prudent to j)eril the whole argument on the prin- ciple that the exercise of active j)C)Wcr implies an intelli- gent and a personal God. It might be safer, to say the least of it, to argue the existence of Intelligence, not from 36 NEED OF SPECIAL ADJUSTMENTS matter considered simply as extended or as possessed of force, but from the material universe as it actually pre- sents itself, with its graceful forms, its lovely colours, its skilful adjustments, and harmonious laws. There are questions agitated in the present day in regard to the precise nature of the physical forces which strict induc- tive science is not yet prepared to settle, and there have been questions started as to the potency of matter in itself, which, in our opinion, the human intellect cannot very satisfactorily answer, and which may at least be answered in more than one way by different parties, with views and principles all equally favourable to religion. It seems more than probable that the very original properties of matter, whatever they be, have a rule, a law, so constituted as to suit them admirably to the purposes to be served by them in the universe. But this cannot be conclusively demonstrated till we have reached the ultimate properties of matter ; and we are not certain that we have found any one of the original forces of na- ture. The law of universal gravitation and the law of chemical affinity might seem to approach the nearest to simple and unresolvable powers ; but the illustrious dis- coverer of gravitation did not look upon it as an essential or ultimate property of matter, and Dalton represented chemical proportions as resulting from the size of the elementary atoms, and in the present day an eminent scientific man has proposed to resolve gravitation into a simpler property with a collocation suited to it ; while chemists generally are by no means inclined to affirm dogmatically that we know the original power from which the phenomena of the combination of bodies proceed. Were we at liberty to assume that these are ultimate properties, it might not be difficult to shew that there is a beautiful correspondence between the law of gravitation IN ORDER TO THE OPERATIONS OF NATURE. 37 and the mundane system through which it operates, and between the relations of the various chemical equivalents. But as we are not sure that we have gone down to the fundamental properties of matter, all that we can argue is, that if the adaptations do not consist in the adjustment of the original law to the objects, they must consist in the adjustment of the objects to that law. The truth seems to be, that they consist in the adjustment of the one to the other by Him who instituted both. But by no process can we get rid of these original adjustments. There is need, as Mr. J. S. Mill says, not only of a law of causation, but of a collocation of causes, and this collocation he shews " cannot be reduced to any law," that is, any natural law. With him, therefore, it is an ultimate fact of which he can make nothing. " We not only," he says,* " do not know of any reason why the sun's attraction and the tangential force co-exist in the exact proportion they do, but we can trace no co- incidence between it and the proportions in which any other elementar}^ powers in the universe are intermingled." But this we can clearly perceive, that if these proportions and coincidences had been different, there would have been confusion throughout the universe ; that if the cen- tripetal force had been proportionally greater, the earth and all the planets would have been drawn into the body of the sun ; and that if the centrifugal force had been much increased, the earth would have wandered into regions so far from the sun that all living beings must have perished. The beauty and fitness of these coinci- dences and proportions compel us to see, that though they do not proceed from natural law, they must proceed from an Intelligence jjlamiing all things, and the rela- tions of things, from the beginning. ♦ Mlirs Logic, vol. IL p. 44. 4 38 NEED OF SPECIAL ADJUSTMENTS Taking these principles along with us, we are entitled to say that mutual adjustments are necessary in order not only to individual effects of a beneficent character, but also to those general results of an orderly description, which are very commonly and very properly CiiUed laws of nature. We call the general facts observed by Kepler laws, but they are evidently the result of the relation of the planets to the sun, and of their centripetal to their centrifugal tendency. We talk of the law of the plant according to which it springs up, assumes certain forms, bears leaves and seed ; but every one sees that we have here a complex effect proceeding from a vast number of arrangements, in which the laws of vitality, whatever they be, with the laws of moisture, heat, light, and elec- tricity, are all made to act in unison. It seems to be a law of the ai:)pendages of the plant, of branches, leaves, and scales, that they are arranged in a spiral manner round the axis ; but no one looks on this as a simple law ; it is obviously the result of certain methodical disposi- tions. We suspect that most of what we call laws of nature, that most of the principles of order observable in nature, are of this compound or derivative character. They are the harmonious result of adjustments many and varied among a vast number of bodies and of forces, which, in our present state of knowledge, we must regard as different from each other, and which at least require adai)tations to be constituted in order to their operation in a beneficent manner. If these remarks be just, we are entitled to argue, that there has been adaptation not only in two or more bodies being so arranged as to jiroduce an isolated effect of a benign character, but also in their being so disposed as to produce general laws or general results, these being wide-spread and continuous, stretching through extensive IN ORDER TO THE OPERATIONS OF NATURE. 39 regions of space, and prolonged through many successive ages, such as tlie seasons, and the regular forms and periods of plants and animals. These — indeed all the j)rinciples of order in respect of numher, time, colour, and form — are entitled to he called laws. But they are not original, they are derivative laws, not simple hut composite, and the result of arrangements. We are thus enahled to connect the principle of order with the prin- ciple of special adaptation ; for it is required in order to the existence of general order, that there should be adap- tation upon adaptation, and these necessarily of a most ingenious and far-reaching character.* We shall have occasion to return, as we proceed, to this subject, as serv- ing to combine general law and special use in a higher imity. SECT. II. THE ADJUSTMENTS ARE DESIGNED, AND NOT CASUAL. NATURE OF CHANCE. The argument from design in behalf of the Divine existence, has sometimes been so stated as to make its main premiss a mere truism, and the whole argument a begging of the question. It sets out witli tlie maxim, that whatever exhibits marks of design must have pro- ceeded from a designing mind ; but by exhibiting marks of design, is meant proceeding from a designing mind, and thus the whole ratiocination is nothing but the pompous repetition of the same proposition. When put ♦ As the arranseiiK-nts needful are not only very numerous but very v.iried, It is pro- posed that tlie word adaptation or adjustment should be substituted for colluention— a phnuio which scoms to conflno the arrangements to those of place, whereas Ihcy may also include time, number, active property, &c. As these adjustments are necessary even to the production of those uniform results whicli we call laws of nature, the proper distinction is not between tlic laws of matter .iiid the collonillon of mutter, but be- tween the properties of matter aud Iho adjustments re(iulred in order to therson producing them. Every event has a cause, but every event is not causally connected with every other which may happen about the same time or place, or have some relation to it of property or number. This part of the truth is ex- pressed by Mr. J. S. Mill, — " Facts causally conjoined are separately the effects of causes, and therefore of laws, but of different causes, and causes not connected by any law. It is incorrect, then, to say, that any phenomenon is pro- duced by chance ; but we may say that two or more phe- nomena are conjoined by chance, meaning that they are in no way related through causation, that they are neither cause and efiect, nor effects of the same cause, nor effects of causes between which there subsists any law of co-ex- istence, nor even effects of the same original law of colloca- tion."* The meaning of the phrase, " law of collocation," and the use to which it may be turned in the theistic argument, as pointing to a designed adjustment in the original constitution of things, have already been noticed. So much, then, for casual as distinguished from causal connexion. But casual connexion may also be opposed to contrived connexion. It is needful to illustrate this, for it is a position of great importance in our argument. An agriculturist, let us suppose, is using the means ne- cessary to secure a crop from his ground. Every step which he takes must have a causal connexion with some- thing going before and something coming after ; to this * Mill's Logic, Book III. chap. xvii. NATURE OF CHANCE. 43 there can be no exceptions whatsoever. But among the nianv ao-encies he sets a-movino; there will be some which have no discoverable mutual relation, while there will be others which very visibly have such a relation, which, we would have it observed, may either be casual or designed. Thus it may be by accident that he began to plough the land on the same day as he did the previous year ; by chance that the two horses in a particular plough are of the same age ; that his harrows, constructed by different makers, are painted thq same colour ; that the workmen employed by him have the same Christian name ; and that he has precisely the same extent of land in crop as in the previous year. There may be many such relations and corresi^ondences which jiersons of a particular turn of mind find pleasure in noticing, and this because they are purely casual. But there are other connexions which are not of this fortuitous character. It is not by accident that he begins his work about the same season as he did the previous year ; that he has put two horses into his plough ; that the ploughing has been followed by sowing and harrowingr ; that he has workmen enira"^ed in tillin<2; his ground, and a certain portion of his whole ground under cultivation. There is here an evident distinction between two sets of events, and this distinction does not arise from the one class having causes, wliereas the others have not, nor from the two i)roceeding from alto- gether unconnected laws of collocation, but from the one being designed as a mean toward an end, and the other not being so designed, as having no reference to that end. This distinction between the concurrence of inde])endent means intended to produce an end, and mere coincidences whicli })romote no s])ecial end, is an all-important one in the argument from design or final cause. According to these views we cannot speak of an event 44 THE ADJUSTMENTS ARE DESIGNED. "being produced by chance. Such language has either no meaning, or a meaning opposed to the universally acknow- ledged principles of all science and all philosophy. In respect of causal connexion, chance has and can have no place ; it is absolutely excluded. But in respect of other connexions of co-existence or succession, of number and property, there is room for chance, and, as opposed to chance, of designed coincidences and correspondences, and a co-operation of associated means for the production of a given end. In respect of production there can be no such thing as chance, but in respect of disposition there may. There are mutual relations which are not designed, even as there are relations which are designed. We cannot speak of accidental occurrences, but we may speak of accidental concurrences. We are to shew that in the place where there is room for chance, there we have the most striking examples of design. It may be difficult at times to determine whether certain events or phenomena are conjoined by chance, or whether an arrangement has been made to produce the conjunction. It is no proof of an intended connexion that they have been conjoined once or twice, or a few times. Nor can any absolute rule be laid down as to fre- quency of co-existence, which shall decide every supposable case that may arise. But there are cases of designed con- currence so clear that they do not admit of a moment's hesitation. When we see independent agents all moving towards one end — when we see stone, lime, wood, glass, slate, and lead, all combined in a house — when we find various kinds of metals, and wheels, pulleys, cylinders, of various shapes and sizes, conjoined to jiroduce a machine, we at once say the connexion cannot be accidental, but is the result of arrangements made to secure a contem- l^lated end. NATURE OF CHANCE, 45 Let US suppose that, on entering a room, we discover on a table before us five or six balls formed into a ring- like fiffure, we do not allow ourselves for one instant to imajrine that the balls came hither of their oviTi accord, and without any one placing them there ; but it may be a question whether the mutual arrangements involved in the figure are accidental or designed. This question would at once be settled if avo saw other five balls on the same table formed into a similar figure. We would then acknowledge at once that there can be as little of accident in the mutual arrangement of the balls as in their Ijeing brought to this particular place. These distinctions and exjdanations enable us to bring out very distinctly the nature of the argument derived from adaptation of parts in favour of the existence of God. In physical nature we have the universal reign of causation, or every event connected with at least one other event as its cause, and yet another event as its con- sequence. In regard to this point there is no difference of opinion. But in perfect consistency with this doc- trine we may find a number of events occurring at the same time or place, or nearly at the same time or place, or having some sort of bearing towards each other of a purely accidental character. In this sense there is no doubt much of chance in this world, that is, many events have some sort of discoverable relation, which may yet have no intended connexion. The year in which a comet blazes in the heavens may be a year of famine or of fearful wars and intestine feuds, but this does not go to prove that the one was meant to forebode the other. We are quite willing to admit that all these phenomena can be traced uj) to God — we arc sure that God foreordaiiiL'd both the cranes which cover the brain 76 SPECIAL MODIFICATIONS and soft parts of the eye, &c., consist of inelastic fibre. By means of the yellow elastic fibre the claws of the feline tribe are kept retracted when not in use, and a strong band of the same material, stretching between the head, neck, and back, and acting as a, natural spring, enables many animals to keep their heads up without any active efTort on their part. Cartilage, or Gristle, consists mainly of cells, with in- tervening connecting substance, which may be homoge- neous, as in the purer forms of cartilage, properly so called, or the ceUs may have in the interstices white or yellow fibre besides. Elasticity, flexibility, as well as solidity, are properties possessed in an eminent degree by carti- lage. The cartilao-inous and fibro-cartilaginous modifica- tions of the cell type are produced in parts of the body where a solid material possessed of the properties above mentioned is required. The flexibility and strength of the soft part of the nose and of the external ear are ow- ing to the combination of cartilage and fibre. The ends of the bones forming the joints, have a covering of carti- lage, and being thus padded, they are less liable to injury by sudden shocks. The peculiar properties of the mate- rials in question perform an all-important function in the economy of the parts concerned in the formation of the voice. The strength and elasticity of the entire spinal column or back-bone depend chiefly on the inter- vening cartilages by which the entire series of pieces is connected. Muscular Tissue or Muscle, constituting the flesh, com- monly so called, presents, on careful examination, no very remote departure from the cell type ; in fact, the muscular tissue is essentially composed of modified cells, which, being first arranged in linear series, with greater OF THE CELL. 77 Fig. 7.* or less regularity, subsequently unite to constitute the elementary fibres. It is unnecessary in such a work as this, to enter into details regarding the two varieties of muscular tissue, called striped and smooth, and their respec- tive properties ; suffice it to say, that both perform most important functions in the animal economy. The active motions under the control of the will present the greatest possible variety in the amount of force exercised and the resulting effect. How diflerent the enormous muscular power exerted by the whale, when it throws itself entirely out of tlie water, from that put forth in the motions of the eyelids, or of the little muscles which are concerned in the modulation of the voice, and yet both are formed by the same tissue ! The giant steam-hammer which can weld a mass of iron, or simply crack the shell of a nut, is not more capable of control, and exercises no greatea: comparative range of force, than docs the muscular ap- paratus of the animal frame. In singular contrast with those masses of muscular matter subject to the control of tlie will, are those over which we have no control, fiucli as those of the heart, alimentary canal, &c. But wliercver voluntary or involuntary muscles occur, they are found precisely where each is most necessary in the aiiimiil ecunomy. Tim Bones. — But organs of a harder texture than any of those ah-eady descriljud, are required in the annual frame, eitlier to protect important parts, or to serve as levers for the active functions of certain muscles. With- out the bones the goodly frame of animals would be use- • Fio. 7. Smooth muscular flbro from the renal vtln In inivn ; shows coll typo. 78 SPECIAL MODIFICATIONS less ; a due combination of soft and of "hard parts is necessary ; active organs of motion must have relation to others which are passive ; levers must be provided to sustain and direct the force exercised by the muscular system. In a subsequent part of this work we shall have occa- sion to speak of types and modifications in the general arrangement of the animpJ skeleton ; it may be sufficient to state here that in minute structure the skeleton con- forms itself to the same type as the soft parts. But since hardness is requisite, there is superadded to the cellular element a very large proportion of earthy matter, consisting chiefly of phosphate of lime. Nervous Tissue is another modification of the cell type, for a very important function in the animal frame. The presence and peculiar functions of the nervous sys- tem specially distinguished the animal from the vegetable kingdom. The intercourse of animals with their fellows, and with the external world, depends on the presence of a system of nerves, which are necessary to sensation and to the exercise of every mental endowment. Whatever may be the form under which nervous matter appears in the animal body, whether fibres or ganglia, the modi- fication of the cell type can be traced in course of the development. Not only, however, do cells, or their modifications, act an important part in the protection of surfaces, the sup- port and strengthening of organs, and the performance of various active motions, they are also the chief instru- ments in other functions of the animal economy. With the exception of the simplest or very lowest tribes, there is in all animals a system of Vessels for the conveyance of fluid ; these owe their primary origin to cells arranged in linear series. In all animals havins: a true circulation, OF THE CELL. 79 simple isolated cells form an important part of the circu- lating fluid ; the Blood-Corpuscles — as they are com- monly called — to which that fluid owes its colour, are truly refeiTihle to the cell type. The food, after under- going certain changes in the stomach and alimentary canal, constitutes tlie fluid called chyle ; it is admitted that certain Epithelial cells select and absorb the mate- rials of the chyle, and, becoming turgid with them, subsequently transfer them to minute vessels — the lac- teals, which convey them to the blood-vessels. In the stomach and alimentary canal, certain cells are actively engaged in pouring out some peculiar and useful secre- tion. In the stomach such cells arc continually form- ing new broods, which pass out in great numbers, their contents yielding matters necessary in the process of digestion. There are organs whose function it is to separate matters for some special use, as the milk for the nour- ishment of the young, or to remove substances whose l»resence would be injurious if retained. It is unneces- sary here to enter into details regarding these various organs ; suffice it to say that their essentially important l)arts belong to the cell type. In short, we find that in the animal body sonic special modification of the cell is concerned in every important function. Cartilage, bone, muscle, nerve, serve different ends in the animal economy, but the cell is the essential element in each. The formation of an image in the eye is mainly effected by the ()])tical ])ropertics of parts having a cellular origin, and the impression is conveyed by another tissue, which, as we have already stated, may be referred to the Kamc general type. In a subsequent section we sliall have occasion to allude to tlie general structure as well as modifications 80 SPECIAL MODIFICATIONS OF THE CELL. of Teeth. Details respecting their mode of development would be out of place here ; it may be sufficient to state that cells perform an essential part in the formation of every tooth. Nails, Hoofs, Horn, are all essentially Epidermic pro- ducts, and necessarily partake of the nature of that part of the skin, that is, are modilications of the cell. Their importance in the animal economy is too obvious to re- quire discussion, serving as they do to protect delicate parts, and to act as means of defence and offence. Hairs and Feathers, notwithstanding their variety in color and texture, have a common origin in cells. The thick and warm fur of the hare, the smooth and silky coat of the mole, the spines of the hedgehog, the quills of the porcupine, and the coarse hairs — resembling split whalebone — of the elephant and ant-bear, are all mere modifications of the elemental cell, and each has a re- ference more or less obvious to the habits of the animal. The hairs of the mole are closely set, they stand out per- pendicularly ; in other words, have no particular shed, and thus present no obstacle to the rapid movements of this burrower when traversing its narrow and intricate subterranean tunnels. The spines of the hedgehog and the shar}3 quills of the porcupine are respectively admir- able means of protection to these otherwise defenceless animals. Feathers, constructed, as we have said, after the same cellular type as hairs, present similar modifica- tions in character, varying with the habits of particular birds. The soft plumage of owls enables them noise- lessly to steal on their agile prey. The thick-set feathers and down of divers and other aquatic birds, effectually repel the water and prevent soiling of surface, as well as loss of animal heat. CHAPTER II. THE FORMS OF PLANTS. SECT. I. ^TRACES OF ORDER IX THE ORGANS OF PLANTS. " When Jupiter," says Herder, "was summoning the creation, which he meditated in ideal form before him, he beckoned, and Flora appeared among the rest. Who can describe her charms, who can image forth her beauty.^ Whatever the earth showers from lier virgin-lap was mingled in her shape, her colour, her drapery." We are to attempt no description of her beauty, which can bo appreciated only by those who look upon her charms di- rectly, and not through any representation of them. But we are to attempt to give something like a scientific ac- count of that development and structure, of that disposi- tion of parts and distribution of colours, which mainly contribute to give to the plant its graceful proportions and its loveliness. Our present aim is to show that there arc system and design in the progress of the plant, from tlio time it sjirings from the seed to the time when it yields seed, and tliat there are determined types to wliich all its organs are made to conform themselves.'^ Botanists describe two modifications in the structure of the seeds of the liigher forms of plants. In a })ca or • W« aro to conHno our illustratlona lo flowering plants, pnrlly bocouso tlio ordor in thcBo cln-w'.^ ufplniiln Is inont vastly cxplulnud, but inolnly bcciiusc tlio morphology of the lower trlbfs of plant-i li;\t not been ho fully Invcatlgatod. 82 TRACES OF OEDER Fig. S.* bean, we observe that the principal bulk of the seed con- sists of two large bodies in close contact ; they are called seed-lobes, or seed-leaves, and, technically. Cotyledons. When two are present, the plant is a Dicotyledon. Be- tween these organs we ob- serve the rudiments of the future stem and leaves. In other plants, such as the oat, wheat, Indian corn, etc., there appears to be only one cotyledon, and such plants are called Monocotyledons. There is a difference between these two kinds of seeds as regards the process of germination ; but it will suffice for our purpose, to state that in both there is a general tendency in one part to fix itself in the soil, while the other tends to raise above it into the air ; the former is the root or descending axis, the latter the stem or ascending axis. Mere position in reference to the soil is not, however, an invariable test of the nature of a part whether stem or root ; fur there are not a few instances in which the true permanent stem is underground, as well as the proper root. But whatever be the position of these organs, we may see in the plant a continuous prin- cipal axis, one part of which constitutes the root, and the other the stem. Attached to the latter there are various appendages. * Fig. 8. Embryo of Poa, sbewint; the point where the young root arises, r; the young stem or plumule, g ; the stalk, t ; connected with the cotylcdoiis, c c, which are separated and laid open ; f, the depression in which the plumule lay. t Fia. 9. Vertical section of grain of oats, .shewing the embryo plant at the lower part, consisting of r , the parts whence the roots proceed ; g, the young stem ; c, the single cotyledon. The covering of the entire gniin, o ; covering of the seed proper, t; the nourishing mattei', or albumen, a. IN THE ORGANS OF PLANTS. 83 On the ascending axis of the plant, "we observe two kinds of appendages, leaves and huds. These last, how- ever, are mere repetitions of the plant ; each bud con- sisting of a short axis, and of lateral organs — the yoimg leaves. The Leaf, therefore, is the only essential typical appen- dage of the vegetable organism. It requires no minute description here ; the most inexperienced observer can recognize it it belongs to the class of " common things. The study of its many forms lies within the province of the botanist. While this typical appendage varies in outline, its general structure is simple enough. The outer surface Fig. 10.* Fig. ll.t Fio. 124 has a covering called cuticle or skin; the internal portion, parenchyma, as it is technically called, has ramifying ♦ Fio. 10. To shew curved venntlon of Kiulofren. t Fio. 11. To kIicw ilivcr(,'ent venatiun of Kiidoficn. % Fw. 12. To shew netted venation of Exogen— cherry leaf. 84 TRACES OF ORDER througli it the parts called veins.* These different parts, of which the leaf is made up, are all modifications of the typical cell, already described. Botanists have described a difference of the arrangement of the leaf-veins, between monocotyledons and dicotyledons. In the first of these two classes, there may be simple veins running more or less parallel to each other from end to end of the leaf {Fig. 10), or there may be only one principal vein (midrib) giving off lateral veins, all of which run parallel to each other {Fig. 11). In dicotyledons, on the other hand, there may be one or more principal veins giving off numerous branches and branchlets on each side, thus constituting a more or less complicated network {Fig. 12). Lilies, pahns, bananas, &c., present examples of parallel venation; the oak, beech, &c., have the netted form. But it may further be observed, that there is a relation between the structure of the stem and of the seed, and the venation. Dicotyledons have Fig. 13.* Fig. 14.t the stem conposed of concentric annual zones, as may be seen on a transverse section. Monocotyledons present no such appearance, the vascular parts do not form con- centric zones, but are broken up into bundles, giving a * Skeleton leaves, either prepared artificially or found among fallen leaves after long exposure to the weather, consist of these alone, skin and parenchyma having disap- peared. * Fig. 13. Transverse section, stem of oak, an F.vogen, or dicotyledon. t Fig. 14. Transverse section, stem of palm, an Endogen, or monocotyledon. IN THE ORGANS OF PLANTS. 85 dotted appearance to the stem when cut across. We may now proceed to examine certain appendages of the stem, in order to shew that although they are named as if dif- ferent in nature from stem and leaf, they are in reality modifications of one or other of these. Stipules are leaf-like organs, situated on either side of the point at which the leaf is attached to the stem, some- times adhering to the stalk of the leaf, at other times free. They have various forms, and differ also in size and texture, according to the plant in which we examine them. It may be observed, however, that they are not always present, and are not therefore necessary organs. They are evidently modifications of the leaf, and have the same general structure and functions. Pitchers. — These remarkable and beautiful appendages might afford models to the potter in the construction of vases for ornamental and useful purposes. Those of the Sarracenia of North America, usually called Indian-cups, and the still more remarkable and elegant organs of Nepenthes, or true pitcher-plant, are examples. They are all admitted by botanists to be merely modifications of the leaf type. FlajUodia, so called from their leaf-like appearance, are present in not a few plants. In some Australian acacias they are flattened leaf-stalks ; when young, they arc of narrow dimensions, and actually bear true leaves of small size ; when the true leaves droj) off, these modi- fied leaf-stalks increase in breadth. In some shrubby species of wood-sorrel, the transition from leaf-bearing to leafless flattened stalks can be clearly traced.* Hairs, scurfs or scales, glands, stings, and prickles, &c., * The phyllodia of Butcher'B-broom, of Xylopliylla, and of rhyllocliuliis, usually con- sidered to be flattened and leaf-like branches, may be taken as proof of the relation between branch and leaf. 86 TKACES OF ORDER are simple prolongations and modifications of the cells which form the external covering of the leaf or stem. In dandelion, and numerous other jjlants of the family Composita), as well as of some other natural orders, the divisions of the calyx become transformed into hairs or hair-like organs. Lenticular glands or lenticels, sup- posed to be connected with the formation of new or adventitious roots, and jDeculiar in their nature, are now known to be the homologues of cuticular appen- dages. They present, in different cases, a gradation to hairs, glands, &c. (See Comptes Rendus, August 1855.) Spines are abortive branches ending in sharp points. That this is their nature is evident from such cases as the following : first, they often produce buds and leaves, as in the hawthorn ; second, they have the same general structure as the stem and ordinary branches, and are therefore not appendages of the surface merely ; third, they occasionally become branched, as in Gle- ditschia. Tendrils are thread-like organs, which have the same properties as twining stems. They vary in their true nature. In Gloriosa superba, the midrib or principal vein of the leaf becomes lengthened, and assumes the appearance and functions of a tendril. In the Vanilla plant, the whole leaf sometimes undergoes a similar transformation. In the pea, vetch, &c., which have com- pound leaves, the end of the common footstalk forms the tendril. In Lathyrus aphaca, not merely the end, but the entire stalk of the compound leaf assumes a similar form. That such is the nature of the tendril in this plant is evident from the fact that occasionally a small leaf is developed upon it. In Smilax, the two tendrils at the base of the leaf are the homologues of the two sti- IN THE ORGANS .OF PLANTS. 87 pules, and the solitary tliread-Kke appendage or tendril at the point of attachment of the cucumber leaf, is also the representative of a stipide. The tendrils in passion- flower are the homologues of terminal, and in the vine, of lateral leaf-buds. The tasteful eye cannot fail to be delighted with the liveliness and freshness of summer tints, and the gorge- ousness of autumnal colouring, in the foliage of our forest trees. Variety of form ^nd diversity of size add to the assthetic feelings called forth by the umbrageous canopy of the vegetable world. Our pleasure and admiration are greatly enhanced when we proceed to examine more closely tlie disposition of the several j^arts. A casual glance, indeed, at a tree in full leaf, might leave upon the mind the impression that its parts were arranged according to no law, but this arises from the exuberance of the leafy covering hiding the wonderful method in the structure. A careful examination will soon reveal to us that vegetable arrangements are subject to mathema- tical laws, not less exact in themselves (though ad- mitting, for sfiecial ends, of wider deviations) than those which regulate the movements of the planets in their spheres. The arrangement of the typical appendages has been fully examined by Braun, Henslow, and others. The former has endeavoured to shew mathematically, not only that the spiral regulates the position of the appen- dages of the stem, but tliat each species is subject to fixed laws, by wliich tlie nature of the spires, and in many cases their number, is determined. The part of the stem or branch from which a leaf ori- ginates, is called a node, the intervening space an inter- node. Leaves are said to be alternate, when eacli node produces a single leaf, and when the successive leaves 88 TRACES. OF ORDER occupy alternately different sides of the stem. When there is such an arrangement, a line commencing at the first leaf, passing round the stem, and touching the point of attachment of each succeeding leaf, forms a sj^iral, the cycle ending with the leaf placed directly above the one from which we set out. When two leaves originate from a node, and are placed face to face, they are called /jVZ' opposite, and such position has been explained ^^^^ by some, on the supposition of two spirals pass- ing simultaneously up the stem. Three or more leaves springing from a node form a whorl; such po- sition may be owing to the ^^Jj::'r"f non-development of the inter- L'^ nodes of an entire cycle, each ^®' ^^■* spiral being thus reduced to a circle. In opposite and whorled leaves, we find not less evident traces of order as regards the individual leaves of suc- cessive nodes. In opposite leaves, for example, the pairs of leaves stand at right angles to each other; and in the whorled, the leaves of each often stand opposite to the spaces between those of the next. The beauty and simplicity of such an aiTangement as the spiral can be clearly seen and appreciated by exa- mining a branch of an Araucaria, or the cone of any fir.| Fio. 16.t * Fio. 15. A stem with alternato leaves jjrranged in aquinciincial manner. The sixth teaf is directly above the first, and commences the second cycle, expressed by fraction f . t Fio. 16. A stem with opposite leaves. The pairs aro placed at right angles alter- nately. t The spiral twisting of an entire organism, or of some of its parts, is worthy of notice here : for Instance, the stems of twinin?; plants, as honeysuckle, convolvulus, &c. The IN THE ORGANS OF PLANTS. 89 In the spiral, the number of turns made round the stem in completing the cycle is different, and we cannot do better than introduce here the following demonstra- tions and examples, as given in Professor Balfour's " Class-Book of Botany." Suppose that, commencing with a leaf No. 1, we reach leaf No. 8 directly above No, 1, after making three turns round the stem, the fraction indicating such an arrange- ment would be J. In another case we may reach No. 8 after one turn ; the fraction would then be 4. The frac- tions mark the angular divergence between any two leaves of the cycle, as represented in the divided circles Fig. it. Fig. 18. at the upper part of the stems. In Fig. 17, between 1 and 2, tlie angular divergence is obviously f of a circle, or ^ of 360° = 154^°. In Fig. 18, the divergence is 4 of the circle, or ^ of 360° == 51f. leaves of many plants while in tlie bud, of banana, for instance, and some ini) IN THE ORGANS OF PLANTS. 97 liable to be overlooked by a careless observer. In some species of rock-rose, and in Polygala, as well as in many other plants besides, some of the sejjals, or j^ieces of the calycine whorl, are lower or more external than the others, which are higher and Avithin the former. This prevalence of the spiral is especially obvious in the pistil or central part of the flower. The common strawberrj when ripe, illustrates this ; the numerous small pistih (or seeds, as they are commonly but improperly called) dotted over its surface, will be found, on clo.se examina- tion, to follow the sphal arrangement. The soft, juicy part of the strawberry is just an enlarged fruit-stalk, axis, or stem (receptacle of botanists), and the numerous minute pistils or seed-vessels which it supports, arc ar- ranged according to the same law which regulates the position of leaves, of which they are homotypes. Adolpho Brougniart long since showed, that what arc called floral whorls are not strictly such in many cases, but merely a series of organs closely approximated, and occu- pying different heights on the short axis. Tliis, as we have shown, is often sufficiently obvious as the natural condition of the parts, but it is at times more palpable in monstrous flowers. We have stated that ovules are of the same nature as buds. Since these latter, growing usually in the angle between stem and leaves, necessarily follow the law of the spiral in regard to position, the same ought to be true of ovules, and examples of this are easily found. Even when the ovules or young seeds are very numerous in a seed-vessel, there is no confusion, but the utmost regu- larity in their arrangement. Thus in the pod of a i)ea, where they form two rows, corresponding to the infolded edges of the typical leaf, those on one side alternate witli those on the otlier. In the seed-vessel of the Avall-flower, where they are more numerous, they follow the same law. 98 TKACES OF OEDER The regularity is not less obvious when we examine cases in which they are more abundant still, as, for example, in the seed-vessel of the common foxglove. It is worthy of notice, as an illustration of the same law, that the two seeds usually found at the base of each scale in the cone of a fir, are often not exactly on the same level, one being generally a little higher than the other. Not only are there relations of structure and position in the parts of the flowers, but we also observe relations in number. The typical flower in plants, having the dicotyledon- ous structure of seed, has its parts regulated by the num- bers four or five, or some multiples of them ; in flowers of monocotyledons, the number three, or some multi- ple of it, prevails. "••'■■ The fundamental structure in both may be modified in three ways ; 1st, by lateral adhesion of the pieces of the same series, or of organs of diiferent series ; 2d, by increase or diminution in the number of the parts ; Sd, by inequality of size and form, or union of the diiferent parts, or peculiarities in the development of the axis which supports them. Some botanical author- ities admit the existence of nine thousand genera, and about one hundred thousand species of the higher forms of plants.^ The characters of the former being founded * Linnaeus, in classifying plants according to the number of stamens, attached, prob- ably without being aware of tlae importance of the principle, a greater weight to num- bers than has been assigned to them by more modern observers. In Geraniums we may often observe five stems, five leaves divided into five parts, five flower-stalks, five sepals, five petals, and the stamens in multiples of five. In the natural family Umbel- liferae (carrot and hemlock are examples), the number five prevails not only in the flower, but it also seems to regulate the inflorescence, five or some multiple of it occur- ing very frequently in that part. The common elder-tree belonging to the Honey- suckle family, has five leaflets on a common stalk, the inflorescence or flower-.stem has five primary branches, each of these has in turn five secondary, and so on repeatedly ; five being also the typical number in the flower. In the true heaths, four is the typical number in the parts of the flower, but it (or its multiples) often appears also to regulate the number of leaves which appear together, as well as the number of flowers which are grouped together. t These numbers are doubtless fer above the mark, as regards plants actually dlscov- erod. IN THE ORGANS OF PLANTS. 99 on differences in the organs of reproduction, there are therefore numerous modifications of the typical flower. All parts of the plant furnish characters of species, and there are therefore many thousand modifications of the typical plant. Amid so much variety, it is pleasing to contemplate the common plan which regulates all ; and kno^nng that plan, we possess a key to explain those re- markable forms which are so common in the vegetable kingdom, whether the coronet-like flower of Napoleona imperiahs, the irregular flower of Aristolochia, or of the Balsams, or that peculiar slipper-shaped corolla from which Calceolaria derives its name. Tlie gaping flower of Mimulus, and the irregular mask-like flower of Lina- ria, are all referable to a common type. A knowledge of the typical flower in the Endogens enables us to ascer- tain the true nature of those modifications which render the grotesque flowers of the Orchids so remarkable ; in some it resembles an insect, in others a spider, and in a third case, a helmet with the visor up, indeed there is scarcely a common insect or reptile to which some of them have not been likened.* The flowers of the bee and spider orchis, the toad-like Megaclinium Bufo, and the Caleana nigrita of Swan River, whose flowers capture in- sects, and all the anomalous Cape species, can be inter- preted when we know the type. Having gone over the organs of the plant indivi- dually, we are now to inquire whether there may not be indications of a unity running through all classes of plants. Allusion has been made to two great classes of flower- ing plants called Monocotyledons and Dicotyledons, each characterized by peculiarities in the structure of seed, of stem, and of leaf (and also by a difference in the mode * Llndley'8 VcgcUble Kingdom, p. 170. 100 TRACES OF ORDER of germination of the seeds). Eacli also has, generally speaking, a certain number or its multiples regulating the number of parts in the flower. There seem, however, to be evidences that these two great classes, thus usually- distinguished, really possess much that is common. Ac- cordin*'- to Mohl, the structure of the stem of an Endo- gen and of an Exogen, during the first year of their growth, is altogether the same. Dutrochet indicates the Bryony as an example of such identity. As to the seed, Professor Lindley remarks, ■'•'• "It is apparent that dicoty- ledons are not absolutely characterized by having two cotyledons, nor monocotyledons by having only one. The real distinction between them consists in the mode of germination, and in the cotyledons of dicotyledons being opposite or in whorls, while in the monocotyledons tbey are sohtary or alternate." The difference in the arrangement of the veins of the leaves in these two classes present not a few exceptions ; thus, on the one hand, among monocotyledons we have examples of netted venation, as in Arum, Calla, Lilium giganteum, &c., and on the other, examples of parallel venation among dicotyledons, as in Nerium. There seem, therefore, to be transitional forms between the two great classes into which the largest proportion of the higher plants has been divided by botanists. There are indications, too, of a unity of structure run- ning through all the organs of the individual plant. We think it of importance to illustrate this at considerable length. It will not be reckoned by any scientific botanist, in the present day, as an excess of refinement to represent the developed organs of the plant as all formed after one or other of two different types or models, the Stem and the Leaf. * Introduction to Botany, vol. li, p, 26T, IN THE ORGANS OF PLANTS. 101 First, The more solid parts of the plant are composed of a number of stems, proceeding the one from the other in linear succession. Springing from the embryo, or seed, there is the axis mounting upward and becoming the aerial stem, and growing downward and becoming the root. From the former of these, or the ascending axis, there go off lateral stems, which we may call branches, and from these, other stems, which we may call branch- lets. There proceed, in like manner, from the descending axis, or top root, lateral branches which also ramify through the soil. There are important differences be- tween the aerial and the subterranean stems to fit them for their different functions. Boots, for example, have no pith, no scales or leaves, and, in ordinary circum- stances, no leaf-buds like the upward axis. Still the two are alike in the general character ; the branched plant is found to have a branched root. The tendencies of the underground ramification have not, so far as we know, been carefully determined ; l)ut above ground, it is very evident that the stem, branch, and branchlet obey the same laws. ''If a thousand branches from the same tree," says Lindley, " are compared together, they will be found to be formed upon the same uniform plan, and to accord in every essential particular. Each branch is also, under favorable circumstances, capable of itself becoming a separate individual, as is found by cuttings, buddings, graftings, and other horticultural i)rocesses. This being the case, it follows that what is proved of one branch is true of all the others." AVe have seen a pear- tree laid prostrate on the ground by storms, but, with its roots still fixed in the soil, sending out a branch from its side, which mounted upward, and took a foim precisely like that of the parent tree. The other typical or model form is the leaf. We have 102 TRACES OF ORDER sliewii that all the appendages of the plant are constructed on this type. " Linnasus had a presentiment of some- thing of this kind, and, in his Prolepsis Plantarum, carried it out in such a way that, starting from the con- sideration of a perennial plant v/ith regular periodicity of vegetation, as in our forest trees, he explained the col- lective floral plants, from the bracts onward, as the collec- tive foliar produce of a five-year-old shoot, which, by anticipation and modification, was developed in one year. This view is, in the first instance, taken from the most limited point possible, from the examination of a plant of our climate ; and secondly, imagined and carried out with great want of clearness." '■•• The true doctrine was first propounded by C. F. Wolff (Theoria aenerationis, 1764), but his treatise lay buried in neglect till the doc- trine became established by the influence of others. It was first presented to the world by the great German poet, Goethe, who, though not learned in the artificial botany at that time taught in the schools, had a fine eye for the objective world. We are not willing, indeed, to admit that the form in which Goethe expounded the doctrine is in every respect correct. It is wrong to repre- sent floral organs as metamorphosed leaves, for they never have been leaves in fact ; the accurate statement is, that these organs and leaves are formed after the same general plan. Nor are we to represent nature as striving after a model form, which she fails to reach, in the va- rious modifications of organs ; for the modifications are as much an end and intended, as the parts which may be pointed to as patterns. Still, Goethe may be regarded as having seized the great law of vegetable morphology. His Versuch die Metamorphose der Pflanzen zu erklaren, was published in 1790, and has furnished the foundation * Schleiden's Principles of Scientiflc Botany, translated by Lankester. IN THE OEGANS OF PLANTS. 103 to scientific botany. But as Goethe had no name among the initiated, little attention was paid by botanists gene- rally to his spccnlations till long after, when they were mentioned by Jus- sieu, and brought into general" notice by De Can- dolle, in his " Organogra- phie," published in 1827. The doctrine, somewhat modified, is now acknow- ledged by the great doctors, and has been sanctioned by the great councils of science. According to this idea, a plant is composed of two essentially distinct parts, the stem and leaf. The leaf is attached to the ascending stem, and be- sides its common form, it takes, while obeying the same fundamental laws, certain other forms, as scales, bracts, sepals, pe- tals, stamens, and pistils. Schleiden, who has deve- loped this view, gives, in his " Plant, a Biography," a picture of a typical plant con- structed on this principle. This makes a plant a dual. ♦ Fir.. 23. The typical plant— 1 to 7. Axis. I. to VI. Appendages.— I. Cotyledon; II. Leaves; IIL Calyx; IV. Corolla; V. Sta- men ; VI. Pistil. II. Typical appendaRes. I. III. IV. V VI. Modified appendnfcca i b, Buds composed of nhortened axes, with rudimentary ui)pendages. Fio. 23.* 104 TRACES OF ORDER But it appears to us possible to reduce a plant by a more enlarged conception of its nature to a unity, that is, to shew that there is a unity of plan running through- out the whole.* Looking first at the ramification of the stems, we may observe a central stem, or central stems, sending out other stems at definite angles, and of a normal length, and altogether in so regular a manner that the whole plant is made to take a predetermined form. Looking next at the venation of the leaf we perceive (see Figs. 12, 24, 25, 26) that it too has a ramified character, that it has in the centre a main rib, or ribs, from which pro- ceed other ribs or veins in so definite a manner that the whole skeleton assumes a regular shape. Now, we main- tain that a number of correspondences can be detected between the ramification of the stems and the ramifica- tion of the leaf- veins. In prosecuting this inquiry, let us first inspect, in a general way, the leaf of a tree, with its central vein, or veins, and its side veins. (See Figs. 12, 24, 25, 26.) On the most cursory inspection the impression will be left on the mind that the central vein, or midrib, as it is called, corresponds to the central stem or axis of the tree, and its side veins to the branches. Having seized the figure of the leaf-venation in the first instance, let us now look at the skeleton of the tree, say a tree stripped of its leaves in winter, and we may notice how like it is in its disc and the arrangement of its parts to the skele- ton and outline of a leaf. We shall be particularly struck with this if we view the tree in the dim twilight, * Dr. M'Cosh has here to express his obligations to Professor Balfour of Edinburgh who, without prematurely committing liiinself to these views, has kindly helped to give them publicity and bring them under discussion. See Transactions of Botanical Society of Edinburgh, July 18S1, and Balfour's Class-Book of Botany, 2d edit. p. 113; see also Sectional Reports, for 1852 and 1854, of British Association for Tromotiou of Science. IN THE ORGANS OF PLANTS. 105 or " pale moonlight/' between us and a clear sky, as we may conceive Wordsworth to have viewed it. " Often have I stood, Foot-bound, uplooking at this lovely tree, Beneath a frosty moon." We are quite aware that, in the tree, the branches go off all round the axis, and give to the whole figure a sphe- rical form, whereas in the leaf the fibrous veins all lie in one plane. But then we have a transition from the one to the other, and a point of connexion in the branch, the branchlets of which- — as, for example, visibly in the beech — often lie in one plane, and, if filled up, would make the figure bear a resemblance to the leaf. The principal difference between the tree and leaf may pos- sibly be found to consist in this, that for special ends the cellular tissue which, in the tree and its branches, is col- lected into the pith and bark, (which are connected by the medullary rays,) is in the leaf spread out so as to fill up the interstices in the fibrous matter which forms the veins. The general impression produced by the first thoughtful survey of a morphological correspondence between stem ramification and leaf ramification will be confirmed by a more searching and scientific investiga- tion. In maintaining tliis, we always assume that in the cases subjected to examination both stem and leaf are fully and fairly developed. But here it will be necessary to have it settled, at the outset, that every species of plant tends, if allowed to grow freely and in favorable circumstances, to take a particular f)rm, and that the same is also true of the leaf This statement will be allowed, after a moment's recollection and thought, as to the leaf. Tlie cherry leaf {F'kj. 12) obviously assumes one sliape, the beech leaf {FUj. 24) anotlier shape, the lime leaf {F'kj. 25) a 6* 106 TRACES OF OKDER third shcape, and the poiDlar leaf {Fig. 26) yet a different shape. Every one who has used his eyes will remember that the oak leaf has its peculiar figure, and the thorn leaf its own conformation, and the birch leaf its specific outline, by which we at once recognise them and distin- guish them the one from the other. A very little patient observation of trees growing freely — of lawn-trees, for example — may satisfy any one, that what is true of the leaf is also true of the tree. Every species of tree, ac- cording to naturalists, has its own habit ; and this gives to it a peculiar physiognomy by which the practised eye will at once recognise it. We have often found it in- teresting, (when we had nothing else to interest us,) in passing along a road, to detect, by their configuration, the various species of trees which met the eye, and this when they were bared in winter, and there was no foliage to aid us. Towards this normal shape of its species every individual tree tends. No doubt it is greatly interfered with, and much thwarted in its efforts by prevailing winds which bend it, or violent storms which break it, by too much cold at one side, or too much sunshine at another side, by a niggard soil denying nourishment, or officious neighbours jostling it, by cattle browsing on it, or men cutting it ; still we can see the native tendency in the most unfavourable circumstances, while, in more favoured positions, we see the tree grow- ing up to its beau-ideal. And here it may be laid down as a general rule, that every plant takes the fairest shape when allowed to assume its natural form. True, there are trees which have been rendered picturesque by being torn or twisted by the storm, or venerable by the marks of age ; but being unaided by associated feelings produced by such causes, the plant is always injured when attempts are IN THE ORGANS OF PLANTS. 107 made by man to give it an artificial shape. Every tree should be allowed fairly to develop itself, protected only from rude Avinds, and interfering neighbours, and graz- ings of cattle, and prunings of man, who so often ]nars in attempting to mend. All ornamental pruning should aim, not at improving, but aiding nature — nay, not so much at aiding it, as cutting off unnatural additions and removing artificial imperfections. Thus left to their innate tendencies, all plants will grow into a form more or less beautiful. A tree growing freely and fairly in a lawn, where it has soil to feed it, and space to develop itself, and air to breathe in, and sun to warm it, and fences to shelter it, stands before us a most interesting object of contemplation. The parallel branches, and their spiral arrangement round the axis, their sweep of curve, and the methodical way in which they first lengthen and then shorten as they ascend the trunk, and the graceful rotundity and elegant outline of the whole between us and the sky, all combine to fix the eye, and unconsciously excite and engage the musing intellect. And there is another beauty ])roduced by a number of differently-formed trees standing on the same lawn, and each shewing its separate mould and featiu-es. For as one star differeth from another in glory, and as one saint in heaven differctli from another in glory, so one tree differeth from another in glory. There is one glory of the oak, which looks as ii' it had faced a hundred storms, and having stood them all, were ready to face as many more ; another glory of the sycamore, that " spreads in gentle pomp it honeyed shade I" another glory of the bircli, so graceful in the midst of its maiden tresses ; an- other glory of the elm, throwing out its wide arms as if rejoicing in its strength ; and another glory of the lime, with its sheltering shade inviting us to enter and to linger. 108 TRACES OF ORDER Each has its own glory, of which it would be shorn were it to make an ambitious attempt to usurp the glory of its neighbour. It being allowed that there is a pattern form for the whole plant and for its leaf, we are now to trace certain interesting correspondences which we have noticed be- tween the two.* 1. In plants with looody structure, there seems to he a correspondence hetween the tree and leaf in this 7'espect, that a leaf ivithout a leaf-stalk implies a trunk naturally branched from the ground, and a leaf luith a leafstalk implies that the species of tree on lohich it groios has naturally a hare stalk. — In order to the settlement of this point, it is necessary to have it admitted that there are trees which are naturally feathered from the base, whereas there are others wliich have less or more of an unbranched trunk. Belonging to the former class we may name the greater number of our ornamental lawn shrubs, as the box, the holly, the laurels, bay and Portugal, the ar- butus, the laurustinus, the privet, the snowbcrry. All of these cover the lawn from near the base, and it may be observed of the leaves of all of them, that they have no petiole, or a very short petiole. To this same class belong many of the common forest trees, such * Oiir observations have been extensive and varied, but (hey are limited when com- pared witli the whole vegetable kingdom, and so we are prepared to expect that curious modifications and anomalies will cast up, which, while not setting aside these general views, will open new views, and enable science, in the end, to rise to a more thorough conception of the plant. + Fk;. 24. Beech leaf, as an example of leaf with little or no leaf-stalk; shewing nearly parallel veins; angle of venation, 45° to 50°; the midrib zigzag. Fio. 24t IX THE ORGANS OF PLANTS. 109 as the oak, the chn, the beech. The leaves of these trees have little or no leaf-stalk, and we are able, from a ratlicr extensive observation, to affirm that these trees incline to send out branches from the base. At times, indeed, this tendency is interfered with. In fields, the lower branches are frequently eaten by cattle, and in thick woods they often fail from want of air. The lower branches of the young oak are studiously cut off by woodmen, in order to get a tall, unbranched trunk for timber. The beech is not unfrequently cut over before being planted out in lawns, and a whorl of brandies is made, in consequence, to spring out some few feet above the ground. In England, the favorite elm is often pruned near the base, in order to lessen the shade upon the field or highway. But when allowed to grow unmo- lested, and in favourable circumstances, these trees are all bushy from the base. The very circumstance that the oak requires pruning in order to its having a bare trunk, proves that its own tendency is otherwise. The beech shews that it is naturally branched from the roots, by the closeness of the hedges which it forms. The pruned elm is ever displaying its native disposition, by the little branches that crop out from its trunk in spite of all the cutting to which it is subjected. Other trees, again, have less or more of a bare trunk, and the leaves of these have less or more of a leaf-stalk. To this belong the cherry, {Fig. 12,) the lime, {F'iject, knows that thorns need con- 110 TEACES OF OKDER stant cutting to keep them from becoming bare near the root, and their native habits are seen when they are planted out in lawns, where they have invariably (as the beautiful thorns in Phoenix Park, Dublin, can testify) an unbranched trunk. 2. TJiere is a correspondence between the disjjosition and distribution of the branches, and the disposition and distribution of the leaf veins. — Some trees, such as the beecli, the poplar, the birch, the oak, have one main axis, from which there proceed comparatively small side branches, pretty equably along its length ; and it will be found in such cases that the leaf (see Figs. 12, 25) has one central vein, with pretty equally disposed veins on either side. Other trees again, incline rather to send off, at a particular height, for each species, a number of branches at once. This is the case with the lime, the common sycamore, and the horse- chestnut. The lime has a few feet of unbranched trunk, and at the place at which it begins to branch there will commonly be noticed a cluster of branches, which, as they droop down give to that tree its attractive shade, and, in correspond- ence with this, we may observe that the leaf has a petiole, * Lime leaf, as example of a leaf with a leaf-stalk, shewing a clustering or whorling of veins at the point at which the veins begin to come otf, and a nearly paiallel venation. The angles made by the lateral veins from tlie midrib are 42°, those made by the veins procce.Iing from these main lateral veins are 50°. The angle a a corresponds to the angle of the peduncle upon the branch. Fig. 25.* IN THE ORGANS OF PLANTS. Ill at the top of which there is a chistering of lateral veins. The trunk of the sycamore, about eight or ten feet above the surface of the ground, commonly divides itself into four or five large branches, and, in precise analogy, we find a pretty long leal-stalk dividing into five midribs. Tlie horse-chestnut often sends off at the top of its bare trunk (as may be seen in hundreds of trees in Bushy Park) a still greater number of branches, and in corre- spondence with this its leaf is commonly divided into seven leaflets. This correspondence between branching and venation is very strikingly displayed in those' j)lants which have triplet leaves, such as broom and laburnum ; a careful observation of a number of such will satisfy any one that the axis, in the one a few inches, and in the other a few feet, above the ground, inclines to divide into three main branches. In some j)lants there is a whorling (approximately in the sense explained, p. 96) of leaves at the point at which they issue from the stem ; this may be seen in rliododendrons, the common barber- ries, and azelias. In these plants the branches also go off in whorls, as any one may satisfy himself by the most cursory inspection. This morphological correspondence may be seen in her- baceous plants as well as in plants with woody structure. We have the triplet leaf and triplet stalk in marsh-trefoil, in wood-sorrel, and clover, and the whorled stalks, with a clustering of leaves or midribs, in lady's-mantle, gera- nium, mallow, and lupin. In common lady's-mantle there are several midribs, and, in the mountain species, a whorling of leaves, and in both a tendency to wh(jrl in the stalks. So far as we have been able to generalize a very exten- sive series of facts before us, we are inclined to lay down the provisional law, that the whole leafage coming <»ut at 112 TRACES OF ORDER one place on the stem corresponds to the whole plant, and that the venation of each single leaf corresponds to the ramification of a branch. We state the general axiom in this form, because in many plants more leaves than one issue from one point, and in such cases it seems t(~» be not the single leaf but the whole leafage which is the type of the tree. 3. There is a correspondence between the angle at ivhich the branch goes off and that at ivhich the lateral veins go off. — And here, again, it will be needful to have it admitted that there is a normal angle both for the lateral leaf veins and the lateral branches. So far as the lateral veins are concerned, it will be acknowledged, by every one who has ever looked with care at the form of a leaf, that there is a normal angle for every species of plant. An inspection of any leaf picked up at random will shew that the lateral veins run nearly parallel to each other (see cherry leaf. Fig. 12, beech leaf. Fig. 24, lime leaf, Fig. 25), and that in certain plants, as at the base of the poplar leaf, for example (see Fig. 26), the veins go oif at a much more obtuse angle than in certain other plants, as, for instance, the lime (see Fig. 25). The leaves of the elm and hazel have some resemblance to each other, but may at once be distinguished by their angle of venation, which in the former is 55°, and in the latter 40''. It will not be so readily allowed that there is a normal angle at Avhich tlie branch goes off in every species of tree. We have heard it maintained that a branch sets off from the axis as best it can, taking any empty space available to it, and in search of air to breathe in and sun to warm it. But a very little careful observation, with this special object in view, may satisfy- any candid mind that this is not the case, and that the branches tend to go out very much parallel to each other, IN THE ORGANS OF PLANTS. 113 and at a normal angle, for every species. Any one may see at a glance that tlie elm and oak branch goes off at a wider angle than that of the birch or beech. No doubt many external circumstances tend to interfere v.dtli this internal tendency. A branch will often be bent down by its own weight, or turned u})ward by another branch, or by want of room and an, or spoiled by cattle or chil- dren, or men, still the tendency will manifest itself, even when thwarted ; and in every open lawn, duly sheltered, there will be trees whose skeleton beautifully displays the native direction of the branches, which will be seen, like the leaf veins, to run very much parallel to each other, and within a few deorrees — now on the one side and now on the other side — of an average or normal angle, which may be ascertained by a number of measurements. When it is acknowledged that there is a normal angle both for vein and branch, what we may call the angle of venation and tlie angle of ramification, the question is started, and admits of being answered. Is there a correspondence between the two ? We may satisfy ourselves that there is, in a general way, by a bare inspection, or by taking a leaf, abstracting its soft matter, and then looking through the skeleton venation upon the ramification of the branches, and comparing the two. Or the point may be settled more scientifically by using a goniometer, consisting of a graduated semi- circle with a movable index, and measuring the angle both of vein and brancli. The angle of the vein is easily ascertained, and the angle of the branch may also be obtained approximately by taking a series of measure- ments and striking the average. By such means it can be proven that there is a correspondence between the angle of venation and ramification of each species of plants. In most plants with v,roody structure the angle 114 TKACES OF OEDER of both vein and branch ranges between 45° and 60°. In the greater number of herbaceous plants* the angle varies from 25° to 40°. But both in, trees and herba- ceous plants there are angles so acute as 10° or 15°, and so obtuse as 70° or 75°. So far as we have observed there are no normal angles more obtuse than the number last named, though branches are often bent down by their own weight, so as to stand perpendicular to the axis, or are even inclined at an acute angle to the part of the trunk below the point from which the branch springs. For every species of plant which we have examined there is a definite normal angle or angles. We say angles, for the angles may diifer at difierent parts of the venation and ramification of the same plant. Thus, in some plants the angle of ve- nation is widest at the base, and gradually narrows as we ascend. Whenever this is the case in the leaf there is a similar narrowing in the angle of the ramification of the branches. It is seen in a marked manner in the pop- lar and the beech, and helps to give to the leaves and coma ^'<'- 26+ of these trees that rounded pyramidal form by which they are distinguished. More frequently there is a difference between the angle at * Dr. M'Cosh has hore to cxpross his obligation to a most excellent but extremely modest man, Mr. Mitchell, formerly schooliiiastor at Edzcll, now ia the City Mission. Kdinbnrgh, for help in applying his theory to herbaceous plants. I Fig. 26. Poplar leaf, as an example of leaf with leaf-stalk. The primary angle of venation begins at 70", and lessens as we ascend llie midrib. IN THE ORGANS OF PLANTS, 115 which the main lateral veins and main lateral branches go off from the midrib or axis, and that at which the lesser veins and branches go off either from the midrib or axis, or from the main lateral veins and branches. We may call the former of these, that is, the angle made by main veins and branches, the primary angle, and that made by lesser branches and veins, the secondary angle. In looking at the lime leaf, {Fig. 2.5,) we may notice that the main veins (primary) go off at a much more acute angle than certain smaller veins (secondary). Using this nomenclature, we have found that the primary angle of the venation of the leaf is the same with the primary angle of the ramification of the stem, and that the secondary angle of venation is the same as the secon- dary angle of ramification. In measuring angles, then, it will be necessary to dis- tinguish between the primary and secondary angles of ramification and venation. In applying this distinction to herbaceous plants, we found that the angle at which the peduncle, that is, the flower-stalk, goes off, corresponds not to the primary, but secondary, angle of venation. In following out this system, however, we often experience a difficulty in ascertaining whether we arc measuring the angle of a true branch, or peduncle, as botanists do not seem to have laid down any rules to enable us to distin- guish between these organs. It appears, then, that on inspecting the ramification and venation of any given plant, we may observe a nor- mal primary angle which is the same both for main lateral vein and main lateral branch, and also a secondary normal angle for the lesser veins, (whether proceeding from the lateral veins or from the midrib,) and for the lesser branches, including the peduncle. This secondary angle is in some few plants more acute than the primary. 116 TRACES OF ORDER Thus in tlie common dock the primary angle is 60°, and the secondary angle of flower-stalk and lesser veins about 40°. But in most plants the secondary angle is the more obtuse, and helps, when it is so, to give to the tree its out- spreading ajjpearance. Thus in the lime (see Fig. 25) this primary angle is 42 ', and the secondary about 50 ', and in the oak the primary is 50', and the secondary angle about Q5°. The following may serve as examples of the angles of venation and ramification in some of our common plants :* — Plants witu Woody Steuctuee. Deg. Deg. Alder, . . . .50 LaurustLnus, . . . 50-55 Ash, 60 Lime, 42 Bay Laurel, . . . 50-60 Small yeins and branches, 50-55 Beech, . . . 45-48 Maple 40-45 Birch, 30-48 Lesser veins and branches, 55 Box, • .... 60 Mountain Ash, . . .45 Cherry, . . . .50 Oak, large branches, . . 50 Elm, 50-55 Smaller veins and branches, 65-10 Hazel, . . . .42 Rhododendron, ... 60 Holly, 55 Rose, . . . . . 60 Horse Chestnut, . . .50 Sycamore, .... 50-55 Laburnum, . . . .60 Willow, angle varies in each species. Serbaceous Plants. Primary Angle. Secondary Angle. Deg. Deg. Chenopodium glaucum, 40 50 urbicum, . 40 40 Geranium, . 35 j varies in each species, ( in some, 60 Geum intermedium, 30 30 montanum, 35-38 50 Ranunculus, 25-28 differs in each species. Scrophularia aquatica, . 40 50-60 nodosa. 40 50 Sinapsis nigra. 40-45 50-55 Valeriana officinalis. 30 (vein) 45 ♦ We are -wllIiDg to admit that in following out these views, anomalies will present IN THE ORGANS OF PLANTS. 117 We have found that the angle of the peduncle seems specially to correspond to the angle made by a vein coming forth near the top of the main lateral veins. (See a in Fig. 25.) Let us here recall the doctrine pre- viously enunciated, (see p. 95,) that the pistil is a leaf folded on itself, as may be seen very evidently in a pea- jwd.* If we inspect the interior of such a pea-pod, we shall find the seed coming off very obviously from the top of a lateral vein. We now see that in the leaf a lesser vein, bearing seed in the pea-pod, corresponds in the ramification to the peduncle bearing the flower. This completes the correspondence between the leaf and the plant on which it grows. 4. Tliere is a correspotidence heticeen the curve of the vein and the curve of the corresponding branches. — Here we must once more insist that every vein and every branch has its normal curve. We have not been able to express this curve in a mathematical formula, but the eye testifies that it has a mathematical regularity, and that there is a correspondence between the curve of the vein and that of the branch. The parts whoso disposition and direction we have been examining, are those which are chiefly instrumental in giving their normal figure to the plant and its leaf ; and as the part in the leaf has a correspondence witli the part in the branch, it follows that there may be a certain correspondence between the form assumed by the leaf and that towards which the whole tree tends. We use themselves. Thus, in plants with decunent leaves, such as thistles, the dccurrcncy of the leaf seems often to make the angle of the vein wider than that of tlie branch. In the Lomhardy poplar the anfrle of the branches seems to correspond not to the prim.iry but secondary angle of venation. These anomalies will turn out to be as instructive as the more regular phenomena. * Schleldcn, it m,iy be proper to mention, considers this to be a stem pistil. There 1» a point liere, a transition point, at which the correspondence between leaf and brancli becomes very close and visible. 118 TRACES OF ORDER the restricted language, may he a certain correspondence, for there are special circumstances which may modify the forms of leaf or plant, and make them differ from each other. Where the leaves are pinnate — that is, arranged hke the barbs of a feather along a common axis, there is no resemblance between the leafage and whole plant.* This does not prove that leaf venation and branch are not homotypal, any more than the differ- ence between the fore and hind limbs in animals shews that these two parts are not homotypal. And in not a few cases the general resemblance between plant and tree is very visible, as — to take the trees whose outline strikes the eye, and prints itself on the fancy in all our landscapes — in the swelhng lime, and the spreading elm, and the heavy-topped oak ; and trees which stand upon an unbranched stalk, as the sycamore, with sturdy ribs and swelhng chest, and the birch and poplar, with theh coma first rotund, and then tapering gracefully to a point. In not a few plants the correspondence becomes minutely, we had almost said ludicrously, exact, and may be detected in the most trivial particulars. Thus the stems of some trees, such as the thorn and laburnum, are not straight, and the branches have a twisted form ; and in these plants the venation is not straight, and the leafage is not in one plane — in this respect very unlike the beech. But in the beech there is a no less curious correspondence, for the stems take a turn at every node at which they send off a branch, and the mid- * Wo would not speak on this subject wilh confidence, but it seems to us that when the leaf is pinnate, the tree i» decomposite— fh^t is, instead of sending up one main axis (like the beech, the poplar, &c.) fiom bottom to top, it sends oflf in a scattered way, as it ascends branch after branch, till the axis is lost. We have noticed this in ash, mountain ash, walnut, Mahonias, Acacias, and also Ailanthus glandnlosus, Gymnocladus Canad- ensis, Koelcreuteria, Sophora Japonica, and Robinias, (R. pseudo-acacia and R. viscosa,) &c. We have also noticed a frequent, though, we suspect, by no means invaiiable, connexion between the doubly pinnate leaf and the umbelliferous structure. IN THE ORGANS OF PLANTS. 119 rib of the leaf has a simihir zigzag appearance. (See Fig. 2^.) Such points as these should be carefully noticed and attended to by the landscape painter and by the pruner. When the commonwealth of taste is properly constituted, one of its first laws will be passed against the common mode of pruning, which cuts trees into all sorts of un- natural shapes, and in particular, pays no regard to each plant's peculiarity of beauty. We can excuse the old Scotch Earl who planted his trees in groups, to represent the position of the troops which gained a victory under him, for if he thereby spoiled the beauties of nature, he at least imparted some knowledge of military art ; but those who, in ornamental lawns, form spherical yews and conical laurels— those who force plants to resemble beasts, birds, or fishes — those who give the oak or elm a bare stalk — those who cut over a poplar to make it bushy from the base — those who break off the triplet from the broom or laburnum, or deprive the lime, or the chestnut, or the sycamore of its whorl, should themselves, on the prin- ciple of exacting one member for another, be subjected to a similar pruning process, and this because of the ofience which they commit against nature without and nature within them. These observations apply to plants which have leaves veined, unfolded, and presenting a surfiice to the eye. We now turn to plants which have ncedle-sha])ed or linear leaves. Such leaves correspond, we believe, to the individual stems proceeding from the axis or branches. But our observations have been confined to the great family of the Coniferae, so called because their seed- vessels are cone-shaped. In what follows, our illustra- tions are to be taken chiefly from pines and lirs, the 120 TRACES OF ORDER only portions of the large family of cone-bearers which we have had an oi^j^ortunity of carefully inspecting. It is obvious, on the most cursory observation, that a unity runs through the whole of the structure of each of tliis tribe of plants. We may notice first, how the ap- pendages are regularly arranged in a series of whorls (usuig this phrase in the loose sense previously explained) along the whole axis. There is, first of all, a whorling in the arrangement of the cotyledons, or first springing leaves. Some botanists have represented the cotyledons of the Conifera3 as numerous ; others are inclined to think that there are only two cotyledons, and that each of these is cleft into a number of parts ; all agree that the parts are wdiorled. Looking to the axis above ground, we observe the same arrangement repeated in the branches, which come out at the nodes in a succession of whorls from the base to the top of the axis. Every node and internode of the pine is of the same construction as every other. We may notice further, how the whole tree, composed of stem and branches, is made, by the evidently prede- termined arrangement of these parts, to assume in its outlme a most elegant figure. The form is that of the cone, rounded off gracefully at the base. We are aware that in many cases the lower branches, especially if eaten by cattle, fall off as the tree grows old, and show a bare trunk surmounted by a bushy top : thus, when the lower branches of the broad-topped stone pine fall away, we have that picturesque, umbrella-shaped figure, which so often appears in Italian scenery and Italian paintings. But, in its natural and normal shape, every cone-bearer seems to be feathered from near the root. It is interest- ing to notice, that if we were to intersect the tree hori- zontally at any one node, the part cut off above would IN THE ORGANS OF PLANTS. 121 always be a cone, somewhat similar in shape to the whole tree. This, no doubt, results from the nature of the cone as a mathematical fiu-ure ; but on noticino- the fact, we are the more impressed "udtli the peculiar fitness of the pre-arrangement which makes stem and branches produce so perfect a figure. While the whole family affect this general form, we may observe that every spe- cies takes a shape of its own, so that we can at once determine what it is at a considerable distance. Some, like the common spruce fir, have a sharp apex, and look as if they jjointed to heaven ; while others, like the stone jnne, are broad and bushy, and look as if they delighted to embrace and shelter the earth. There is one beauty of the finely-proportioned cluster pine, another beauty of the sturdy Scotch fir, another beauty of the tapering Douglas fir, another beauty of the graceful Weymouth, another beauty of the shaggy Montezuma, and another beauty of the brawny Coulter pine, as he flings out his arms so powerfully. No attempt should be made, by cutting or bending, to make any one species take the form of any other ; all such officious meddling, on the part of man, will only mar the beauty of the Divine workmanship. A lawn is fairest to look on when differ- ent species are planted on it, when each is allowed to grow naturally, and has room allotted to it to shew its peculiar type and beauty. Turning now to the inspection of the seed-vessels, we find them, as their name (cones) denotes, moulded after the same form ; nay, the very clusters or bunches of stamens (amenta) arc made to assume a conical shape. It is evident that, in this tribe of plants, there is a sig- nificancy in this beautiful mathematical figure ; and we are inclined to ask whether it was not some mystic ])Qv- ception of tliis which led the ancient Assyrians to assign G 122 TRACES OF OEDER SO important a j^lace to the cone in those sacred symbols which have become so famihar to us by the researches of Dr. Layard ? But without insisting on this, we think we are justified in affirming that the circumstance that the cones, formed of scales, which are modified leaves, and amenta, which are also formed of modified leaves, taking the same shape as the tree, formed of branches, is another illustration of the tendency of leaf and branch to obey the same laws and follow the same dispositions. Not only is there a general resemblance between cone and tree ; we are inclined to think, from a pretty exten- sive observation, that the full-grown and expanded cone not unfrequently tends to take the shape of the particular species of tree on which it grows. It would require a series of measurements, such as we have not had it in our power to make, to establish this truth scientifically, but a general correspondence is often obvious to the eye. Thus, to take some of the species most marked in themselves, and best known among us. The common Norway spruce is tall in proportion to its width, and so also its cone. (See Fig. 27.) The same may be said of Abies Douglasii, which, moreover, has a sharp apex ; the cone tends to assume the same shape. In striking contrast is the stone pine, (Pinus Pinea, see Fig. 28,) in which both cone and tree are wide in proportion to their height. The cluster pine (P. Pinaster) is beau- tifully proportioned in its length and breadth, both in Fig. 2T.* * Fig. 2T. Cone of Abies excelsa, bearing a resemblance to a tree, and shewing a set of spirals from right to left, ami anotlier set from left to right. These sets of spirals, crossing each other, produce on the surface of the cono rhoni! oi !;il figures. IN THE ORGANS OF PLANTS. 123 tree and cone. (See Fig. 29.) Contrasted with this, both the tree and cone of Piuus puniila have a crushed ap- !?^ (f-^^Sk Fig. 28.* FiG. 29.+ pearance. Coulter's pine has heavy, wide-spreading branches, and its cone is of a rotund, bulky sliape. The cone of the Labrador pine (P. Banksiana) is often bulged at one of the sides, and any of the trees which we have seen have a straggling, misshapen appearance. We now proceed to give the result of a scries of obser- vations:!: in regard to the dispositions of the scales of the cone and the leaves of the tree. (1.) The scales are arranged along the axis of the cone * Fig. 28. Cone of Pinus Pinea; (lanii>y like tlio tree, shewing tlio two sets of spirals crossing each other, and jiroducing rhoiiiboidal tigures, whoso angles are approxiniulely above and below 120° and 60° at each of the sides. + Fio. 29. Cone of Pinus Pinaster, shewing the two sets of spirals, and rhomboids with deflnlte angles. X In making these observations, T)r. M'(jos1i has examined, willi moiu or less care, nearly every cone Intho Museums of Kew, of tlie I.innaan Society, and of tho Edin- burgh Botanic Garden, all of which liavo been kindly thrown open to him. 124 TRACES OF ORDER in a spiral manner. As the basis of the whole, there seems to be a governing spiral — that is, the scales are attached to the axis in a regular spiral. This spiral is at times from right to left, and at other times from left to right, and we have not been able to discover any law determining which of these courses it should pursue ; it certainly is not determined by its position on the tree, or by the course of the sun in the heavens. The scales in this spiral being at equal distances, necessitate mathe- matically other three spirals, or four spirals in all — one of these, the governing spiral, and another, running in the same direction, and other two in the opposite direc- tion. Sometimes all of these spirals can be noticed ; in all cases two are very visible, one from right to left, the other from left to right. (See Figs. 27, 28, 29.) On comparing the cone with the branch, we find a dis- position in the appendages of the latter similar to those of the former. The leaves on the young stem and the scars left when these leaves fall off, form invariably two sets of visible spirals, one from right to left, and the other from left to right. (2.) The two sets of visible spirals form, by their in- tersection, a series of very beautiful and mathematically regular rhomboidal figures on the surface of the cone. (See Figs. 27, 28, 29.) The elegance of the whole figure, with these spiral gyrations, which allure on the eye, and these well-defined lozenge shapes on the surface, form the ground, if we do not mistake, of children's predilection for cones. When they gather these so eagerly and industriously, when they play with them for such a length of time, it must be be- cause of some unconscious perception of the visible har- monies — a perception which they could not of course scientifically expound, or even express to others. And it IN THE ORGANS OF PLANTS, 125 would "be well for us in this, as in many otlier cases, not contemptuously to cast away the simple tastes of our childhood, hut rather to cherish them, and put them meanwhile under the guidance of a matured understand- ing. A pine-cone will reward the study for hours toge- ther of the very highest intellect. Here, as in numerous other instances, science, in following up our spontaneous tastes, will unfold wonders on which the reason gazes Avith profound interest. If we measure these rhomboidal fio-ures on the surface of the cones of pines and firs, we find that the angles are definite, being approximately 120° above and below, and 60° at the sides. (See Figs. 27, 28, 29.) We use the language approximately, because there is often, as might be expected, a departure from the normal angle on the one side or the other, but the actual angles stick so closely, on the one side or other, to the numbers given, that we may regard these as the normal ones. The eye, or rather the intellect, feels a pleasure in contem- plating such a figure, made up of two equilateral triangles, and in every respect so beautifully proportioned, and com- bining an easily observable unity with an easily observable variety. On the stems likewise, the intersection of the two spi- rals formed by leaves, and the scars of fallen leaves, forms a scries of rhomboids. We cannot speak so confidently of the angles of these rhomboids as of those of the cone, but we have found in many cases that when the leaves have fallen oif and the scars are visible, tlie angles at two of the opposite corners are approximately 120", and at the other two opposite corners 60°. But there is this difier- ence between the rhomboids on the cone and the rhom- boids on the stem, that wliereas in the former the angle is 120° above and below, and 60° at the sides, in the 126 TRACES OF ORDEE latter the angle is 120° at the sides, and 60° above and below. We have found these numbers very often on the stem of a few years old ; as it becomes older the rhom- boid is less elongated, but by this time the scars are be- ginning to disappear, being covered up with the bark. This arrangement produces on the surface of the cone a series of quincunxes, a figure which has long been re- garded as possessing many virtues. Virgil, in his Georgics, in giving directions for planting trees, says, " Indulge or dinibus," and recommends the quincunx. " Omnia sint paribus numeris dimensa viarum, Non animum modo uti pascat prospectus inanem, Sed quia non aliter vires dabit omnibus sequas Terra." ViRG. Georg. II., 284-286. Speaking of the same figure, Quintilian says, " Quid quincunce speciosius qui in quamcunque partem specta- veris rectus est." Sir Thomas Browne, in his ingenious though fanciful work, entitled " The Quincunx Mystically Considered," seems to have had pleasant glimpses of the truths to be discovered by the study of the cone-bearers, " Now, if for this order we affect coniferous and tapering trees, particularly the cypress, which grows in a conical figure, we have found a tree not only of great ornament, but, in its essentials of affinity unto this order, a solid rhombus, being made by the conversion of two equicru- ral cones, as Archimedes hath deponed. But these were the common trees about Babylon and the East, whereof the ark was made." " But," he adds, " the Firr and Pine Tree do naturally dictate this position ; the rhomboidal protuberances in pine-apples maintaining this quincun- cial order into each other, and each rhombus in itself. Thus are also disposed the triangular foliations in the IN THE ORGANS OF PLANTS. 127 conical fruit of the Firr tree, orderly shadowing and pro- tectino; the winsred seeds below them." (3.) There is, we have said, a very visible set of spirals going from right to left, and another very visible set from left to right on the surface of the cone. In these sets there is a definite number of spirals. We j)i'opose, in the absence of an authorized word, calhng the parts or numbers of a set of spirals, threads. The number of threads, in a set of spirals in all conifer;i3, seems some one of the following numbers, 1, 2, 3, 5, 8, 13, 21, 34, &c., in which scale any two contiguous numbers added together gives the succeeding one. We have already fallen in with this remarkable series of numbers in leaf aiTangement ; it now casts up once more in a somewhat different, and probably a more fundamental relation. In the case before considered, these numbers were merely the more common ones ; in the case now before us they seem to be invariable ones. On the supposition that the spiral, more or less modified, governs the an-angement of the appendages of all plants, we are inclined to look on this series as having a deep significancy in the morj)ho- logy of the plant. We have observed that there is a constant relation in the number of threads in the two sets of spirals. What- ever the number of threads in the one set of spirals — say that proceeding from right to left — the number in the other — those proceeding from left to right — is always one or other of the contiguous ones in the above scale. The number of spirals in the two intersecting sets are 1 and 2, or 2 and 3, or 5 and 8, or 8 and 13, or 13 and 21, or 21 and 34. Thus, if the number of threads in the one set of spirals — say that proceeding from right to left — is 5, the number in the otlier set — that proceeding from left to right — will be either 3 or 8. Tliese nume- 128 TRACES OF ORDER Fig. 30.* rical relations seem to regulate the sets of spirals in all coniferj©. In pines the number of threads in by far the greater number of species, is 5 and 8. In a few species the numbers are 3 and 5, and in a few others 8 and 13. In Arancauria imbricata the number of threads in the two sets respectively is 21 and 34. In the disposition of the scars on the stems there are similar numerical relations. Thus the number of threads is one or other of the num- bers in the scale, 1, 2, 3, 5, 8, &c., and the numbers of the two sets are always contiguous ones in this scale. Thus, if the number of threads in the one set of spirals is 3, the number in the other will either be 2 or 5. We have remarked, however, that the number of threads in the spirals of the branch is commonly less or lower in the scale than the number of threads in the spiral of the cone. In pines the common numbers for the cone are 5 and 8, whereas the numbers for the visible spirals on the stem are 5 and 3. (4.) We have found in the cones of pines and firs, (so far as we have examined them,) that all the spirals in one of the sets, and this invariably the one which con- tains the greater number of threads, take approximately just one turn in going from the base to the top of the cone, that is, each goes round the axis once, and stops at the apex perpendicularly over the point from which it * Fio. SO. Diagram shewing that two sots of spirals set out from the base of a cone, and that there is a relation between the number of spirals in the two sets. In tiie dia- Kiam the number proceeding from left to right is 5, and the number from risfht to left is 8. IX THE ORGANS OF PLANTS. 129 started. Tims, if the spirals -be 8 and 5, (as in Fig. 30,) then each of the 8 will be found to have taken one complete turn before it reaches the apex, and if the numbers be 13 and 8, the 13 will be found to have twisted themselves once round the axis. This seems to be the rule followed by the set of spirals containing the larger number. The other set appears also to have a rule. In cones with the ordinary relation between the height and width, that is, where the circumference is greater than the height, the number of turns made by the set of spirals of the lower number is 2, that is, the spirals go twice round the axis before reaching the apex. But in cones whose height is great in proportion to their width, whose length is greater than their circumference, as, for example, Pinus Strobus, Pinaster, excelsa, monticola, Lambertiana, filifolia, and Abies alba, excelsa, Douglasii, the number of turns taken by the spirals is 3. Such co-ordinated facts as these may possess little interest to the mere technical naturalist, whose sole aim is to discover new genera and species, or the mere prac- tical horticulturist or arboriculturist, whose object is to find plants of commercial value. But they tend to raise up profound reflections in the truly philosophical mind, and open uj) glimpses to the religious mind of the dcei") things of God. They shew that the plant, and all its members, had been before the mind of God prior to the time when He said, " Let the earth bring forth grass, the herb yielding seed, and the fruit-tree yielding fruit after his kind, whose seed is in itself upon the earth, and it was so ;" " and God saw that it was good." Mathe- matical figures, more or less modified to suit special ends, make their a])pearance everywhere among the members of tin; jilant. The mathematical spiral regu- lates the arrangement of all the appendages of the jilant. 6* 130 TRACES OF SPECIAL ADAPTATION Even the lines which man has not been able to express in mathematical formulfe, such as the cm-ve of the veins and branches, and the outline of the coma of a tree, are evidently regulated by models in the mind of the Divine Architect. Numerical relations of a most interesting character cast up among every class of plants, and among all the organs of every plant. All appendicular organs, whether belonging to the nutritive or reproductive sys- tem, are homotypes. Nay, correspondences may be detected between the disposition and the distribution of branches and leaf veins, sufficient to entitle us to repre- sent root, stem, and leaf, as homotypes, and to prove that there is a unity of composition in the structure of the whole plant. SECT, II. TRACES OF SPECIAL ADAPTATION IN THE ORGANS OF THE PLANT. Our aim in this chapter is to shew that in the struc- ture of the plant there are combined simplicity of general plan and variety of modification, the latter for special ends. Having endeavoured in the preceding section to demonstrate the first great truth, we are in this section to illustrate the second. It is evident that stem and common leaves would not suffice to fit the plant for the discharge of all its func- tions. It needs, among others, organs or appendages for covering, for support, and for enabling it to propagate and perpetuate itself. To meet these wants members are found to spring up at the very place where they are needed, and at the very time when they are needed ; and when they appear they come not as absolutely new organs, but after the old type, modified to serve the present purpose. Does the plant demand a covering ? — IN THE ORGANS OF THE PLANT. 131 the leaf becomes a scale, or the cuticle .produces hairs for that purpose. Is defence required against external attack ? — leaves or branches become sharpened or hard- ened at the poirit, and the whole plant, or the more assailable parts of it, are bristled all over with spines or prickles. That the species may live on in a new indi- vidual, the leaf takes a yet greater departure from its type, and becomes a stamen or pistil. The general plan of the Great Architect is kept up, and yet every several member fulfils a purpose. We capnot conceive of stronger or more convincing evidence of design being supplied to human intelligence. 1. ORGANS OF VEGETATION. The general structure of the leaf has been already described ; we are now to contemplate some well-marked special modifications. The cuticle, or skin, shews nume- rous small openings, (the stomata of botanists ;) these, like the holes in a barn, keep up the communication between the air and the interior. In the leaves of aerial plants, which have the usual horizontal position, these pores are commonly abundant upon the lower surface, and upon that under surface the skin is also of a more delicate nature ; on the upper surface the stomata are usually less numerous, or even, in some cases, wanting, while the skin is tougher and denser. In leaves, again, which float on the surface of the water, the openings are confined to the upper surface, and in submerged leaves they are wanting altogether. The intervening portion of the leaf, already. described, called ])arcnchyma, presents some remarkable peculiarities in relation to the pores we have been describing. Next the upper surface of the leaf, it consists of compact oblong cells, placed per- pendicularly and in close contact with each other, the 132 TRACES OF SPECIAL ADAPTATION layer nearest the 'lower surface is less dense, and nume- rous vacant spaces occur between the cells, permitting free communication, through the stomata or pores, between the atmosphere and the interior of the leaf We have here, therefore, a striking example of harmony between the struc- ture of this part of the plant and its function and po- sition. The pores are exhaling and absorbing organs ; Fig. 31.* wherc they are most abundant, there we lind loose texture of the parenchyma, permitting free communication ; where stomata are not needed, they are wanting ; when they are required on a particular part of the leaf, there we find them. Many species of Utriculariae — delicate water-plants — have nu- merous small sacs connected with the leaves, which are stated, about the flowering period, to become filled with air, and to buoy the plant near the surface of the water. In Pontederia crassipes and Trapa natans, some of the leaves have the stalk dilated into an air cavity, which acts as a float. The magnificent Victoria Regia presents several interesting features. It is an aquatic belonging to the water-lily family, and the fully developed leaf reaches a diameter of five feet or more. In order to give strength to such a large surface, the veins on the lower aspect of the leaf are of great depth, acting as so many * Fig. 81. I'eiT)eudicuIar section of leaf, to shew different structures of upper and lower portions. IN THE OKGANS OF THE PLANT. 133 supporting girders. Between tliem are formed spaces in Avhich air might accumulate and lead to a rupture of the parts ; such an occurrence, however, is obviated by the perforations which constitute one of the pecularities of this remarkable plant. By transmitted light the leaf resembles a sieve, with numerous minute openings. Stipules. — These appendages assume different forms, and vary in size and texture, according to the plant in which we examine them. They are, as already stated, formed after the leaf type, and although we cannot, in every case, point out the purposes served by their modi- fied form, there are, nevertheless, instances in wliich we cannot doubt that they are present for a useful object. In Lathyrus aphaca they are of large size, and supply the place of the leaves, which are absent in the mature plant. In not a few plants they perform important functions as protecting organs, forming a covering to the young leaves ; this is obvious enough in Magnolia, in the Indian-rubber fig, and in the submerged Pota- mogetons. When the leaves expand, these protective stipules fall off ; their function being performed they are no longer needed, and so they disappear. Covering of 2')lants. — The varied aspect of the external surface of the different organs of plants, so important to the botanist in the distinction of species, and designated by the terms downy, silky, scaly, &c., is owing to the presence of certain minute appendages, the nature of which has been already described. (Sec p. 86.) In cer- tain cases their presence has some relation to the habitat or dwelling-place of the plant. Those on the upper part of the pistil of hare-bell are well-known to act in col- lecting and retaining the pollen grains as they drop from the anther. There can be no doubt that in many cases the very minute fibrils on the underground parts 134 TEACES OF spj:cial adaptation of plants, whicli assist in the jDrocess of absorjotion, are really hairs, and of the same nature of those which cover aerial organs. Armature. — Plants, like animals, have been provided with organs of defence, varying in strength and in the effects left by them from the simple and almost innocu- ous prickle of the rose to the formidable sting of Urtica urentissima, the wounds inflicted by which often lead to dangerous or even fatal results. We have shewn in last section that under the term xirmature are comprehended modifications of several parts. The spines of the white Thorn and the black Thorn, of which every one has had experience, are branches turned into spear points, to repel all sensitive assailants. In Barberry certain leaves have been sharpened into prickles ; in Holly the leaves have had their secondary veins hardened and pointed effectually — as the mouth of any animal which may at- tempt to eat them will testify. In Eobinia the stipules have undergone a change of condition, to fit them for a similar defensive function. The armature of Nettle and Loasa are modified hairs, as are also the prickles of the rose, and many other plants. Supports. — This term comprises various modified organs, supplying instances of design as palpable as any furnished by the pillars and buttresses of human archi- tecture. The native tendency of the stem is upwards, but there are multitudes of plants too weak to retain their vertical position ; and to aid them in their heaven- ward inclination various provisions have been made. At times the stem itself becomes twined round other plants ; this spiral twining may either be from right to left, as in the French bean. Dodder, Convolvulus, &c. ; or from left to right, as in the Honeysuckle and Hop. At other times the same end is accomplislied by the superficial I IN THE ORGANS OF THE PLANT. 135 appendages of the stem, as, for instance, by tlie mmiito hooks on some species of Galium, Tendrils, varying, as we have seen, iu their nature in different plants, but all really referrible to a common type, possess the same properties as twining stems ; they twist themselves round other plants, and thus support species too weak to stand in their own strength. In Dischidia Kafflesiana the piYc/icr-shaped organs are leaves whose margins have become adherent. This plant is a climber, sometimes reaching the top of the loftiest trees, and generally the pitchers are confined to its upper l)art. It is stated that there, small roots are developed, and these, entering the pitchers, absorb the fluid which is accumulated from the fall of rain or dew ; the iQng strag- gling stems are thus j)rovided Avith a means of receiving nourishment at both extremities. In human architecture we may discover contrivance in the means taken to retain the general symmetry of the entire edifice, while at the same time every part of it is devoted to a useful purpose ; and surely the ex- amjiles we have given indicate the same kind of lofty design, contriAdng to make organs conform themselves to a general type while they accomphsh particular ends essential to the wellbcing of the ])lant. The cases brought forward belong to the nutritive system of plants ; similar examples are furnished by the reproduc- tive economy. But before proceeding to examine these, Bracts may be alluded to, as forming an evident tran- sition, as we have already shewn, from leaf to sepals, or divisions of the calyx. They are leaves specially modified, and may help the parts of the flower in the performance of their office. This may be laid down as a general rule, though we may not be able in every case to specify with precision their peculiar function. There are very 136 TRACES OF SPECIAL ADAPTATION numerous cases in wliicli they serve as protecting organs. In Palms, and other plants, the large sheath which they form, called technically a spathe, encloses numerous flowers as yet in an early stage of development. In some Palms it is calculated that there may be thus protected no fewer than 200,000 flowers. In Narcissus, Allium, &c., the bract forms a protecting sheath to the flowers while in a young and tender state, and when these expand it shrivels and decays. In the daisy, and others of the family Compositaj, the numerous florets are protected by one or more series of overlapping bracts. The cup of the acorn is a protecting organ, formed also of numerous overlapping organs of the same nature. Where these parts present much resemblance to leaves, they often, as in Anemone and other plants, serve at first as protecting appendages, and subsequently they aid the leaves in their all-important functions. II. REPRODUCTIVE SYSTEM. Calyx.— It is admitted on all hands that the sepals, or pieces of the calyx, though not present in every instance, and therefore not absolutely essential in the economy of the flower, do, when present, perform some good offices. This is true, whether the pieces, in consequence of lateral adhesion, are made to take a tubular shape, or whether they have some other form. There can be no doubt that, in numerous instances, this part not only pro- tects the more internal organs, but likewise assists the leaves in their function. The remarkable, and often very beautiful, hair-like appendages of the fruit (part of the calyx modified), in Composite plants, as the dandelion and others, assist in the dissemination of the fruit and seed : acted on by the wind, these pappose fruits are wafted to a distance from the parent plant, and, when IN THE ORGANS OF THE PLANT. 137 they fall into a suitable soil, become the parents of fresh colonies. Corolla. — The general office of this organ is very obvious. This whorl of petals serves, in most cases, to support and protect the more vital organs within ; such, at least, is one function which it evidently performs. It is all true, that we cannot in every instance state, Avith a well-founded confidence, what connexion there is between the form and colour of the individual piece or " of the entire corolla, and its use in the economy of the plant. In not a few vegetable organisms, both calyx and corolla are wanting, and in such cases, at least, they cannot be essential organs ; but when present, we may believe that they serve a purpose. It is supposed by some that there is a relation between the colour of the petal and the measure of heat which it absorbs, and which the flower requires. Possibly there may also be a relation between the form of the corolla and the process of seed or fruit production in the species ; but science is not yet prepared to point it out. The brilliant apparatus of the flower acts, we are comdnced, as an attraction to various kinds of insects, which, in the act of procuring food for them- selves, assist also in scattering the fertihzing pollen, and bringing it into contact with the upper part of the seed- vessel. If we need to seek for any other final cause, we shall find it in the shapes and colours of flowers, as ad- dressed to that love of the beautiful which is one of the most bountiful parts of the wonderful constitution of our nature. Stamens. — These, with the pistil in the centre of the flower, are the most essential organs of all. Tlieir all- important office is to ])r(jduce the pollen or fecundating powder necessary to the formation of the seed. We have pointed out, in last section, the ]i()ini>logy of 138 TRACES OF SPECIAL ADAPTATION the stamen and its parts. Its departure from the gene- ral type is not so great as might at first appear, still it does deviate widely from the leaf, and all to accomplish the very special end allotted to it. The filament which supports the anther is (wo have seen) no more essential to that anther than the stalk is to the leaf. This fila- ment, however, does at times assume forms which act an important part in relation to other organs and the gene- ral mechanism of the plant. Thus in Kalmia, each anther is kept back by a little hood or hollow in the part of the corolla opposite to it. A slight force — the touch of an insect, for example — suffices to release the anther, when the elastic filament, acting as a spring, brings it forcibly in contact with the upper part of the pistil, the pollen meanwhile being freely emitted. The same object is secured by the elastic filaments of the common nettle, and the irritable filaments of the barberry. Without entering more minutely into the subject, it may be ob- served generally, that the application of a fertilizing matter being absolutely necessary to the propagation of the plant, it appears precisely where it is wanted ; the parts which produce it j)rotect it in the first place, and aid in the final application of it ; while the whole appa- ratus is a special modification of the typical member. Fistil.—lLh.G leaf type is here modified to form an all essential organ. Its functions are to receive and retain the pollen, and the top of the stigma is admirably fitted for such purposes. Another part of the same organ con- ducts the fecundating matter to the seed-buds or ovules, and affords also to these vital members protection — of a more temporary or permanent kind — till such time as they attain maturity, and reach a locality in which they may germinate into new life. In not a few cases the seed-vessels have appendages which act as wings, and IN THE ORGANS OF THE PLANT. 139 ■waft them by the aid of the wind to distant locahties. In other cases the appendages become floats or protec- tors, and give us nuts and capsules, which are conveyed by rivers and ocean currents to establish new colonies far from the parent stock. The hooks and other aj)pendages of some fruits make them adhere to the coats of animals, and thus the plant, stationary itself, has its seed disse- minated wide as the range of the animal, with its feet and wings. Other instances are not wanting of evident adaptations in the general structure of fruits, and in the properties of their elementary tissues, Tlius the ripe fruits of some species of balsam, when touched, suddenly burst and scatter the seeds with considerable force ; the squirting cucumber is a still more remarkable case of the same description. Another final cause, different in kind, comes into view very prominently at this place. He who makes every organ subserve the welfare of the plant, has also made the plant, as a whole, and its individual parts, to pro- mote an ulterior end. It seems very evident to us that certain modifications of the organ under consideration, and others contiguous, have a direct reference to the wants of man and the lower animals. We never can believe that the sugar, acids, oils, starch, and other pro- ducts formed so abundantly in the fruits of difiercnt plants, were not meant to serve as food, and afford sen- tient gratification to the animal creation. The fruit, in its earlier stages, performs a necessary part in fertihza- tion, at every period it yields support and protection to the young as well as tlie mature seeds, and when, in ad- dition to these, it presents its beautiful forms and colours to the eye of man, and pleases all sentient creation with its perfumes, and gives satisfaction to the i)alate, and nourishment to the frame, we are sure that we have be- 140 TRACES OF SPECIAL ADAPTATION fore us the modification of an organ for a twofold pur- pose, the one bearing directly on the economy of the plant itself, and another, and a further, having a respect to the wellbeins: of the animal world. And these ends, be it observed, are accomplished in conformity with the grand regulating principle of type or pattern. In a ripe cherry the kernel is the seed ; the hard stone, so admirably fitted for protection, corresponds to the upper cuticle of the leaf — thus singularly transformed for a useful end ; the skin of the fruit represents the cuticle of the lower surface of the leaf ; the intervening delicious pulp is just an expansion of the cellular sub- stance previously described as lying between the two cuticles ; nay, the observant eye will discover that in the line on one side of the cherry, we have the united edges of the typical leaf. ■ Finally, in the Seed itself, that portable epitome of the entire vegetable organism, we find differences in the relative development of different parts, all in decided re- lation to some special function which has a respect to the continuance of the species, or the necessities of the ani- mal creation. We have alluded to the adaptation of certain parts of fruits to the purpose of protecting the seed ; but the seed itself has often an independent means of resisting injury in its hard integument or skin, modi- fied for that purpose. The wing-like appendages of pine seeds, and the abundant hairy covering of those of wil- lows, doubtless aid in their dissemination when they are committed to aerial currents. It may be added, that man finds in the covering of the seeds of the cotton plant an economic product of immense value for his clothing and comfort. For the better comprehension of special modifications in the seed itself, we would refer to previous remarks, IN THE ORGAN'S OF THE PLANT, 141 (p. 82.) Generally speaking, we find two obvious con- trasts in the relative development of the internal parts, viz., large cotyledons, and the albumen small or absent, {Fig. 8,) and small embryo with copious albumen. In the economy of each individual seed these differences are of vital importance. In germination the cotyledons in some cases (as Lupine) rise above ground, assume a green colour, and, for a time, perform the functions of leaves, finally giving place to the true leaves of the new plant, when these have attained suflicient size ; or the cotyle- dons may remain under ground during the process of germination, as in the i)ea and bean, yielding up to the young plant the store of nourishment which they contain. Seeds with copious albumen and small embryo have, in like manner, in the former a temporary store of food for the latter. But further, those parts of the seed which are of such importance in the early economy of the young plant, pre- sent also a new relation, viz., to the existence and well- being of man and numerous lower animals. Starch, oil, &c., are products yielded in abundance by seeds ; and the hard albumen of some, as the ivory-nut, is turned to a useful purpose in the arts. To sum up what we have said : — The stem bears up the whole plant, so that the influence of the sun and atmos- phere may act through the leaves upon the fluids absorbed by the roots ; which roots perform the functions of stays, enabling the whole vegetable organism to resist the action of such physical agents as wind. The law of the spiral, which regulates the arrangement of tlie ai)pendagcs, seems to be admirably calculated to expose them to the influences needful in order to the growth of the whole plant. Cer- tain of the si)ecial modifications are either absolutely necessary to the existence of the plant, or tend to its 142 TRACES OF SPECIAL ADAPTATION wellbeing, such as tendrils for support, scales and hairs for protection, spines and prickles as armature for de- fence. We also know that some of the varied modifica- tions of the floral organs, namely, the stamens and pistils, arc essential to the continuance of the race. It is very evident, too, that regularity in the arrangement of the flowers and of their parts will promote the function of fecundation, and tend to lessen risk of failure in this imjoortant end. Even the more common arrangements seem as if they were intended to promote the fertihzation of the seed. Thus the stamens of the upper flowers of" a spike, (wheat, for instance,) or of a raceme, (as common currant,) may not only fecundate the ovules in the flower to which they belong, but are also well placed to insure the fall of the pollen on those which stand below them. In the spikes of some species of carex or sedge, where the stamens and pistils are often in separate flowers, those at the apex of the spike have stamens only, and those further down pistils only. Again, when species of carex have some spikes with stamens only, and others with pistils only, the former often stand highest. These cases are so uniform and so numerous that we cannot regard them^ as mere accidental coincidences. There are, no doubt, exceptions, but in all such cases the same end is accomplished by the insects which frequent flowers in search of food, scattering and conveying from one flower to another the fecundating pollen. Again, the regular arrangement of the ovules in the interior of the seed-vessel, will be more likely to give each a better chance of receiving the influence of the matter conveyed by the minute tubes which pass down from the pollen, than indiscriminate jumbling of the whole. Thus we observe in the vegetable kingdom that special ends are served both by the typical organs and IN THE ORGANS OF THE PLANT. 143 their distribution, and also by the numerous deviations from the typo, whatever be the nature and extent of these. It must, however, be frankly acknowledged that we cannot in every instance discover a final cause for every particular part of every plant, or, at all events, that our present knowledge does not entitle us to speak confidently on the subject. But this is not necessary in order to the validity of our argument. In a building we may be able to recognise design in its general style, although not in circumstances to point out the special purpose which every part of it was intended to serve. On the same principle we believe that we are entitled to say that we have discovered marks of design in the plant as a whole, and in its various modifications, even when we may not have arrived at a stage of knowledge which enables us to understand why an organ has assumed one 2:)articular form rather than another. It would be a very limited range of contemplation if our attention were confined to the function which individual parts are intended to perform in the vegetable economy. We cannot doubt that there is a relation between the existence of plants and the support of the animal world. In the grass of the field, and the valuable products yielded by fruits and seeds, we can see a provision made by the Creator for supplying the necessities of His creatures. We go a step further, and afiirm that plants were meant not only to furnish food to the animal creation, but were intended to afford them pleasure by their tastes and by their perfumes. It will surely not be affirmed (hat the organs of taste and of smell were given us merely as means of procuring food, or as sentinels, on guard at the outposts, to warn us of danger. Plants might have Ix rn less sapid or less odoriferous without any derangement of 144 TRACES OF SPECIAL ADAPTATION the functions wliicli each part fulfils ; and there is surely- some ground for concluding that He who planned and made them all superadded those qualities, and instituted a harmony between the sensate and the insensate, for the gratification of animal tastes. Not only so, we think there is good ground for affirming that not a few vege- table forms were meant to gratify the ajsthetic feelings of man. We cannot declare with certainty that the forms assumed by the flower, by its calyx and corolla, are in every case necessary to the functions of the plant. We will not affirm that the beautifully rounded form of the I^each, the delicacy of bloom on the surface, and the dehciousness of its flavour, are required in order to the production of the kernel and its hard protecting sheU. We have no reason to think that the brilliant scales on the wings of the butterfly are necessary to its flight, for the insect, (as any one may observe) can fly after they are mostly all rubbed off, and some Lepidoptera have few or no scales at all ; and just as little ground have we for affirming that the jolant could not fulfil its ' functions even though the flower had not been so orna- mented. Man has aBsthetic tastes implanted in his nature ; these are gratified to the full by the lovely forms pre- sented in the vegetable kingdom, and we are convinced that all this was arranged by Him who conferred on man his love of the beautiful, and supplied the objects by which that love is gratified.'-' And here we have to express our regret that philosophers have not been able to agree upon a theory of the beautiful. If there had been any acknowledged doctrine on this subject, * Some insist that, tliorc is not only the beautiful in plants, (antl in animals as well,) but also the ^Totesque. Grantcnl, but surely we have here a further example of final cause in the relation between tlie grotesque in the plant and the sense of the ludicrous in man. IN THE ORGANS OF THE PLANT. 145 there would have been little difficulty in shewing that jDlants are fashioned in accordance with a very high style of beauty. In particular, we are as yet without any generally received principles in regard to what con- stitutes beauty of form. In such circumstances we can appeal to no admitted rules, but we can appeal to our own feelings, which declare that the plant, in its general form, and in its corolla, exhibits perfect models of beauty. Here we have an all-suffi.cient final cause super- added to aU the other final causes, bearing more directly upon the economy of the plant, and coming in at the parts, such as the flower and fruit, where these others, to our eyes, might seem to fail. CHAPTER III. THE COLOURS OP PLANTS. SECT. I. THE RELATIONS OF FORM AKD COLOUR IN THE FLOWER. It is a very common impression that there is no rule, no law, for the distribution of colours in the vegetable kingdom.* We are convinced that this is a fundamental mistake. Little, it is true, has been done to establish scientific principles as to the colours of plants. StiU, there is reason to believe that system prevails here as in every other department of nature. Laws in regard to the form, structure, number, and position of organs, are familiar to every botanist ; and it is surely not unreason- able to expect that order may also be found in the placing of colours. One of us has been able to furnish a con- tribution to this branch of inquiry, by discovering evi- dence of a very curious relation between the form and colour in the corolla in plants.f In order that this may be understood, it will be neces- sary at this place to explain certain technical terms used * We arc great admirers of Mr. Euskin's intuitional power, but the following state- ments in his Lamps of Architecture are too unguarded: — "The natural colour of objects never follows form, but is arranged on a different principle ;" and again, " Colour is sim- plified where form is rich, and %Kce veTsa ;"'' "In nature," ho further says, the "boun- daries of forms are elegant and precise; those of colours, though subject to symmetry of a rude kind, are yet irregular — in blotches." t See Dr. Dickie's Papers in Sectional Reports of Proceedings of British Association, 1S54; and Annals of Natural History, Dec. 1854. COLOUR IN THE FLOWER. 147 hj botanists. The term regular is applied to every calyx or corolla in which each sepal or petal is of equal size and of similar form ; in other words, in which all the divisions (whether they are free or adhere to each other by their edges*) are equally and uniformly developed. Every flower in which there is unequal or irregular de- velopment of sepals and of petals, is called irregular. It is to the very great difterence in these respects that we owe the variety of aspect in the flowers of different species. As examples, the following familiar plants may be adduced ; — the pansy has an irregular flower, that of wall-flower is regular ; a primrose has a regular flower ; a snapdragon presents an example of irregu- larity. The following conclusions appear generally to hold good as to the relation of form and of colour in the flower. 1. In regular corollas the colotir is uniformly distri- buted tvhatever be the number of colours present. — That is to say, the pieces of the corolla being all alike in size and form, have each an equal proportion of colour. The common primrose is an example where there is only one colour. In the Cliincse primrose the same holds where two colours (the one the complement of the other) are present, the eye or centre being yellow, and the margin purple ; these two colours in this regular flower are uni- furmly diffused, that is, each piece has an equal proportion of yellow and of purple respectively. In Myosotis, Anagal- lis. Erica, Gcntiana, Pyrola, &c., we have uniform corolla with uniform distinction of colour. All Corollifloras Exogens with regular flowers are examples ; the same is true of certain Thalamiflorte, as PapaveraccfB, Cruciferse, ♦ It may be necessary to explain that the terms free or adherent, refer to the condi- tion of the mature flower, and not to the mode of development. 148 TEE RELATIONS OF FORM AND &c. ; Calyciflorar-'-" Exogens with regular flowers, as Ko- saceee, Cactacete, &c., illustrate the same principle. 2. Irregularity of corolla is associated with irregular distribution of colour, loliether one or more colours are present. — In irregular flowers where the number five pre- vails, the odd piece is most varied in form, size, and colour. When only one colour is present, it is usually more in- tense in the odd lobe of the corolla. When there are two colours, one of them is generally confined to the odd piece. Sometimes when only one colour is present, and of uniform intensity in all the pieces, the odd segment has spots or streaks of white. A i&w familiar instances may suffice. Commou Laburnum, ] ^^^'^ P^*^^^ ^^^^^^ ^ ^^^^'^ y^^«^' ^^^^ ' purple veins. Trifolium pratense, (com- ) Odd piece distinguished from the others men red-clover,) ) by its darker purple veins. Kennedia monophylla, -j ^''"'" P^^^'^^ J'^^^^^i ^^^^ ^^^^^w «y« ^""^ ( purple margin. Swainsonia purpurea -j ^o""" P^*^^« yellow; fifth, white eye on { purple ground. Ajuga reptans, (common ) Four divisions purple ; fifth, has yellow bugle,) ) spot on inner surface. Thymus Serpyllum, (wild ) Corolla generally red purple ; two pale thyme,) ) spots on the odd piece, Galeopsis Tetrahit, j ^°"5 divisions generally yellow; fifth ( piece has purple spots on yellow ground. Euphrasia oflficinalis, (com- ) Corolla purple generally ; odd piece has mon eyebright,) ) yellow spot. In those well-known annuals, Colhnsia and Schizan- thus, the prevailing colour is purple ; the primary, yel- low, appears in the odd lobe. * Thalamiflor* comprehends plants in which there is no adhesion between the whorls of the flower. Calyciflorre comprehends those in which there is such adhesion. In Corollifloi-ie the petals are united by their edges fonnlng a tubular flower, to the Inside of which the stamens partially adhere. COLOUR IN THE FLOWER. 149 In some genera with irregularity of flower often less marked than in previous examples, it is w^orthy of notice that the two divisions on each side of the odd lobe fre- quently partake of its characters as regards colour, half of each resembhng the odd piece, as may he seen in Viola, Gloxinia, Acliimenes, Hhododendron, and other plants. 3. In certain Tlialamijlorous Exogens loith unequal corolla^ arising chiefly from difference in size of the petals, the largest are most highly coloured. — Common horse-chestnut may be mentioned as an example ; on eacli petal there is usually a crimson spot at the lower part ; the size of this spot and its intensity are in direct relation to the size of each petal, the two upper being largest, and the two lateral smaller, and the odd piece least of all. 4. Different forms of corolla in the same inflorescence often 2^^'cscnt differences of colour, hut all of the same form agree also in colour. — The family of plants called CompositJB, comprehending Aster, Cineraria, Daisy, «fec., &c., presents illustrations of this. When there are two colours, the flowers of the centre, usually of tubular form, have generally one colour of uniftn-m intensity ; those of the circumference, having a different form, agree toge- ther in colour also. Thus the common daisy has all the tubular flowers of the centre yellow, and all the ligulate (strap-like) flowers of the ray or circumference are white, variegated with purple. A yellow centre witli a ])uri)le ray is a common association in Comjjositte ; for instance, in species of Aster, Rudljeckia, &c. These principles or laws prevail as well in monocotyledons as in dicoty- ledons. In tlie former, the calyx and corolla generally resemble each other in structure and shape, and in colour also. This very close resemblance between the two 150 THE RELATIONS OF FORM AND whorls has given rise to the idea that there is only one series of external j^arts in monocotyledons. Eelative po- sition must, however, not be overlooked, and hence it is concluded that both calyx and corolla are present. In dicotyledons we generally find a greater contrast between calyx and corolla as regards colour. , We may say there- fore, — 5. The laio of the conti-asts in the colour of thefiower is simpler in monocotyledons than in dicotyledons. — The flowers of dicotyledons may be symbolized by the square or pentagon, four and eight, five and ten being the prevalent numbers in the different whorls ; whereas since three and six are generally found in the flowers of monocotyledons, the triangle may serve to symbolize such arrangement. Such comparison is not fanciful on our part, but an actual statement of the mode of illustration adopted by botanists. Thus, in a work by one of the highest authorities of the day,* a series of triangles is used for the purpose of demonstrating, more clearly than could be done by any other means, the true relations of the flower in the families of the grasses, jialms, and or- chids. We may state in conclusion, therefore, that simplicity of figure corresponds with simpler contrast of colour in the monocotyledons, ivhile greater complexity of colour and greater complexity of structure are in direct relation in dicotyledons. — In all these remarkable co-existences there is surely something more than mere casual coinci- dences. As the laws of the beautiful have not been detected and unfolded, it is not possible to demonstrate scientifically that the relations we have been treating of are in accordance with sesthetic principles. But the eye at once perceives in regard to some of these arrange- * Lindley's Vegetable Kingdom, pp. 109, 169, 178. COLOUR IX THE FLOWEK. 151 ments, that tliey tend to enhance the beauty of the plant. Would not reason be oftended if uniform flowers had not uniform colouring ? Is tliere not a propriety, when in an irregular flower there is one petal standing by itself, that that petal should have more brilliant colours, that thus the flower may bo tempered together, having more abundant honour in the parts which lacked, that there be no schism in the plant ? We are persuaded that were we to put a flower without any colour into the hands of a skilful colourist, and ask him to put on the colours, he would do so on the very j^rinciples according to which plants are coloured in nature. Proceeding on the principle that since plants of all epochs of the earth's history have been constructed on the same p;eneral plan, so the same associations of colour, and of colour and form, must have i)revailed also, we may finally glance at a few conclusions to be derived from this source. During the earlier geological periods, when Acrogenous Cryptogamia (Ferns, &c.) were abundant, the secondary and tertiary colours, as green, purple, russet, and citrine, probably prevailed. During the reign of Gymnosperms, when Cycadea3 and Coniferae were numerous, the secondary and tertiary colours must still have given a sombre aspect to the vegetable world. From the commencement of the chalk formation tliere appears to have been a very marked and progressive in- crease of Angiospermous dicotyledons, which form the largest proportion of existing vegetation. Among them we find the floral organs with greater prominence in size, form, and colour; ;iiid such prominence of the "nii|itl;il dress" of the plant is peculiarly a feature of species be- longing to natural families which have attained their 152 ADAPTATION OF THE COLOURS OF maximum in man's epoch, and are characteristic of it. Brouaniart, ■■•'•■ one of our hio;hest authorities in this de- partment, states that a remarkable character of the floras of the eocene, miocene, and pliocene epochs — which im- mediately preceded man's epoch — is the absence of the most numerous and most characteristic families of the GamopctalfB.f Nothing announces the existence of Com- positcB, Personatfe, Labiatfe, Solanace^e, Boraginacea3, &c. Doubtless there were lovely flowers in former periods, " born to blush unseen," at least by human beings, but we miss those which are our special favourites, and whose cultivation is one of the characteristics of civilized man. We cannot avoid thinking that there was design in all this, that the succession of created forms in the vegetable kingdom had a reference to the epoch of man ; and that just about the time when there appeared an eye to re- ceive and convey the impressions of beauty, and an intel- lect to derive satisfaction from the contemplation of such, then it was that the most highly adorned ^productions of Flora's kingdom were called into existence. SECT. n. ADAPTATION OF THE COLOURS OF PLANTS TO THE NATURAL TASTES OF MAN. Artists lay it down as a maxim that a large portion of a painting should bo of a neutral colour. Our natural tastes would not tolerate a scarlet or purple ground to a historical painting. In a skilful piece of art the more prominent figures are made to rise out of colours which attract no notice. It is the same in the beautiful canvas which is spread out before us in earth and sky. The ground colours of nature, if not all neutral, are at least * Annales des Sciences Naturellef , 1S49. t In Gaiuopetalae there u adhesion of petals ; the flowers are tubular. PLANTS TO THE NATURAL TASTES OF MAN. 153 all soft and retiring. How grateful should we be that the sky is not usually dressed in red — that the clouds are not painted crimson — that the carpet of grass on which we tread is not yellow, and that the trees are not decked with orange leaves ! The soil, in most places, is a sort of brown — the mature trunks of trees commonly take some kind of neutral hue — the true colour of the sky is a soft blue, except when coloured with gray clouds, and the foliage of vegetation is a refreshing green. It is out from the midst of these that the more regular and elegant forms, and the gayer colours of nature come fortli to arrest the attention, to excite and dazzle us, not only by their own splendour, but by comparison and con- trast. All the gayer colours of the vegetable kingdom seem to be beautiful in themselves. The eye needs no asso- ciated object to lead it to detect a loveliness in the red rose, and the blue harebell, and the yellow primrose. But there are associations of colour in art which have a pleasing effect upon the mind. In our Schools of Design pains are taken to shew what colours may be placed in juxtaposition, and what colours may be kept at a dis- tance from each other. In the construction of tapestry, and other kinds of higher needlework, in the manufac- ture of our finer texture of fabrics, and in the staining of glass for windows, strict attention is now paid to rules on this subject, prescribed by science and sanctioned by experience. We proceed to shew that in nature colours have been associated from the beginning, according to principles which have become known to man only at a comparatively late date in the history of human civili- zation and science. In order to explain this, it will be needful to begin with a fcAV elementary statements in re- gard to light and colour. 7* 154 ADAPTATION OF THE COLOURS OF According to the commonly adopted doctrine, there are three Primary Colours, Red, Yellow, and Blue. The combination of these, in certain proportions, yields White, The absence of them all is Black. These primaries, mixed too-ether, two and two, produce what are called Secondary Colours, viz.. Orange from the mixture of red and yellow. Green from the mixture of yellow and blue, and Purple from the mixture of red and blue. From the combination of the secondaries arise three Tertiary Colours : — Citrine from the mixture of orange and green, Olive from the mixture of green and j^urple, and Russet from the mix- ture of orange and purple. There are certain other phrases which it may be needful to explain in their technical sense, as used by colourists. Tint is employed to denote the gradations of colour in lightness and shade ; Shade to express the gradations in depth from white down to black ; Hue is applied to the mixtures in comj)Ound colours. Thus we talk of a light tint of red where the red approaches to white, of a dark shade of purple where the purple inclines to black, and of hues of orange from the yellowest to the reddest, of hues of green from the yellowest to the bluest, and of hues of purple from the bluest to the reddest. When the orange has more than its proper proportion of red, we call it a red orange hue ; when in green the yellow prevails, we call it a yellow green ; and when in purple the blue predominates, we call it a blue purple. This is the common doctrine taught in schools of art ; it is correct enough for the purpose which we have at present in view, and the nomenclature enables us to express, in a rough way, the infinitely varied colours in nature,* * Newton thought that there were seven simple primitive colours, red, orange, yellow green, blue, indigo, violet. Sir David Brewster has shewn that these can be reduced to three. Some scientific men seem to reckon all such classifications as in some respects PLANTS TO THE NATURAL TASTES OF MAN. 155 The languao;e of music has been applied to colours ; and colourists talk of the Melody of colours and the Harmony of colours. Colours are said to be in Melody when two contiguous tints, or shades, or hues, run insen- sibly into each other, as when red slides into pink and white, and purple deepens into dark purple or merges into red jiurple and red. Two different colours are said to be in Harmony when their association is felt to be pleasant to the eye. Two colours are said to be Complementary when they together make up the white beam. Thus green and red are complementary, as also purple and yellow, orange and blue. The eye feels a pleasure in seeing colours in melody, or meltinGf into each other. It also feels a pleasure in contemplating certain associations of different colours. In particular, the eye is pleased when comple- mentary colours are beside each other, or under the view at the same time.* Complementary colours contrast the one with the other, but arc always in harmony. It is necessary to add that white associates pleasantly with every other colour, as does also black. The accompanying diagram {Fig. 32) is constructed with the view of shewing what colours are complementary to each other. In this figure we liave the three primary colours, red, yellow, and bhie, and the three secondaries, orange, green, and purple, with the hues of the seconda- ries on either side. We have also the tertiaries, citrine, arbitrary, and speak of the solar light as coinposod of iiulctcnn inatc mmibcrs of dlffiTently colored rays. We have no opinion to offer on these points, or any other disputed point. In regard to the nature of colour. But as it Is needful to use nomenclature of some description, wc adopt the commonly received doctrine as expressing the actual facts very clearly, and with sufTiticnt correctness for tlio purjiose which we luivo in view. ♦ Divers explanations, physical and physiological, have been given ject, considers liumford's statement "as nolliin-; more tlian an iiisenlous inven- tion of fancy." (See I'aixr in Cliem. Hep. of Cavondisli Sociely, p. IS'J.) 162 ADAPTATION OF THE COLOURS OF stalks. Nay, we have observed that, if there be but a diseased spot or wart on a leaf produced by an insect, the colour of the spot will at times be complementary to that of the leaf, as may be seen in the little galls on the leaves of willows and roses. The scales of young cones are often purple, whereas the scales of the old cones, hanging on the same tree, are citrine. In Victoria regia, we may notice on the leaf (besides the beautiful mechanism by which it is supported) red purple ribs harmonizing with the prevailing yellow green, and in the expanding flower, the red purjjle calyx harmonizing with the yellow green at the edge of the sepals.* * This frequent juxtaposition of complementary colours must have a physical as well as a final cause. If it be asked what this is, we are inclined to answer this question by asking another, the answer to which may pojsibly open up the way to an answer to the first question. When a beam of light falls on a green leaf, the green is said to be reflected and the red absorbed ; but what, we ask, becomes of the red ? When the beam falls on a purple petal, the purple is said to be reflected and the yellow absorbed ; but what be- comes of the yellow? Are the red and the yellow in these cases absolutely lost? If these constituents of the beam be lost, they are the only powers in nature which are so. In this world of ours nothing which has existed at any time is lost, even as nothing abso- lutely new comes into being. It is now a received doctrine, that the heat absorbed by plants in the geological era of the coal measures is laid up in fossil deposits, and may come forth in our opoeli when the coal is Ignited. May we not suppoes, in like manner, that the red absorbed by the plant when the green is reflected by its leaves, will come forth sooner or later, in some form. In young stem, flower, or fruit ; and that the yellow absorbed by the flower when the purple is reflected, will come out in the yellow pollen, or in some other form? We have thought at times that .as tlie pure white beam, when it reaches the earth with its atmosphere, is divided into several rays, and that no one of these is lost, and as they all come forth sooner or later, we have thus a harmony of colours in nature. We have thus the brown earth, the ultimate recipient of the rays which have passed through the atmosphere, harmonizing with the blue sky, and ligneous substances become orange when ignited. Bnt we throw out this view as a mere hypothesis in the absence of a bettor, and in order, if not to guide, at least to stir up inquiry; and we beg that it may be carefully separated from the co-ordinated facts presented in the text. In whatever way wc may account for it, there is a most singular succession as well as co- existence of colours in the vegetable kingdom. Harmonious colours come out not only contemporaneously, but consecutively. In several species of Geum, (as G. urbanum and G. intermedium,) the pet.als are yellow and the pistils purple, but it is not till the yellow petals are falling off' that the purple pistils appear. We have the same curious pheno- menon in some species of Fragraria. In Cytisus Canariensis, the yellow corolla is fol- lowed by the purple pod. In some Cactaces, the yellow flower is succeeded by a purple fruit. In Taxodium sempervirens, the young shoots are yellow green, those of a year old are red purple, and those older still, citrine. Generally branches, when young, are green, as they advance they are purple, at a farther stage they are citrine, and finally PLANTS TO THE NATURAL TASTES OF MAN. 163 These harmonies are found in plants belonging to all the principal divisions of the vegetable kingdom. Thus, among the femily of Mosses, the red or red purple teeth of the peristome are associated with the green or yellow- green capsule ; and the same is true of the different parts of their stems and leaves. Among Fungi, we have Bo- letus luridus and Boletus luteus with yellow and purple stems. In Lycopodiums, the most common colours are yellow and purple. Among Ferns, we have noticed Doodia aspera with its young fronds red jjurple and yellow green, and Dicksonia adiantoides ^\^tl^ yellow green fronds and red purple stalks. Most exotic Or- chide^ have yellow with purple spots, or yellowish green with red purple spots on calyx and corolla. In the flower of grasses, the prevailing colours are purple and citrine, russet and dark green. We have already detected this harmony among rushes, among herbaceous plants, among the cone-bearers, and trees generally. It is a most interesting occupation to trace it at every season of the revolving year. In spring it is very obvi- ous in the contrast between the yellow green leaf and the red purple of the stalk on which it grows ; thus the young leaves of the primrose are yellow green, while the stalks are red purple. At the same season we may no- tice that the flower of Tussilago is yellow, while the involucre and scales of the stalks are purple. In the summer season the powerful beams of the sun bring forth this harmony in plants of every description. In russet. Surely these successions are Instructive. We have felt a deep interest in no- ticing how, In a vast number of plants, the colours wliich make up the full heaiii do some time or other, separately or in combination, make their appearance during the life or at the death of the plant. Tlicre are also curious cases, in whicli one colour appears In the outside, and its coinploinent In the inside of the fruit. The inside of u nearly ripe fl;; Is red-purple, the outside yellow-ereen : the same is true of the pericarp In some speeles of Pojony. The skin of the berry of Mahonlas is blue, whereas tho Interior i.i orange. 164 ADAPTATION OF THE COLOUES OF autumn it is very strikingly exliibited in the contrast "between the leafage and the berry, and other fruits. Nay, it is often very visible in the fruit itself Thus in cer- tain varieties of apple, hues of red and purple are asso- ciated with hues of green and yellow green, while in some varieties of pear, yellow green, red purple, and citrine occur together. The year dies (like the day) in glory amidst a magnificence of colouring in its phase, in which prevailing hues are greenish yellow and deep red purple, and citrine relieved by dark purple spots. In winter itself, we may see the harmony in those plants which (like friends in adversity) choose that season to shew their beauty ; thus the greenish yellow corolla of the ar- butus harmonizes, very beautifully with the red purple of the anthers, and also of the flower-stalks. The eye is refreshed in the depth of winter by seeing the red berries peeping forth from the midst of the green foliage of the yew and holly. Thus does the harmony run on till the returning sun of sjiring calls forth a new cycle. We may discover in it, if we patiently seek for it, in every description of natural scene. In the grass of the fields we may observe it in the stems, which are often red purple in harmony with the yellow green leafage, and in the purple and citrine of the flowers. Nor can any one walk far in the fields without meeting plants which he has only to examine to discover that they illustrate this conjunction. If the bird's-foot (Lotus corniculatus) catch his eye, he may notice that its lively yellow co- rolla is relieved by purple on the outside of its large lobe. Or if he pick up the flower of purple clover, he will find that the anthers are yellow. If he carefully examine the common buttercups, he will find that as a set-off to the yellow flower there is purple on the calyx or some other organ. The yellow flower of silverweed (PotentiUa anse- PLANTS TO THE NATURAL TASTES OF MAN. 165 rina) has a visible contrast in the purple stalks and run- ners. He may notice how the yellow flower of common hawksbit (Hieracium Pilosella) has purplish tips and purple on the outside, and how numberless yellow syn- genesious plants, such as dandelion and Apargia autum- nalis, grow on purple stalks, and have purple spots on the involucre. Here and there he will discover Sym- phytum tuberosum, with dull yellow corolla and dull purple stem ; or self-heal, (Prunella vulgaris,) presenting its calvx with russet border and dark screen centre, sur- mounted by blue purple corolla and whitish anthers. Pos- sibly he may be so fortunate as to fall in with a rock rose, (Helianthemum vulgare,) with its yellow petals melodiz- ing into crimson, and striped with purple. In our drier meads he cannot but notice yellow rattle, (Khinanthus Crista-gaUi,) with yellow corolla tipped with purple, and Lathyrus pratensis, with purple veins in the large lobe of its yellow corolla ; and in our watery marshes the lousewort, (Pedicularis palustris.) with its purple petals and yellow anthers. In our pools he may meet with the Comarum palustre, with its dark red purple corolla and its yellow green heart. If he wander by our rivulets he may fall in with Geum rivale, with its purple j)etals, and its abun- dant and prominent yellow anthers, with its russet calyx, harmonizing with its dark green leaf If he go forth into our wastes, he will meet with our sedges and rushes with their purple and citrine. In shady and moist places he may see the common loose-strife, (Lysimachia ncmorum,) with yellow corolla, and stems and leaves tinged with purple. In our hedges he has the yellcnv gi'een leaf of the thorn harmonizing with its red ])ur|)le shoots, and growing up in the midst of tlicm the ])uri)lo vetch, (Vicia sepium,) with its purple corolla and yellow anthers ; while in the ditch there may be the lovely 166 ADAPTATION OF THE COLOUKS OF "forget-me-not," with its reddish blue and yellow orange. If he enter the wood he may see the com- mon anemone, with its purple flowers and yellow anthers, or the leafage of the bush contrasted with its berries, or the cones of the fir and pine contrasted with one another, or with the foliage. If he betake himself to the sea-side, he will fall in with the sea sandwort, (Arenaria marina,) or the common sea-jjink, (Statico Armeria,) both with purple corolla and prominent yellow anthers ; or the common sea-radish, (Eax-)hanus mariti- mus,) whose open yellow corolla harmonizes with the unexpanded flower-buds, which are purple.* We are inclined to think, farther, that there is often a beautiful harmony in the way in which different plants are associated in nature. It is a curious circumstance that the colours of some sea-weeds are red of various hues, and of others are green of various hues, and as these grow together they help to eml)ellish one another. We have heard skilful colourists declare that there is a har- mony in the colours of the plants growing together in our finest meads, and our own eye testifies to the same effect. We are quite aware that in our cultivated fields there are often plants growing together with colours that are discor- dant. We could never discover any beauty in the yellow mustard growing among the green stalks of the farmer's grain. But in nature's own meads, in all places in which she not only grows but is allowed to sow her own plants, she commonly distributes her colours very gracefully. We are not prepared to give the full rationale of this. So far as the herbage is concerned, it may be partly ac- counted for by the circumstance that yellow and purple are the most common associations in the flower of grasses, * We would refer to the Appendix for additional examples of harmonious colours in different plants. , PLANTS TO THE NATURAL TASTES OF MAN. 167 and red i^iirplc and yellow green in the stalks and leaf- age. The green foliage, too, is everywhere relieved by red fruit and red flowers, such as wild roses, ragged robins, red campions, and geraniums. In the summer and early part of autumn, there will be buttercups still lin- gering, and bird's-foot, and divers syngenesious plants, such as ragweed and hawksbit, all yellow or yellow inclin- ing to orange, and in contrast there will be purple clover and scabiouses, and self-heal, and harebell, and common bugle, and thistle, and knapweed, all purple or purple inclining to blue. We may notice, indeed, that in many of our fields some of these colours prevail to an unpleasant extent above the others. Thus in some spots there may be a disagreeable glare of yellow caused by ragwort and buttercup ; but we have noticed that if the progress of agricultural improvement does not interfere with the natural jjrocess, the thistles and knapweeds will soon so sjoread themselves as to restore the proper balance of colour. Nor let it be forfrotten that nature lio'htens the whole scene, and heightens the effect of every other colour by her white flowers, by her daisies, her stitch - worts, her chickweeds, her great white ox-eyes, her mil- foils, and her meadowsweets. One reason why man loves and longs in these times to retreat from our best culti- vated regions to the wilds of nature, is to be found in the circumstance that nature, in her own domains, min- gles so gracefully her forms and colours. We have thus a frequent harmony in the colouring of the individual plant, and a not unfrcquent harmony in the colouring of plants growing contiguous to each otlier. When the plant is near, the eye will naturally fix itself on the complementary colours of the individual ])lant, and when we are looking at a lawn at some little distance, the eye will rather select the liarmony ])reseuted l)y dif- 168 ADAPTATION OF THE COLOUKS OF ferent plants. And here it is worthy of being mentioned, that colourists acknowledge that if there be comijlemen- tary colours among objects before the eye, it will instinc- tively fix on them, to the neglect of adjacent colours. Chevreul, who is the highest authority on the subject of simultaneous contrast of colours, recommends that in planting out flowers in gardens, attention be paid to the rules of complementary colours, " The principal rule to be observed in the arrangement of flowers, is to i)lace the blue next the orange, and the violet next the yellow, while red and pink flowers are never seen to greater ad- vantage than when surrounded by verdure and by white flowers ; the latter may also be advantageously dispersed among groups formed of blue and orange, and of violet and yellow flowers," * But this eminent chemist does not seem to have observed that plants in nature are arranged on these very principles. A skilful colourist, conducted into a garden, planted out on the plan recommended by Chevreul, would at once discover that there were plan and purpose in the distribution of the plants. But there are no less convincing proofs of design in the way in which colours are arranged on individual plants, and in which plants are distributed over our meadows and mountains. Though it does not fall within our immediate subject, we may here be allowed, as an illustration of the general subject, to remark that traces of harmony of colours may likewise be found in the plumage of birds. The following seem to be the most common forms in which it presents itself. First, We often observe some dark colour, at times a black, but more commonly a dark blue, ' * See Paper by Chevreul, p. 20S, in Chemical Reports and Memoirs, 1848, of Works of CavendLsh Society. The same views are more fully developed in Chcvreul's great work, " Dc la loi dii Contraste Bimultane des Couleurs, (1839.)" PLANTS TO THE NATURAL TASTES OF MAN. 169 or very blue purple, in harmony with white. Sometimes the white is on the bellv or breast, while the dark hue is on the back ; at other times there are white spots relieving the dark shade all over the body. This is a common association in our birds of plainer plumage. It may be seen in many wcb-footed fowls, such as geese, divers, and gulls. The second most common harmony — if, indeed, it be the second and not the first — is between a sort of tawny hue, being a yellow, with more or less of red, and a dark blue, or rather dark blue purple. This collocation of colours is very frequent among rai)torial birds, as, for example, many falcons and owls, and is found among wading birds and many species of thrushes. Thirdly, in our more ornamented birds we discover red associated with green. This congruity appears, and at once arrests the eye, in a great many parrots, in a num- ber of todies, and in the Curucuis, a tribe of birds which live in low damp woods in the tropical parts of America and Asia, and feed on insects and berries. These seem to be the more marked associations, but these three forms run into each other. Thus, some horn- bills are dark blue and reddish yellow, but others have white instead of yellow. Tliis is also the case with some of the raptorial birds. In the plumage of some fowls the reddish yellow seems to be a pure orange ; this seems to be the case with some toucans — other toucans seem more nearly green and red. The same may be said of many solitary warblers, fly-catchers, and starlings. In some birds the red yellow is brightened into a scarlet, harmonizing with a greenish blue ; this is a very com- mon association amono; chatterers and finches. Tlie scarlet ibis has the greater part of its plumage of tlie hue which its name denotes, but has a greenish blue on its wings. Among pheasants wo often discover a ivd 170 ADAPTATION OF THE COLOUKS OF orange and a blue green, and tlie same colours, differently distributed, ajjpear on our more ornamented ducks. In reviewing these associations we may notice that we have, on the one side, wliite rising into yellow orange and red, and on the other side blue sliding into purple or green. We have not paid sj)ecial attention to the subject, but similar harmonies prevail, we doubt not, in other depart- ments of nature, as, for example, among insects. Any one may notice the yellow and purple on bees and wasps. The most cursory glance is sufficient to shew that many shells of mollusca are characterized by a yellow ground adorned with jmriDle spots. In another department of nature it has been remarked by Field that the brown earth harmonizes agreeably with the blue sky. Surrounded as we are by such harmonies, we are convinced that whenever the mind seeks for them it will discover them ; nay, the eye fixes on them when it is not designedly seeking for them, and rejoices in them when it can give no account of the cause of its joy. At the same time, the contemplative intellect experiences a far- ther pleasure, and a pleasure of its own, when it can scientifically explain to itself the source of all this enjoy- ment, and systematically look out for the pleasing asso- ciations of nature. The heart, rightly tuned to the praise of its Maker, will experience a farther j)leasure. Present to a skilful colourist an article of human workmanship, constructed according to the rules of simultaneous contrast in colour- ing, and he will at once say, Here are art and design. Place before him a piece of Gobelin tapestry, one of our finer carpets, or the stained glass of a window, and he will perceive at a glance that the associations of colour are not accidental, but that they are purposely suited to the physiological and psychical nature in man. We are PLANTS TO THE NATURAL TASTES OF MAN. 171 convinced that there are equally clear proofs of con- trivance in the colouring of natural objects, organic and inorganic. Indeed, colourists, long ago, observed that there was a beautiful harmony in the colours of nature ; and within the last age, Field and Hay, and very pos- sibly others, have stated what is the nature of this har- mony, though they have not followed it into the various departments of natural history. He who can trace up all these adaptations to Him who causes His works to make sweet music by their harmony, has surely here a source of higher — we should rather say, of highest joy. But the question is here started. Are there no colours associated in nature except harmonious ones ? This is a question which we are not prepared dogmatically to answer, either in the negative or positive. One thing, however, seems to us very certain, that complementary colours appear so often in nature, and cast up, under such different modifications, and in such a variety of objects and situations, that their conjunction cannot be the result of mere chance. Besides the generalized flicts of a positive character, we are prepared to say negatively that we have never observed in a corolla, or in any one organ of a plant, pure red and pure yellow, or blue and red, in contact with each other.* But in making these affirmations we are, at the same time, prepared to admit that there are colours in nature in juxtaposition which are not comi:»lementary. This, however, just raises the question. Can no colours be pleasantly associated except complementary colours ? This question must be answered in the negative, and being so answered, a host of inquiries * The same statement was made to us by Mr. Wood, an experienced flower painter, and lately assistant master In the Belfast School of Design. Ho farther Informed us that he Invariably found assoeiatlons of harmonious colours In the dlfTcrent parts of plant", such as wo have been describing'. 172 ADAPTATION OF THE COLOURS OF come to be made cas to what other associations are agreeable, and these should be followed by a series of investio-atious, having it for their end to discover how far all the non-complementary associations of nature can be described as pleasant. Chevreul tells us that we cannot prescribe arrangements of non-complementary colours, so as to please the eye, in as positive a manner as may be done with reference to the assortment of complementary colours. " This is the reason," he adds, " that in treat- ing of the distribution of flowers in gardens I have only recommended an assortment of flowers whose colours are complementary, at the same time that I admit the exist- ence of many other assortments productive of a very agreeable effect."* This whole subject is just opening upon us, and we must be satisfied for the present to sub- stantiate a certain amount of truth, to acknowledge that there are unsolved points and difiiculties, and trust that these may be cleared up by further investigation. We must here state, however, that many of the seem- ing exceptions to these general views, are exceptions merely in appearance. It not unfrequently happens, in the vegetable kingdom, that the discord between two contiguous colours is sub- dued by a patch of white, which, like innocence, (of which it has always been reckoned an emblem,) has never occasion to be ashamed of itself, for it may appear any- where, and is in harmony with every object it can meet with. In Lycopsis arvensis, in harebell, and speedwells, the blue of the petals has no complementary orange, but then it is beautifully relieved by an adjacent white. It may seem as if the leaves of plants were liable to be seen simultaneously with every other colour in the vege- * See in works of Cavendish Society, Chemical Reports and Memoirs, 1848.— Paper by Chevreul, p. 219. PLANTS TO THE NATURAL TASTES OF MAN, 173 table kingdom, that there must be discord when the green leaf is perceived at the same time with the yellow and blue of the flower, Chevreul, in speaking of the artifi- cial arrangement of flowers in a garden, lays down a rule which enables us to escape the difficulty. " I must, how- ever, reply to the objection that might be made, that the green of the leaves, which serves, as it were, for a ground for the flowers, destroys the effect of the contrast of the latter. Such, however, is not the case ; and to prove this, it is only necessary to fix on a screen of green silk two kinds of flowers, (in the manner pointed out in the paper,) and to look at them at a distance of ten paces. This admits of a very simple exijlanation, for as soon as the eye distinctly and simultaneously sees two colours, the attention is so riveted that contiguous objects, espe- cially when on a receding plane, and where they are of a sombre colour, and present themselves in a confused manner to the sight, produce but a veiy feeble impres- sion."* Nor is it to be forgotten, that the coloured flowers of many plants are raised out from the midst of their leaves, and are so far above them that the petal and leaf do not come simultaneously into view in a marked manner. This is the case very obviously with harebell, dandelion, hyacinths, and many other plants. In such cases, it may be found either that the flower has a beauty of its own independent of any adjunct, or that it has a harmo- nizing concomitant in some other plant usually growing in the neighbourhood. More important than any of these, we liud that there is a physiological provision in the eye itself, which helps it to overcome any sliglit defects in the balancings of the colours in nature. Chevrcul lays down the law, that in ♦ Chcvreul's Taper on Chemical Reports, p. 20T. 174 ADAPTATION OF THE COLOUES OF PLANTS, ETC. the case of tlie eye seeing at any time two colom's which are in contact, they will appear as dissimilar as possible. In other words, on two colours heiug seen simultaneously, the complementary of the one will be added to the other. Thus, if a yellowish green leaf and a red flower be under the view at the same time, the yellow green will thereby be more inclined to green, and the red will acquire a slight tinge of blue, and the two will be brought more nearly into the complementary state. In this way the eye itself can rectify any slight defect in the harmonies of adjacent colours. CHAPTER lY. THE VERTEBRATE SKELETON. SECT. I. — THE HOMOLOGIES AND H0M0TYPE8 OF THE VERTEBRATE SKELETON. In the last age there raged a famous scientific contro- versy, which may be summarily represented as a dispute us to which of the two great principles whicli we are un- folding should be detected in the animal frame. The illus- trious Cuvier, in building up the science of comparative anatomy, proceeded, in all his investigations, on the prin- ciple that every particular member of the body had a special or final cause. On the other hand, the great Geoffrey St. Hilaire, first the co-operator and then the rival of Cuvier, delighted to trace a unity of plan running through the bones of the skeleton. In 1830, this con- troversy came to a pubUc explosion, which was viewed with intense anxiety by all interested in natural science, and in particular by the poet Goethe, who proclaimed it to be a far more important event than the French Revo- lution, which was ringing that same year in the cars of Europe. In conducting the dispute, extreme positions were taken by both sides. Attaclied to tlie ])rinci])l(^ of final cause, and having found how prolific it was, in liis hands, of brilliant discoveries, Cuvier was not willing to admit the thcor}^, (though he helped greatly to establish the fact,) that there is in the skeleton a general corre- 176 THE HOMOLOGIES AND HOMOTYPES spondence of parts, wliicli can have no reference to the wellbeing of the animal, or the special functions of the or'^an. Geoffrey St. Hilaire, on the other hand, did not see that his doctrine of analogy was perfectly consistent with teleology, and he connected his theory of unity with the untenable doctrine of the transformation of species. This dispute should now he regarded as settled, by the establishment of both doctrines — both that of general homology and that of special teleology ; and the former, we are convinced, will be found, when properly interpre- ted, to yield as rich a contribution to the cause of natural theology as the latter. Any one may convince himself, very easily, that in a general sense there are model forms in the construction of the skeleton. He will see at a glance that every spe- cies of animal has its normal shape, and this is, to a considerable extent, determined by the length, thickness, and relative position of its bones. In the human frame, there are organs which have been used as standards of measurements, which they could not have been unless their size had been approximately definite. The length of the arm, from the elbow to the tip of the mid-finger, furnished the cubit to many nations of antiquity. The hand-breadth and the span were measures among the ancient Hebrews. In not a few countries the stretch of the arms, the pace, the palm, the breadth of the thumb, have been used to indicate linear measure. Among artists the human frame has long been known to have proportions in its members. The visible outline of the head in front is divided into four equal parts ; — the first, from the top of the head to the setting of the hair ; the second, from this to the root of the nose ; the third, the nose ; and the fourth, from the lower part of the nose to the chin. The height of the figure is found to be eight OF THE VERTEBRATE SKELETON. 177 heads ; the first reaching from summit of head to chin, the second from chin to breast, the tliird from breast to navel, the fourth from navel to top of thigh, the fifth to middle of thigh, the sixth to knee, the seventh to the calf of the leg, and the last to the heel. The body is thus divided into two equal parts — one from head to hip, the other from hip to lieel. The length of the frame is also known to be equal to the line drawn from finger-tops to finger-tops of the outstretched arms. But without dwelling longer on these general topics, we proceed to shew, in a scientific manner, that the ver- tebrate skeleton consists of a series of pieces constructed on a common plan ; and in doing so, we shall largely avail ourselves of the masterly researches of Professor Owen, who has done so much towards the comj)letion of this most interesting subject. We know that the skeleton is not a peculiarly inter- esting object to an untutored eye. It has been associated, in the minds of many, with the grave's mouth and mor- tality. It possesses in itself no physical beauty ; it is meant to be wrapt up from the view by a covering of flesh and muscles, which are made, for our gratification, to present themselves in full and rounded forms. Still, to minds which are fitted to penetrate beneath the sur- face, it has become an object of intense interest, and is felt to possess not a little beaiity. The reason is, that there has been a perception of the unity of the structure along its whole length, and from the highest to the low- est animal in the class, and of the suitableness of the infinitely varied parts to their infinitely diversified func- tions. Each of the series of parts which makes up tlic verte- brate skeleton is called a Vertebra. It will be sufficient for our purpose to indicate here the principal parts of the 8* 178 THE HOMOLOGIES AND HOMOTYPES ns typical vertebra, without entering into those more minute details which are necessary for the purposes of the com- parative anatomist ; for these details vfQ would refer to Professor Owen's paper on the Megatherium, in the Phi- losophical Transactions for 1850. Typical Vertebra consists of a centre or body, around which are arranged other pieces, (called technically apophyses, or projecting parts,) so as to form two principal arches, one supe- rior,* the other inferior. The upper arch gives protection to nervous matter, and is hence called neural : it is bounded on each side by two principal pieces, called neurapophyses, and is closed above by the neural spine, so called from its frequently pointed form ; (it is, however, The lower arch, called haamal, pro- tects blood-vessels, &c., (hence its name, from Greek, haima, blood ;) it also consists of lateral pieces, called respectively pleurapophyses and hc'emapophyses, and is closed by the heemal spine, which, like the neural spine, is sometimes cleft. The body of the vertebra may be con- sidered the foundation of the arches, and the neural and hasmal spines represent, in position, the keystones of each. Sometimes the upper arch comprehends a pair of bones, called diapophyses, and the lower an additional pair, call- ed parapophyses. lis PlO. 33.t sometimes bifid.) * In the erect position of man, these are respectively posterior and anterior. + Fro. 88. Typical Vertebra; «■«, nenral spine; w, ncurapophysis ; N, neural arch; c, centrum, or centre piece; pi, pleurapophysis ; h, hsemapophysis ; /w, haemal spine ; II. bsemal arch; d, diapophysis; p, parapophyeis. OF THE VERTEBRATE SKELETON. 179 7lxi Generally sjieaking, it is not difficult to demonstrate, that in the chain of bones extending from the head to the tail inclusive, we have a series of pieces partaking of the nature of the common typical structure just described. It is true that some present a near approach to the model, while in others the real nature of the parts is consid- erably masked, so that careful ex- amination is necessary to show the relation. Knowing the type, how- ever, we can explain all departures lA from it, whether owing to omission or contraction, adhesion or compli- cation of pieces. As there is a model vertebra, so there is an archetype skeleton, and we shall transfer to our pages the instructive dia- gram given by Professor Owen in his work on the " Homologies of the Vertebrate Skeleton." The elements of each vertebra are indicated by the peculiar shading, — n, neurapophyscs, . thus ///^ d, diapophyses, . . thus p^ parapophyses, . , thus c, centre or body, . . thus pi, pleurapophyses, . thus \Xs\ ws, neural spine, and A.s', hjtimal spine, are left uusliaded, the a})pendages are represented by dots. • Vie. M. Tho relations of tho parts In Fig. 88 will be rendered raoro evident by com- paring It with Fig. 84; tbo references arc the same In both; y, hypapophysls ; e, cpapo- physls. 1/ : S , -. , «> t4 << 5 -«:'5 "3 "3 5 "3 en > y* «3 "S ^ ^ 13 a J3 01 1 "i 0) (D _>. (U > O "« 3 0) a •0 •3 o. ■3 s Ot 1^ 3 ja t- K "rt VI a d rH pj" -p o o 2 o. 3 1 O a 1 a M CS a) c/l 3 a 3 a 3 60 a "3 p, §1 a a 00 % tH 0! 3 T3 « a C P. cT 0. CO 6 1^ OS '3 3 "5 t/i 1s. to cn £ .2" CO tn id" 0) 3 a 5 tn o "5 ^* *o c OJ J3 ol 3 eft ■3 at u 3 5 2 .a "5 0. 1— ' g =2 s 0, xs V- "o a g 3 '0 ■*-» cT T-H .0 B s T-l ^' >% (I) 1 5 c _B P. CO 1 tM (m S 3 a a > "0 "3 9 5 a 3 ■a a & Li L. a 1 P< 3 o B ■a ■a g 5 •;^ i' ,a si 01 J3 3 tn ^ fd <2 ;::; 'a . f-< *« be c c3 .2 tn" •a 3 3 C3 a '5 m Q •a ■3 a ■y t- a 05 -C c a -M od 3 ^ 0) 4^ ct 0) 1 2 c 6 c en en .2 5 r/l CO bD C3 a 0) 3 "3 S o (- rt c2 ., t-. 1 c CD c. 5^ i 0) p. C4 c: ■a ■D H 3' ■3 5 00 d « © ■3 J3 P. 'A CD" 5« c! e Si c CD '^ 13 c d" a t. h ffl Li 3 13 ci ,n '^ CS HOMOLOGIES OF THE VERTEBRATE SKELETON. 181 The four anterior vertebra) constitute the skull or brain-case ; the first is called nasal, because it supports and protects the organs of smell ; the second is named the frontal vertebra, corresponding to the forehead ; the third is the parietal, from Latin paries, a wall, because its elements chiefly form the sides of the skull ; the fourth is denominated occipital, coiTCsponding to the occiput, or hind-head. Succeeding these we observe a series of pieces forming the bony framework of the neck, chest, abdomen, loins, and tail. Generally speaking, we observe the following peculi- arities in these different regions respectively ; in the head the neural arch is higldy enlarged in order to protect the brain, in the neck and succeeding regions the same arch is only moderately developed in correspondence with the size of the spinal cord. In the trunk it is the hfemal arch which attains largest dimensions, its functions being to guard the larger blood-vessels and viscera. In the tail both arches are generally suppressed, and the body of the vertebra alone remains. It is admitted that the bony framework of man devi- ates very considerably from the archetype, but as " more than ninety per cent, of the bones in the human skeleton have their homologues (or namesakes) recognised by common consent in skeletons of all vertebrata,"* if it can be shewn that the skeleton of man consists of a series of simikir pieces, and may be refen-ed to the archetype, it will be obviously unnecessary to occupy space in discuss- ing the same points regarding animals lower in the scale , these last, however, will afford examples not a few under the special branch of our subject. Since the day when Oken saw the bleached skull of a deer in flic llartz forest, and exclaimed, " Ft is a vcrte- ♦ Owen, Lecture at Royal Institution, January IS'lT. 182 THE HOMOLOGIES AND HOMOTYPES bral column," the idea that the brain-case is really made up of vertebrge has been fully tested and matured by anatomists of the highest authority, among the most con- spicuous of whom is our own countryman, Professor Owen. There has doubtless been difference of opinion as to the number of vertebras composing the skull, but respecting its general construction there is agreement among the best authorities. First, or nasal vertebra in man.— The centrum or body is the bone called vomer ; the neur apophyses are formed by the perpendicular plate of the ethmoid bone, which, in reality, consists of two pieces united toge- ther ; the neural arch is thus obliterated ; the neural spine is bifid, and is represented by the two nasal bones. The inferior arch of this vertebra is composed as fol- lows : — the pleur apophyses are formed by the palate bones ; the hceinapophyses are the bones of the upper jaw ; the hamal spine is divided, and consists of the intermaxillary bones which support the front or incisor teeth. Second, or frontal vertebra. — The centrum is formed by the presphenoid bone ; the orbito-sphenoids are the neurapophyses ; the frontal bone forming the ex- panded brow in the human head, is the flattened neural spine ; in the inferior arch the ring of bone, called by • osteologists the external auditory process, is the pleura- pophysis; the lower jaAv represents hcemapop)hysis and hcemal spine. Third, or parietal vertebra. — The centre is formed by the basisphenoid bone ; the alisphenoids are neura- pophyses; the parietal bones form the cleft and expanded neural spine; the styloid pieces of the temporal bone are pleur apophyses ; the lesser cornua of the hyoid bone (lying in the upper and fore-part of the neck) are hcema- OF THE VERTEBRATE SKELETON. 183 popliyses; the body of the same bone forming the Jicemal spine, and thus completing the arch. Fourth, or occipital ver- tebra. — The basilar piece of anatomists is the centre ; the sides which bound the open- ing in the occipital bono, through which the upper part of the spinal cord is continu- ous Avith a portion of the cere- bral mass, constitute the iieti- rapopliyses surmounted by the expanded neural spine. The lower or haemal arch of this vertebra is removed from its natural position in man, as in most vertebrata — the reason of this will be discussed in a subsequent para- graph. The scapulas or shoulder-blades are the pleu- rapophyses ; their appendages, called coracoid processes, constitute the hcemapophyse's ; and the haemal spine is wanting."!" The seven vertebrge of the neck are admitted to pos- sess the general elements of the typical vertebra, the parts, however, are generally considerably modified in relation to the functions of that portion of the frame to which they belong. The vertebrae of the back are twelve in number ; the neural canal in each is sufficiently obvious, and of mo- derate size ; the haemal arch is highly enlarged ; the ribs ♦ Fig. 86. Parietal segment, or vertebra of man. The neural arch Is ample, (n,) to protect part of the brain : the htemal (n) is contracted. In this case the diapophysos, f/, anr wedirofl between the neurapophy-sts, », and the lari^e neural spine, ns; ^ Is a piece called f-papophysls, which lies upon the centrum, c ; a, h, and /w represent the parts of the hyoid bone Huspended in the upper and fore-part of tlio neck, ami closliij,' llio hii'iiial arch. t In order to simplify the subject, wo have omitted reference to diapophysos and pa- rapophyses. 184 THE HOMOLOGIES AND HOMOTYPES are the pleurapophyses, succeeded by the hasmapophyses, or cartilages of the ribs, and finally closed by the united haemal spines, which constitute the sternum, or breast- bone. In the five vertebree of the loins, the elements are not so obvious as in those of the back. The pleurapophyses are short, and firmly joined to the central portion ; the haemal arch is not completed by bony elements. The five sacral vertebree have their bodies firmly joined in the adult, and these same elements diminish in size from the first to the last. The neural arch is complete only in the first three ; the neural spines of the last two are absent. The heemal arch of the first sacral vertebra is usually considered as formed of that part of the pelvis called ilium ; the portion called pubis is a hsemapophysis; the ischium is the hasmapoj^hysis of the second sacral vertebra. The four or five succeeding and terminal pieces of the back-bone in man, correspond to the tail in the lower animals, and for the most part consist of the centra only. Such is a brief summaiy of the generally admitted views held respecting the nature of the human skeleton, (exclusive of the limbs, which will occupy attention in subsequent paragraphs ;) and as such have been, in many instances, arrived at by comparison with the bony frame- work of animals lower in the scale, it is unnecessary to allude to these under this department of our subject. While, therefore, the entire skeleton in every vertebrate animal is constructed according to a common plan, and the series of vertebriB of which it consists may all be re- ferred to one model, it appears to us that there is good reason for proceeding a step farther, and coming to the conclusioUj that unity of form also prevails in the indi- OF THE VERTEBRATE SKELETON. 185 vidual pieces of tlie typical vertebra and its appen- dages. We may first allude to the appendages or limbs, as affording the most evident indications of such unitv. If we take, as the typical form, a bone of the hand (meta- carpal,) or of the foot (metatarsal,) we shall find that there is a striking resemblance to it in all the elements of every limb.* This typical bone may be described as having a nearly cylindrical shaft, dilated towards its two extremities. The large cannon bone in the foot of the horse (see Fig. 43) may serve to illustrate the form alluded to. Now, this is the prevailing shape in all the principal bones of the limbs. In man, for example, such general outline exists in the bones of the arm, fore-arm, hand and fingers ; in thigh, leg, foot, and toes. The short and frequently irregular bones of the wrist and ankle present the greatest departure from the type ; but in some animals the relation is obvious enough. Thus, in the common frog, certain of the ankle-bones (calca- neum and astragalus of anatomists) assume exactly the typical f jrm. In the individual pieces of the vertebra itself, we shall find evident traces of similarity to a typical form. The centrum, or body of the vertebra, presents a close approach to the model in the caudal part of the skeleton. This is evident in a great number of instances. One may suffice: the bones of the tail, in the young African elephant, con- sist of centrum only, and each very much resembles in form a metacarpal or metatarsal bone. • It Is a fact worthy of notice here, that the same form of an organ appears in plants. For example, tho sialic which supports the leaflots of species of ^scuhis, the horsc- cbehtnnt, exactly resembles a bone of the hand or foot; and In the inanna-ash, we have four or more pieces of like shape fomiint; the main stalk of tlie eompniiiid leaf, separatln-f at tho joints, and resembling a series of phalanges, as In a linger or toe. Tho same gen- eral outline Is often visible In the bolo of well-developed ti-ocs. 186 THE HOMOLOGIES AND HOMOTYPES The elements of tlio inferior or htemal arcli present very clear exam23les of conformity to the type. Pleura- jjophyses or ribs are not always curved and fiat bones, such as we see in Mammalia generally, and in the New Zealand bird called AjDteryx. In not a few instances, especially certain aquatic birds, (the guillemot, for ex- ample,) the ribs are narrow and cylindrical, and bear considerable resemblance to the lengthened bones of the fingers which form the framework of the bat's wing. The numerous ribs of the boa and other serpents, differ from the model only in being curved. The shoulder or sca- pular is a pleur apophysis, (sometimes with conjoined hsemapophysis.) In man and mammalia generally it is broad and flat, but in many birds it is long and narrow, exactly like a rib ; and since, in some aquatic birds, the ordinary ribs very much resemble the model shape, we have thus transitional forms conducting us to the original type. The pelvis, intended to support and protect im- portant viscera, and give attachment to powerful muscles, shews also striking departure from the model. But in the frog, the iliac bones (pleurapophyses) very much re- semble the typical form. We have evident examples of likeness to our assumed model in the other elements of the lower arch, viz., the rib and its cartilage, (pleurapo- physis and hasmapophysis.) Mere curvature of the parts, so as to assist in the formation of an arch, cannot be considered as very materially affecting the conclusion to be drawn. As regards the ha3mal spine, it would not be easy to recognize any conformity to a primary shape in the sternum or breast-bone of man or of a bird ; but in many animals, such as the lion, elephant, walrus, greyhound, &c., this part of the skeleton consists of a linear series of pieces, exactly resembling the typical form. OF THE VERTEBRATE SKELETON. 187 In the elements of the superior or neural arch, the departure from the model is generally greater and more constant than it is in the lower or haemal arch. The flat hones of the skull deviate widely from the type, but not more so than the shoulder blade or the pelvis, both of which, as we have seen, present transitional forms. The very important functions of the brain-case, as a protector of the important parts within, necessarily imply a great and constant deviation from the model form. If we exa- mine the principal element of the neural arch (neurapo- physis) of any large vertebra, as in the baleen-whale, or in the finner, we see that, after aU, it may be referred to the same general form which ribs assume, and they, as we have seen, can be traced to a model bone. The neural spine is indirectly referable to the same type, and by similar steps. We observe it in the dorsal region of ruminants, and other animals attaining great length, and resembling a rib, being, however, straight. There is but little difference in form between the longer neural spines of the dorsal vertebrje in the horse, and the first rib of the same animal. On the whole, we think there are evident traces of community of form in the parts of the typical vertebra. The subject is interesting, and merits attention and fur- ther investigation by those favourably situated for oppor- tunity of examining and studying the forms and transi- tions in an extensive series of skeletons. There are not only proofs of general order as regards reference to a typical bone, vertebra, and archetype skeleton, but there are some well-established facts respecting the number of the vertebrsB themselves. Those entering into the formation of tlie l)raiii-case in mammalia are four, those of the neck are seven, except in tlie case of the three-toed slotli, which has 188 THE HOMOLOGIES AND HOMOTTPES nine, and the manati, in whicli only six are said to exist.* The dorsal vertehree are usually considered as charac- terized by the presence of long, arched, more or less moveable, pleurapophyses or ribs, and, taking such as a mark of distinction, we find that their number varies in different cases. In most carnivorous or flesh-eating animals, the num- ber of vertebra of back and loins together is very con- stant, though the exact number of those called dorsal presents variations, as the following examples will shew : f — Back. Loins. Total. American Black Bear, 14 6 20 Dog, 13 7 20 Panther, . . . , 13 1 20 Spotted Hyjena, 15 5 20 Glutton, .... 15 5 20 According to Professor Owen, all mammiferous ani- mals, called Artiodactyles, as the ox, &c., having either two or four toes, agree in having nineteen vertebrae be- tween the neck and the sacrum ; this is remarkable when compared with the odd-toed group, usually called Peris- sodactyles, which present great irregularity in the number of the corresponding vertebrte, there being, for example, twenty-two in Ehinoceros ; twenty-three in Tapir and the Palaeotherium ; and twenty-nine in Hyrax. DIVERGING APPENDAGES OR LIMBS. These constitute the limbs of animals, which are just lateral appendages of the typical vertebra. The simplest * According to Maclise, some of the monkey tribe have only five or six neck vertebrae, and occasionally also in man tlie same occurs. — (Medical Times and Gazette, January, 1854.) + Cooto on Homologies of Human Skeleton, p. 26. OF THE VERTEBEATE SKELETON. 189 example of such appendage is very evident on examining the skeleton of a bird. Attached to its ribs or pleurapo- physes, there are seen short flat pieces, which, being- directed backwards, ovcrlaj) the external surface of the next rib behind. (See a. Fig. 37 ; also a and 65, Fig. 35.) Similar appendages are found, less perfectly de- veloped, in certain reptiles. They also occur in the abdominal parts of the most bony fishes, in which their length is such that they reach even to the skin. They are considered as parts of the primitive segment or ver- tebra, though less constant than the arches which support them. Now, the simplest form of limb is, in its nature, but very little removed from such diverging appendage ; in some of the lower vertebrata, as Protopterus, the limbs are reduced to an unbranched ray. Through various a species of Ampliiuma, and in Proteus, we observe greater com- plexity, (though still of low tyi)e compared with the extremities of man,) and this goes on step by step in dif- ^'°- ^^•* ferent animals, till we reach the arrangements which characterize the higher forms. The Protopterus, whose simple limbs afford proof of their identity with the diverging appendages of the typical vertebra, present also proofs that the fore and hind limbs are homo- ty])es, both being in that animal precisely of the same simple nature. But even in the higher animals, man * Fi'!. 37. Occipital vortcbra of Protopterus. Tho haemal nrch is lar^f, consl.Htlng of pi. plourapopliysli; h. hnjinnpophysis; hii'inal spino is wanting,'. Tho long, simplo, Jointed ray, a, &7, is tlio diverging appendage or nidlinontary limb. 190 THE HOMOLOGIES AND HOMOTYPES for example, the resemblance is siifHciently obvious ; the arm and thigh, fore-arm and leg, wrist and ankle- joint, hand and foot, are the corresponding parts of each limb ; these members are therefore homotypes. But under whatever forms the limbs exist, they are sup- ported by inverted arches, the presence of which is more constant than that of the appendages which they support, and for an obvious reason — the arch is required to pro- tect certain important organs which are always present, as the brain and spinal cord, heart and lungs ; the ap- pendage of the arch comes in as a secondary instrument, necessary, doubtless, in the economy of the animal ; but yet less important in a general sense than the other or- gans just mentioned. The parts usually considered as entering into the forrh- ation of the upper and lower limbs in man, are the following : — The scapula, or shoulder-blade, and the attached process called coracoid, represent respectively pleurapophysis and ha3mapophysis of the occipital verte- bra ; the clavicles, or collar-bones, are the hsemapophyses of the atlas, or first vertebra of the neck ; there is here, therefore transference of arches (which are also imper- fect) from their natural position ; — the end of this we shall afterwards examine. Tlien follows the arm-bone, next the two bones of the fore-arm, called radius and ulna ; then the carpus, or wrist, composed of eight bones apparently, but really of ten in two rows ; connected to certain of these, we observe five bones of the hand called metacarpus, then follow those of the fingers, styled pha- langes, each digit having three, excepting the thumb which has two. The pelvic portion of the skeleton has been already noticed ; it is in like manner an arch supporting diverg- ing appendages, the lower limbs. Each of these consists, OF THE VERTEBllATE SKELETON. 191 first, of tliigh-bone, succeeded "by tlie leg-bones, called tibia and fibula ; then follows those of the ankle, the tar- sus of anatomists, consisting apparently of seven bones in two rows, which, however, really represent ten primi- tively distinct pieces. Then follow five metatarsals, or bones of the foot, and connected with their lower ends are the toes, each, with the exception of the great toe having three bones. Now, whatever be the functions of the extremities in any of the higher vertebrata, we find all, whether fore or liind limbs, constructed on the same plan as that just described, five being the typical number of digits. It may be remarked how dificrent is the relative develop- ment of the digits, of thumb, index, middle, ring, and little fingers, styled, respectively, 1st, 2d, 3d, 4th, and 5th in the human hand.-'-" The first digit has only two joints ; the fifth has the usual number, viz., three, but the whole being short ; the second comes next in length, then the fourth ; and the third is the most highly deve- loped of all. These peculiarities have distinct reference to the general permanence of these digits respectively, and throw light on certain modifications observed in ani- mals lower in the scale. In the typical limb, the shortening of the thumb and little finger, or the first and fifth digits, is a step towards their disappearance,! the 2d, 3d, and 4th being more permanent ; the two last reaching the ground in the ox, and the longest of the two, namely, the 3d, is the only one which serves as a point of support in the horse. Professor Owen remarks, that "a perfect and beautii\il • The «aiiic numbers are used to represent the toes; great toe, number 1 ; little too number 5. t A «linller law reigns In certain plants. In Crucifoiie, (cabba?<> tribe,) tbo staiiiona are usually six, four of these belns longer than the other two. In Cardamhie hititnta there are usually only four, the two shorter being absent. 192 SPECIAL ADAPTATIONS parallelism reigns in the order in which the toes succes- sively disappear in the hind-foot with that of the fore- foot."* Commencing with man as possessing the typical num- ber, and descending to the lower animals, we find that that digit, (the first, or thumb, viz.,) whose uses, par ex- cellence, characterize him, is one of the first whicii disap- pears. Departure from the typical five is a characteristic of mammalia lower in .the scale, hence the tetra-, tri-, di-, and mono-dactyle limbs common among them.f Descend- ing lower in the scale to fishes, we find the limbs present- ing often (with a nearer approach to the simpler diverging appendages) a less subordination to the typical number, there being usually an excess. This, however, as Professor Owen remarks respecting the pectoral fin of the skate and its numerous digits, is not an example of complex devia- tion, " true complexity not being shewn in the number, but in the variety and co-ordination of the parts." In a word, all diverging appendages or limbs are constructed on a common plan ; we shall afterwards examine their numerously diversified modifications for special ends. We also observe in them evident traces of order as regards a law of number, and a general rule in accordance with which they are present or absent, as the necessities of the animal require them or not. SECT. II. — SPECIAL ADAPTATIONS IN THE STRUCTURE OF THE SKELETON. The subject here opened to us is of vast extent, and even not yet thoroughly exhausted by all that has been done in human and comparative anatomy. It must be * On Limbs, p. 23. t This has reference to digits which attain functional size. II i IX THE STRUCTURE OF THE SKELETON. 193 acknowledged that the relation between special modifi- cations or departures from the general plan, and final ends of such, have not been determined as to every part of the animal frame. Nevertheless', so many striking- examples present themselves to the careful and unpre- judiced observer, that it may be considered a legitimate conclusion that there is such a general relation, although the cautious reasoner may hesitate to give a positive decision in every instance which may come under his notice. We can indicate only some of the more obvious cases illustrative of the coincidence between the principle of order and that of special adaptation. We may appro- priately open this part of our subject by glancing at the modifications observed in the vertebrate series in man. In the cranial vertebras we observe two remarkable contrasts in the development of the neural arches ; which are more or less extended according to the purpose which they serve in reference to the particular part of the brain over which they are situated. The great size of the nervous centre, that is, the brain, requires a correspond- ino; enlarsrement in certain neural arches, and this is found to be actually provided. Each vertebra gives pro- tection to corresponding parts of the nervous matter ; thus, the cerebellum is protected by the occipital, the mesencephalon (or middle portion)* by the parietal, and the prosencephalon (fore-part of cerebral mass) by the frontal vertebra. In all of these the neural arch is ample, in distinct relation to the size of the part requir- ing defence. The less development, or rather nearly complete obliteration, of the neural arch in the first or nasal vertebra, is commensurate in man (and other ani- * Comprehending also Pons Varolii, Corpora quadrigemliia, pituitary body, and third ventricle. 194 SPECIAL ADAPTATIONS Fig. 38.* mals besides) with the small size of the remaining portion of the brain mass represented by the olfactory ganglia. It is by means of the first and second vertebrse of the neck that free rotation of the head is effected. The anterior part of the first (forming a portion of its centre) is excavated, in order to receive the tooth- like projection of the second, or axis, which is so called because there rises from the upper part of its body a piece, round which the first, or atlas, plays as on a pivot, giving rise to the lateral movements of the head. The base of this pivot is in reality the body of this second vertebra; its apex, however, is formed of part of the body of the first, removed from its natural position, and united to that of the second. Now, we do not consider it any strained inference when we affirm, that there is here presented to us a notable instance of special adaptation for a particular function. Generally speaking, the heemal arch is imperfect in the vertebras of the neck, because the large size of its ele- ments (viz., pleurapophyses, htemapophyses, and heemal * Fig. 38 represents the first neck-vertebra in man : it is called atlas, as supporting the head. A strong ligamentous band stretches across the large central opening, and divides it into two. The tooth-like projection of i''j(/- 39 is received into the fore-part of this divided ring, the posterior allows passage to the spinal cord. t Fig. 39 is the axis or second vertebra of the neck in man. The apex of the tooth- like projection is part of the centre or body of the atlas, joined to the body or centre of the axis. Fio. 39.t IN THE STRUCTUKE OF THE SKELETON. 195 spines) would have interfered with free motion in tliis region of the body. Nevertheless, certain parts which, on a cursory glance, appear to be absent, are in reality present, but are specially modified by decrease and coal- escence ; thus, the portion of a cervical vertebra project- ing outwards on each side, and hence called by anatomists the transverse process, in reality consists of diapophysis, parapophysis, and a short pleurapophysis or rib, firmly joined, but together forming a hole or short canal and a groove, to give protection and support to a blood-vessel and nerve respectively. The excessive development of the htemal arch in the dorsal vcrtebne, is a provision for the large and important organs to be protected — the heart, lungs, &c. The elastic and moveable ribs (plcura- pophyses) and their cartilages (hgemapophyses,) are ad- mirably adapted to the exhalation and inhalation of at- mospheric air during the act of breathing. The vertebras of the loins are large and strong, thus aifording a firm basis of support to the sujserincumbent column ; the haemal arch is not completed by bony ele- ments, but by soft elastic Avails, which yield to the vary- ing expansion of the viscera within. The union of the sacral vertebra gives additional strength to this portion of the column, supporting, as it does, the elastic spine above it. The excessive develop- ment of that part of the htemal arch — the pelvis of ana- tomists — is obviously intended to support and protect the larger viscera, and to present a surface of attachment for powerful muscles. The united bodies of the coccygeal series, forming a partial concave floor to the pelvis, afford additi(jnal support to the organs protected by tliis last. In short, while the skeleton of man consists throughout of a series of parts all I'ormed on one model, yet there is a wide range of difference in most of them, and the special 196 SPECIAL ADAPTATIONS modifications have in all cases a very decided, and, in most instances, a v.ery obvious relation to tlie development of different organs, without which our goodly frame could not perform its functions, or even continue to exist. We may now examine some of the special modifica- tions of vertebral elements, as exemplified by animals lower in the scale ; from a multitude of instances, our limits constrain us to select only a few. Whether we examine fishes, reptiles, birds, or mammals, we shall find obvious illustrations of departure from the model or type in accordance with some function necessary to the very existence of the animal. In Ophidia, or serpents, certain elements of the two anterior cranial vertebras are freely moveable on each other, instead of being closely joined together, as is usually the case ; strength and firmness are here sac- rificed to mobility and expansile power of the parts, and why ? The arrangement has a clear and express relation to the mode of feeding ; serpents often swallow very large prey entire ; but this they could not do were the parts firmly banded together. As it is, the mouth is capable of great extension, and the prey is taken in with ease. In fishes there exists a remarkable concentration of imj)ortant organs in the fore-part of the body. The head contains, not merely the brain and organs of the senses, but, in addition, the heart and gills ; we find, accord- ingly, that the haemal arches are commensurate in size with the presence of the important parts which they sup- port and protect. In the words of Professor Owen, "Brain and sense-organs, jaws and tongue, heart and gills, arms and legs, may all belong to the head ; and the disproportionate size of the head, and its firm attach- ment to the trunk, required by these functions, are pre- IN THE STRUCTURE OF THE SKELETON. 197 ciselv the conditions most favourable for facilitating; the course of the fish through its native element." In the whale, the vertebrae of the neck are joined into one solid column. By this arrangement, greater protec- tion is afforded to the nervous cord, as this large and heavy animal ploughs its way Avith rapidity through the water. Flexibility in the neck, not needed in this case for other purposes, would have been an inconvenience. The three-toed sloth presents an example the very converse of the last ; the additional vertebras (we have already alluded to it as an example of departure from the tyjiical number) in the neck of this animal are ad- mitted to have a relation to its habits ; in the words of Professor Bell, " the object of the increased number of vertebrae is evidently to allow of a more extensive rota- tion of the head ; for, as each of the bones turns, to a small extent, upon the succeeding one, it is clear that the degree of rotation of the extreme point will be in proportion to the number of pieces in the whole series."* But, in addition, as this animal spends its whole life on trees, clinging to the branches with its powerful limbs, and feeding on the twigs of its arboreal dwelling-place, the length of its neck gives it an advantage in better en- abling it to reach the tender and extreme branches. In carnivorous animals, having four limbs fitted for seizing and holding their living prey, and a mouth armed with strong teeth for tearing it, the neural spines and transverse process of certain neck-vertebrfe are highly developed, so as to become commensurate with the power of the oblique muscles of the head, which are in them of great strength, to enable them to perform their impor- tant functions. In otlier words, the levers supplied by certain elements of the neck vertebrae are in direct pro- ♦ Cyclopicdla of Anatomy ami Physiology, Article Edentata. 198 SPECIAL ADAPTATIONS portion to the active organs of motion, that is, the muscles, which require them as mechanical powers. In buxls, the fore-limbs are used in flight, and the function of the arm is transferred to the neck, that of prehension to the beak, which supplies the place of the hand. The neck is the only flexible part of the verte- bral series, and motive power is abundantly provided for on the same principle as we have seen it to be in the sloth. It is curious to notice that there is a departure from the number seven, so constant in mammals ; the vertebras ranging from nine in the sparrow to twenty- three in the swan. The mode of connexion of the ver- tebrge is also such as to admit of the utmost freedom of motion. In the dorsal portion of the vertebral series, we may also note a few striking adjustments. In certain mam- malia, as the ox, deer, camel, &c., owing to the weight of the horns and antlers, or length of the neck, continued muscular exertion would be necessary, in order to retain the head in its natural position. Such disadvantages is obtained by the presence of the part called pax-wax, or ligament of the neck — composed of yellow elastic fibres — which acts as a natural spring, and obviates the need of constant voluntary muscular effort. Accordingly, we find that certain neural spines in the back (as well as in the neck) are greatly elongated, to give attachment to the remarkable organ referred to. In the aurochs, for example, some of the dorsal vertebras have neural spines which are actually longer than some of the ribs. Such modifications are, indeed, generally observed in browsing animals. As in the fish, excessive development of certain parts of the skull is a provision for the forward position of the heart and gills, so in air-breathing animals the lower IN THE STRUCTURE OF THE SKELETON, 199 arclies of certain other vertebra; are highly developed, forming the ample thorax or chest, for the protection of their heart and lungs. In the neck of the bird we have seen that flexibility is necessary; in the back, firmness is the essential requisite, and we observe there union of ver- tebrae. Further, the hromapophyses, which in man and others are cartilaginous, become in the bird converted into bone, and the united hfemal spines from the keel of the sternum or breast-bone, the extent of the surface pre- sented by which is directly as the development of the powerful muscles which are attached, and directly also, of necessity, as the powers of flight. In the ostrich, and cursorial birds generally, which cannot fly, the haemal sj)ines do not form any crest. In birds, we also observe union be- tween the vertebrne of the loins, an /i/[\ arrangement admirably calculated to give firm support during the powerful and rapid movements in flight Coalescence of the remaining ver- tebrae, in the adult human subject we have seen to be the usual arrangement, and this — together with size particularly in the sacrum — appears to have relation to the erect posture of the body. In many mammalia, the sacrum is proportionally narrower than in man, and coalescence of vertebne is not the law ; but in certain species, which have the faculty of assuming the erect or semi-erect posture, as some monkeys, bears, and certain rodents, the sacral portion of the skeleton is pro- portionally stronger than in others which have no such * Via. 40. Thoracic Hcsmcnt or vertebra of raven. The hieinal arch is ample In ac- conlanoe with ltn functions as a protector of heart, lun^s, &c., and as furnishing surfaces for attachment of po-vcrfiil muscles. References are sainc as In preceding figures. 200 SPECIAL ADAPTATIONS faculty. The permanently separate condition of the sacral elements in the beaver is an arrangement admir- ably suited to its peculiar habits, " using, as it does, not only its long and powerful tail, but even the whole pos- terior half of the trunk, as an organ of propulsion through the water."* In man, as we have already seen, the terminal portion of the spine, forming the coccyx, consists of a few small pieces, j-educed to little more than the centrum or body of the vertebra. But in many of the lower animals, the tail performs important functions, and attains higher develop- ment. Sir John Eichardson, in his account of a journey through Prince Rupert's Land, mentions a curious case of departure from the usual type in the bovine family, which is generally characterized by the high development of the terminal portion of the vertebral series. He says, " The musk-ox has the peculiarity, in the bovine tribe, m the want of an evident tail ; the caudal vertebras are only six in number, being very fiat, and nearly as short, in reference to the pelvis, as in the human species. A tail is not needed by this animal, as, in its elevated sum- mer haunts, moschetos and other winged pests are com- paratively few, while its closer woolly and shaggy hair furnishes its body with sufficient protection from their assaults." The special modifications of the elements of the caudal portion are numerous, and have an obvious reference to final cause or end to be served. In the human coccyx there is no heemal arch. In the tails of not a few ani- mals, lower in the scale, it is distinctly formed of heema- pophyses and haemal spine. The prehensile tails of the spider monkeys, the powerful oar-acting tail of the beaver, and the supporting pillar-like organ in the kan- * Coote on Homologies of Skeleton, p. 61. IN THE STRUCTUEE OF THE SKELETON. 201 garoo, present individual peculiarities of the vertebral elements admirably suited to the different uses of the part. In the kangaroo the lower surface of the tail is subject to pressure, and the same is true of the prehen- sile tails in Phalangista and the opossum, and in all these the hffimal arch is well developed, in order to protect the blood-vessels. " In Petaurus, Phascogale, and Dasyurus, the tail acts as a balancing pole, or serves, from the long and thick hair with which it is clothed, as a portable blanket, to keep the nose and extremities Avarm during sleejj. The ha3mal arches in the tails of these are not so largely developed as in the kangaroo &c., their mecha- nical office of defending the blood-vessels of the tail from pressure not being required."* It is admitted that the typical structure may be departed from by excess in the number of the elements ; if it can be shewn that such departure has decided relation to the habits and wellbeing of an animal, it appears to us a powerful argument in favour of com- bined order and adaptation ; we may here adduce a few examples. Seals and penguins are not fitted for general sojourn and progression on the land, nevertheless they do occa- sionally frequent the shore, but their movements, under such circumstances, are peculiar. One of the highest authorities to which we can refer, specially alludes to these animals, and to modifications in certain vertebrae related to the habit in question. In the Greenland seal, Professor Owen describes processes superadded to the lower surfoce of the lumbar vertebni;, (liypai)opliyses,) "indicating great development of anterior vertebral mus- cles, relating to peculiar gasteropod progression (ni land. In penguins, similar liypapoidiyses attain their maximum * Owen, In Proceedings of Zoological Society, 1888. 202 SPECIAL ADAPTATIONS of development, and have an analogous function to that m the seals, extending the surface of attachment of the powerful muscles on the ventral aspect of the vertebral column, which act in the shuiSing gasteropodal move- ments." ■'•'■■ In the armadillo, wliose bony armour (giving to the animal its name) is of considerable weight in proportion to the size, and serves as a defence against its j)Owerful foes, we find two additional spines (metapophyses) de- veloped, one on each side of the neural spine, upon the principle that three points are better fitted than one to support a superincumbent weight. Certain serpents feed upon the eggs of birds; their teeth are few and feeble — for if the shell of the egg had been broken in the mouth, the want of flexible lips would have occasioned loss of the nutritious contents. Besides, these serpents follow the law of their congeners ; loose attachment of cranial ele- ments, as we have shewn, enables them to take their food entire. The egg, being thus received, is ripjied open as it passes along the gullet, and this is effected by a con- trivance no less remarkable for its simplicity than for its efficiency. Sharp projections (hypapophyses) from cer- tain vcrtebra3 of the neck, perforate the tube of the gul- let, are capped by hard enamel, and effectually perform their proper office. We shall close this part of our subject by alluding to two notable instances of special modifications pervading almost the whole skeleton in serpents and tortoises. In the former we find a long series of vertebras, some of whose elements supply the place of limbs, which are generally wanting, or, if jiresent, as in boa, so rudimen- tary as to be incapable of performing their usual func- tions. The plcurapophyses have free motion, and act as * Professor Owen, in Philosophical Transactions, 1851. IN THE STRUCTUKE OF THE SKELETON. 203 efficient organs in progression on a hard surface, by- means of the laro;e scuta or shield-hke scales covering; the belly of the animal. These scuta form a number of movable broad surfaces, bearing the same relation to the ends of the ribs which hoofs do to the ends of the toes. In pelagic serpents which swim by lateral motion of the tail, the pleurapophyses are more freely movable in a lateral than in a backward direction, j^rogress in the water being accomplished by rapid lateral curvatures of the tail and body. The neural spines of the dorsal ver- tebra? are small, those of the caudal portion large and compressed, and gradually lessening in size to the point of the tail — a peculiarity of these vertebral elements in strict harmony with the general comjjressed state of the body, and that of the short but strong and flat tail, which acts as an oar for propelling, as well as a rudder for guiding.* The spinal colunm of the Ophidia shews the maximum of number of the different vertebrae, and of flexibility as a whole. In the words of Professor Owen, "At first view, the principle of vegetative repetition seems to have exhausted itself, in the long succession of incomplete ver- tebras which support the trunk of the great constrictors ; but by the endless combinations and adjustments of the inflections of their long spine, the absence of locomotive extremities is so comjjensated that the degraded and mutilated serpent can overreach and overcome animals of far higher organization than itself; it can outswim the fish, outrun the rat, outclimb the monkey, and out- wrestle the tiger ; crushing the carcase of the great Carnivore in the embrace of its redoubled coils, and prov- ing the simple vertebral column to be more efifectual in the struggle than the most strongly-developed fore-lunbs, ♦ Dr. Cantor, Transactions of the Zoological Society. 204 SPECIAL ADAPTATIONS with all their requisite rotatory mechanism for the effective vkried application of the heavy and formidably armed paws."* As the sei-pent shews us the highest possible flexibility, so does the tortoise exhibit the greatest rigidity and in- flexibility of vertebral elements, intended also to accom- plish an end necessary to the wellbeing of the animal. The carapace or upjjer arch, and plastron or floor, of the turtle's or tortoise's shell may be compared to the skull ; to use the expression of Professor Owen, it is actually "an abdominal skull, formed of the centra of back, loins, and pelvis united together, their pleurapophyses, hasmapophyses, and other elements, being expanded and laterally adherent ; appendages of the skin — the der- mal bones — are connate with some of the vertebral elements, the whole forming a defence to a well-deve- loped system of haemal organs, heart, lungs, and alimen- tary canal." DIVERGING APPENDAGES OR LIMBS. These assume various forms, from the simple structure which we have noticed in the thorax of the bird up to the perfectly developed limbs of man. Among them re- markable modifications present themselves, having evi- dent reference to the uses of the member, whether for grasping, supporting the body, flying, swimming, leaping, or burrowing.-j" The inference from all these adapta- * Owen on Nature of Limbs, p. 96. ■t In a former paragraph (p. 185) we have shewn evident traces of community of form In the elements of the vertebra and Its appendages ; in reference to the modifications of the latter, it will be necessary here to allude to the very ingenious but, we think, over- strained, views of M. Gervais — (Ann. dcs. Sc. Naturelles, 1853.) According to Duges, there is an arithmetical progression in the number of the parts from arm to fingers, and from thigh to toes, viz., arm and thigh, each of one piece, leg and fore-arm, each of two pieces; in wrist and ankle, hand and foot, fingers and toes, the number five prevails we have therefore the progression, 1, 2. 5. M. Gervais thinks he finds proof that in IN THE STRUCTURE OF THE SKELETON. 205 tions of means to end cannot be explained away by affirming that the animal, finding that it has an organ suited to a certain piu-pose, uses it for that pur})ose. For in the first place, the creature is compelled to a certain mode of life by its instincts, which are altogether differ- ent from its limbs or any of its organs ; and, secondly, its limbs are suited to its other organs, and all its organs are suited to one another. There is in all this no wis- dom or foresight on the part of the animal, but there are arrangements made for its welfare by a Power above it, causing independent organs and instincts to concur and co-operate. It may be laid down as the common rule that the pec- toral and ventral limbs are appendages of the fourth and twenty-six se^-ments of the vetebral series.'* The oc- cipital is always the fourth vertebra, the jielvic may be less constant in its position. But displacement of verte- bral appendages from their typical position in the skele- ton is not uncommon, and will generally be found to be a provision for some peculiarity of function. In most fishes, the pectoral fins, which are its arms, occupy the tyjiical position, being in connexion with the occipital vertebra, whereas in man, and many other animals, the same limbs are removed from their natural position, and are attached to the upper part of the chest. These dif- ferent dispositions arc admitted to be, in the one case as in the other, admirably adapted to the necessities of the animal. Professor Owen, referring to such modifica- tions, remarks, " Wherever either arch with its appen- dages may be situated, it is in its best possible place limbs of vcTtcbratii tlie number five prevails even in the arm and fore-arm, tliigh and le;,', and that tbcrefore there is union of bones in these parts. If this view sliould prove to be correct, Bueli union may be considered as a special modification of the type in re- lation to the functions of tlieparta. • Wc adopt here the views of Professor Owen. 206 SPECIAL ADAPTATIONS in relation to the exigencies and sphere of life of the sjjecies,"-'' "We may next examine some of the principal modifica- tions of the diverging appendages themselves, and of their elements, traces of a general plan having already been pointed out, and proofs adduced that law and order pre- vail also in departures from the type. Although the limbs of animals are diverging appendages of the typical vertebra, all such appendages do not necessarily perform the functions of limbs. Their simplest and most rudi- mentary condition has been already alluded to as they are seen in the thorax of the bird, where they appear to serve merely the purpose of giving additional strength and firmness to the ribs, (pleurapophyses,) from which they originate. In the head of the fish we observe them offering greater advance in development, and in beautiful harmony with their proper function. Those of the third or parietal vertebra constitute the parts called, technically hrancM- ostegals, which, in most fishes, support a flap, whose function is to assist in protecting the gills, and regulat- ing the admission of fresh currents of water to these important organs. The diverging appendages of the second cranial vertebra are modified to form the opercu- lar bones which together constitute the framework of the gill-covers, by the movements of which the amount and direction of the respiratory currents are principally deter- mined. The corresponding part in the anterior segment of the head consists of two pieces called loterygoids, the outer of which serves as a means of connexion between the heemal arches of the first and second vertebrae. How different, then, the forms and uses of corre- sponding appendages in the head of the fish, for, in * Owen on Limbs, p. 81. IN THE STRUCTURE OF THE SKELETON. 207 contrast with those just mentioned, we observe the appendages of the fourth or occipital vertebra forming the pectoral fins, which correspond to the upper limbs in man, and perform an important, though not the prin- cipal part in aquatic progression. The beautiful harmony which subsists between the uses of the pectoral fins and their peculiar structure, has been so frequently and fully discussed in Avorks of Natural Theology,* that it would be needless to go over the same ground here. In tlie frog-fishes, which have the power of moving on the ground when left by the receding tide, in the expanded pectorals of the flying-fish, acting as parachutes during its powerful aerial leaps, in those of the climbing perches of the tropics, and in tlie ordinary forms presented by the fins of most fishes, we observe modifications of parts constructed after the same model, but each in striking imison with the habits of the animal. In the fish, then, the fore-Hmbs (pectoral fins) are the diverging appen- dages of the occipital vertebra, and occupy their natural position as such, (that is, are placed far forwards,) being attached to the hind-head. In other vertebrata, the arch which supports them is transferred from its normal place to the upper part of the trunk, and this transference, and the structure of each piece, arc admitted on all hands to be in complete harmony with the function of the limbs, and necessary to the comfort and wellbeing of the animals. In birds, for example, the parts supporting the ante- rior limbs are modified, so as to fit the diverging appen- dage, to become an organ of flight. It has been already mentioned, that the scapula and coracoid arc respectively pleurapophysis and hamiapophysis of the occipital ver- tebra, and the clavicles or collar-bones the h;emai)ophyses of the atlas, or first cervical vertebra. The relation of ♦ See Palcy ; also Bell oa the Hand, Hogct's BrUljic water Troatlso, . 401. JO 218 TRACES OF SPECIAL ADAPTATION arrangement in these permanently-growing molars, " they are curved, and the j^ressure during mastication is thus not directly transmitted to the formative pulp."* In carnivorous animals, certain teeth are admirably fitted for seizing, holding, and destroying the living prey, and others for dividing it afterwards. The incisors are of the typical number, and therefore more numerous than in many other mammalia, and they often present a tran- sition in general form towards the canines. These latter are large, sharply conical, and of great strength. Some of the molar teeth present remarkable modifications. The fourth premolar in the upper, and the first molar in the lower jaw, are large and sharp-edged, so that when they are moved in opposition to each other, they cut like the blades of scissors ; their function is sectorial, and they are admirably fitted to divide flesh. The concur- rence of independent circumstances is seen in this, that the instincts of these animals lead them to eat flesh, the teeth are exactly suited to such food, their stomach is able to digest it, and the structure of their limbs enables them to seize and hold it. The hyasna obtains its food from the harder parts left by other carnivora, the bones of animals forming its chief sustenance ; and the teeth are modified in harmony with its habits, presenting a re- markable deviation from the usual typical form in the carnivorous division to which the animal belongs. Cer- tain of the premolars in upper and lower jaws are large and conical, and have at the base, near the line of the gum, a thick belt or ridge, which serves to protect that part during the process of crushing the hard bones. Professor Owen states that such a tooth, when shewn to an experienced engineer, was declared by him to be a per- fect model of a hammer for stone-breaking. * Owen's Odontography, p. 402. •-^ THE NUMBER, FORM, AND STRUCTURE OF TEETH. 219 In true vegetable-feeding, hoofed mammalia, we find remarkable interblending of dentine, enamel, and cement, in the molars, the proportions of each in different cases varying, as well as the pattern presented by the crown of the teeth. A general idea of such arrangement, and of its consequences, (roughness of surface,) may be obtained by inspection of the old molar teeth of an ox or sheep. In such animals also, owing to the peculiar mechanism of the joint of the lower jaw, there is very free motion in various directions, and thus the whole triturating surface of the teeth, so well adapted to their function, is readily available. In the elephant, several curious modifications may be observed in the large molar teeth. Each is composed of a number of connected plates, having the usual arrange- ment of dentine, enamel, and cement substances, the latter being at first the binding material by which the plates are tied together. '• The formation of each grinder be- gins with tlie summit of the anterior plate, and the rest are completed in succession ; the tooth is gradually ad- vanced in position as its growth proceeds, and in the existing Indian elephant, the anterior plates are brought into use before the posterior are formed."* In all ele- phants, the molars succeed each other from behind for- wards, moving in a curve, the young growing tooth being nearly at right angles to the one already in use. Pro- fessor Owen's statement is so much to the jjoint that wo shall quote it entire, " The jaw is not encumbered with the whole weight of the massive tooth at once, but it is formed by degrees as wanted ; the subdivision of the crown into a number of successive plates, and of these into Hubcylindrical processes, presenting the conditions most favoiualjle to progressive formation. Subdivision ♦ Cyclopa-'dla of Anatomy Art. 1'oeth. 220 TRACES OF SPECIAL ADAPTATION of tlie tootli gives another advantage, each part, like a simple tooth, has dentine, enamel, and cement. The dif- ferent parts of the tooth, as they come forwards, have, of course, from differences of attrition, different kinds of surface, the anterior portion for crushing branches, the middle, with its transverse ridges, for reducing these to smaller fragments, and the posterior tubercles of enamel grind it to a pulp," Such special modifications of masticating organs, according to the gnawing, flesh-eating, or vegetable- grinding habits in different animals, are sufficiently ob- vious, but not more so than the peculiarities of organs fitted for mixed food, as in human beings. In his dentition, man presents a character intermediate be- tween the carnivorous and the herbivorous type ; " the presence of canines, and the absence of complex struc- ture, arising from interblending of vertical plates of the different dentinal tissues in the molars, would prove that the food could not have been the coarse, uncooked vege- table substances for which complex molars are adajjted ; and, on the other hand, the feeble development of the canines, and the absence of molars of the sectorial shape, and opposed like scissors' blades, would equally shew that the species had been unfitted for obtaining habitual sus- tenance from the raw, quivering fibre of recently killed animals."* How evident, therefore, the relation between the kind of food which man naturally makes choice of, and the organs which bruise and prepare it for the act of digestion in the stomach ; there is assuredly no mere ac- cidental coincidence in all these arrangements. The Ophidia, (or serpent order,) as has been already stated, take in their prey entire, and their teeth are gene- rally simply conical, and fitted for retention. The poison * Owen's Odontography, p. 471. IN THE NUMBER, FORM, AND STRUCTURE OF TEETH. 221 fangs of certain species are particularly worthy of notice, and certain non-venomous species are instructive as pre- senting a transitional form. Some of the teeth in the upper jaw, in certain kinds of serpents, present a longi- tudinal oToove which serves to conduct an acrid, hut not deadly saliva, into the wounds which they inflict. The true venomous fang, such as that of the rattlesnake, is just a flat tooth folded on itself, and the edges united ; the hollow or canal which traverses it is in communica- tion with the poison-gland at its hase, the nuiscles cover- ing Avhich being in powerful action during attack, com- press the gland, and squeeze its deadly contents into the wound inflicted by the fang. When not in use, these formidable weapons are retracted and concealed in a fold of the gum, with their points directed backwards ; the relation of tooth, jaw, and other parts, is sufficient to un- cover the recumbent fong, and bring it into use when re- quired. In fishes, special adjustments are as numerous and remarkable as in higher vertebrata. Those that feed on worms, and similar soft food, have teeth which are simpl}- conical, and difliering in number and size according to the minor modifications of liabit ; the barbel and others present such a form of dental apparatus, well fitted for simple capture and retention of the food. The wolf-fish, again, has a dental furniture suited for bruising the shells of the mollusca on which it feeds ; the tliiu mem- branous stomach of that species shews that tlic pavement of bruising tectli, with which its mouth is lined, serves for the effectual comminution of its prey, rendering the presence of a gizzard unnecessary. The fishes which feed on the coral-building animals have parrot-like jaws in front, f )r Ijreaking olT the calcareous po]y])i(loms, and on llic |iliai7ngeal bones behind, an apparatus to crush and 222 TRACES OF SPECIAL ADAPTATION IN TEETH. prepare for digestion in the stomach. The pharyngeal teeth of the wrasse are each in the form of an arch of greath strength, admirably fitted for the process of crush- ino-, " if the engineer would study the model of a dome of unusual strength, and so supported as to relieve from its pressure the floor of a vaulted chamber beneath, let him make a vertical section of one of the crushing pha- ryngeal teeth of a wrasse."* In the carnivorous Sphyr- aena, whose teeth are liable to injury during eiforts to secure its living prey, these formidable organs are conti- nually replaced, the alternate teeth being shed cotempo- raneousl}^, by which provision is made for having a series of offensive weapons always ready for use. The position of teeth, also, in this class, is in strict conformity with the habits and general organization. Those of flat fishes (flounders, &c.) are unequally distri- buted, being most numerous on the side next the under surface of the animal ; in other words that side of the jaws next the ground, (in the usual position of such fishes,) being the one nearest their food, which is under them. It appears, then, that in these instruments, as in every other part of the animal frame, while a general plan sub- ordinates the whole, there is, at the same time, a vast number and variety of modifications, each in beautiful harmony with the instincts and habits of the animal, with all its organs, and with the place and part assigned to it by its great Author. * Owen's Odontography, p. 788. CHAPTER VI. MOLLUSCA. SECT. I. TYPICAL FORMS OF MOLLUSCA. We have, in the preceding pages, been directing atten- tion to animals possessed of an internal skeleton formed of parts constructed according to a common plan. We jjass to the examination of others generally characterized by the absence of such a framework, but often present- ing hard parts on the outside, constituting exoskeleton. It is admitted that there are three types of inverte- brata : the molluscan, as the oyster, etc. ; the articulate, such as insects and crabs ; and the radiate, comprehend- ing the star-fishes, etc. Altliough much remains to be done in reducing these departments of the animal kingdom to the same philo- sophical order which the department of the verlebrata has attained, we shall find no lack of examples for illus- trating the argument, some of the more obvious and prominent of which may now be examined. We begin with mollusca. The investigations of observers on the Continent and in our own country, have demonstrated that in the ear- lier periods of life, the mollusca i)resent symmetry of parts in reference to a vertical and longitudinal ])lane. An examination of tlio history of development in the 224 TYPICAL FORMS mollusc has shown that in early life there is a short com- pressed body, destitute of any lateral appendages, and presenting no roj^etition of segments. In the skeleton of the vertebrata, it is necessary to ob- serve the relations of its parts to the neural and hasmal organs, which are protected by it. The superior and in- ferior region of the molluscan animal must also be deter- mined in order that the relations of parts in the arche- type may be understood. In vertebrata, the dorsal or superior aspect of the body corresponds to the position of the central mass of the nervous system, the htemal being inferior. There is some difference of opinion as to the relations of the parts in the mollusca.* Adopting the view that the neural side is also the lower or ventral, and the heemal the Fig. 45. t superior, we proceed to examine the archetype, our mate- rials being chiefly drawn from the admirable treatise of Professor Huxley on this subject.^ * Professor Allman on the Homologies of the Tunieata and Polyzoa. Transactions Eoyal Irish Academy, 1S52. t Fia. 45. Ideal archetype, or common plan of the mollusca. w, the mouth ; a, the anal aperture, or extremity of the intestine; H, h tmal region; A, the heart; 6, branchiae >r gills; N, neural region; n, n, n, ganglia or nervous centres; ep, epipodiiim or upper uot; pp, propodium, anterior part of foot; m.s, mesopodium, middle part; vif, metapo- .lium, posterior part; pp, mx, and mt, together constitute the loot in general language. t Transactions Uoyal Society, 1S53; see also Knight's English Cyclop rdia, Art. ifoUmca. OF MOLLUSCA. 225 The archetype mollusc is supposed to be bilaterally symmetrical ; the relations of the different parts will be understood from the accompanyng figure. The ha3mal region (H) coiTCsponds to that where the heart {h) is situated ; the opposite is termed neural, and the great nervous centres (n n n) arc usually placed in it. The anterior part of the body is marked by the position of the mouth, (771,) the posterior by the opposite opening of the alimentary canal or anus (a.) The lower or neural surface is usually called the foot, because generally em- ployed as an organ of progression. The foot may be divided into three portions, the propndium (pp) or fore- foot ; the mesopodium (ms) or middle foot ; and the metapodium (mt) or hind foot. The upper part of the foot, or middle region of the body, sometimes is prolonged into a fold or enlargement on each side below the point of junction of the hfemal and neural regions ; this prolongation is called epipodium, (e/9.) On the lateral and superior part of tlie head are two pairs of appen- dages, the eyes and tentacles. The part usually called mantle or pallium in mollusca, consists of a free fold of the skin either behind or in front of the anus. In the figure the branchitB or gills {b) lie behind the heart, (7i.) There are two princij)al modi- fications of this common plan depending mainly on the relative development of certain parts of the haemal region. The portion of it in front of the anus is called abdomen, that behind it is called post-abdomen. Excessive deve- lopment of the former, accompa- *""'■ '**'• * • Fio. 4G. Neural niodiOcallon of archetype mollusc. Tho mouth, Blomnch, and ali- mentary cinal are Hhaded. Here tho part of tho Iwmal roKion abovo, or hi front of tho canal opening, H hl;,'lily developed ; the aliniontary canal having' a concavity toward tho neural Hurfaco 226 TYPICAL FORMS OF MOLLUSCA. nied by a bend of the intestine into it, (tlie concave part of wliich is directed downwards, or towards the neural surface,) constitutes a neural flexure. When the post- abdomen becomes developed in the same way, the open part of the intestinal bend will be directed towards the haemal surface, giving rise to a hcemal flexure. Professor Huxley considers, therefore, that there are two primary modifications of the molluscan archetype, which may be termed the Neural and Haemal plans. Fig- 47. * Tlic prcsencc or absence of a shell is of minor importance, and does not affect the re- lations of the archetype ; all mollusca, therefore, may be referred to the same common typical form. The cuttle-fish, with its formidable prehensile arms and beak ; the singular Clio ; the sluggish oyster ; the more active pecten or clam ; the destructive teredo or ship-worm ; those expert tunnel-makers and borers, spe- cies of Pholas and others ; the slug and garden snail ; the pearl oyster ; — in a word, the almost endless forms of this great division of the Invertebrate sub-kingdom, may all be considered as framed after the same model, and we shall find that certain modifications of it have undoubtedly reference to the habits and mode of life of the animals. * Fig. 47. ITaenial modifications of arclietype mollusc. Shews excessive development of post-abdomen, the part behind or below the anus. The alimentary canal has a flex- ure toward the hasmal region ; in the fig. the heart is seen in the concavity of the flexure. MODIFICATIONS OF THE ARCHETYPE MOLLUSC. 227 SECT. II. MODIFICATIONS OF THE ARCHETYPE MOLLUSC. Ccplialopoda^ or cuttle-fishes. These remarkable ani- mals are usually placed in the foremost ranks of the moUuscan type, and they present several interesting points of structure. The appendages, (whose position has given rise to the name Cephalopoda, or head-footed,) provided Avith a greater or less number of discs, each acting as a sucker, enabling them to retain their living prey and resist its struggles ; their formidable beak-like jaws, by which they tear their prey in pieces ; their bag, from which they explode an inky cloud, under cover of which they escape from their pursuers ; their funnel, w'hich serves as a discharge-pipe for water which has been in contact with the gills, and which, by the force of its escape, assists in aquatic progression ; their highly- developed and curiously-constructed eyes — all give them a high degree of prominence in the estimation of the naturalist. They are pre-eminently the Felidpe of the ocean : lying in wait for living prey ; lurking in secrecy to spring on it ; feeding chiefly in the twilight or at night ; while their strength and rapidity of movement render them formidable enemies to many of their fellow- inhabitants of the ocean. They are, moreover, the chame- leons of the deep, having the power of rapidly changing the colour of their skin as emergencies require. What special modifications do they present, as departures from the model ? and what relations do such bear to the habits of these animals ? These are questions which may be now briefly examined, so far as the results arrived at by ob- servers enable us to speak. It is ndmitti'd lluit the development of all animals is sul>ject to strict law, and the results of inquiries in this direction enable us to indicate the real nature of parts 228 MODIFICATIONS OF THE whose homology, in reference to the archetype, may seem difficult to solve in the fully matured condition. It has heen already stated that the Cephalopods are so named from the position of certain organs, which, although chiefly emplo3'ed for prehension and retention of prey, are nevertheless also capable of being used as means of progression on a hard surface. Designations of parts are not always in strict accordance with their true nature, but it so happens in this particular instance, that the term Cephalopod is homologically correct, for the appendages which surround the fore-part of the animal in reaHty correspond to the lower surface or foot, being ac- tually lateral appendages of that part. These organs vary in number ; in some species there are eight, in others ten. In the well-known Argonaut, two of the appendages are webbed, so as to present considerable ex- tent of surface. These were described by Aristotle as the sails of the animal, which, in fine weather, and when floating on the surface, it expanded and raised to catch the wind — a description which, as it is now well known, does not indicate the true use of these parts ; for their function is to form the shell, and progression is accom- ]3lished by the forcible ejection of water from the funnel, the animal being urged on its course by the recoil. * Fig. 48. Plan of cnttle-flsh, to shew its relation to the archetype, pp, ms, ml, the parts of the foot modifled to form the arms which surround the head; ep, epipodium forming the funnel through which water is discharged. The alimentary canal and heart will be seen in the middle of the shaded part of this figure. ARCHETYPE MOLLUSC. 229 In those with ten appendages, two are longer than the others, and serve as anchors to moor the body, or arc darted out to capture prey beyond reach of the ' shorter arms. Allusion has been made to the fmictions assigned to the funnel ; tliis part, so necessary in the economy of the animal, may be also referred to its corresponding part in the archetype. It is derived from the epipodium, upper foot, {Fig. 48. ep,) the posterior part only is con- sidered by Professor Huxley as contributing to the for- mation of this important organ. ^' The mouth is thrust back between the halves of the mesopodium, the propo- dium and mesopodium forming a continuous sheath — bearing tentacles — around the oral aperture. The two halves of the epipodium united form the funnel."* Pteropoda. — The animals so denominated are gene- rally of small size, but this is compensated for by their numbers. In the tropics, as well as in the Arctic seas, they abound, and, with other marine invertebrata, serve to stock the pasture-grounds of the great whales. The peculiar appendages, or lateral flaps, from which they derive their name, {Pteropoda, wing-footed,) are the principal means of progression by which they flit hither and thither — whence they have been apj)ropriately called the moths and butterflies of the ocean. As littoral productions they are not generally known, excepting from the shells of some which are occasionally cast up ; but in the open sea, far from land, they are sufficiently familiar to the observant naviirator. In these interesting molluscs, the parts called fore, middle, and hind foot, are generally in a rudimentary condition, and the epipodium or upper foot forms the wing-lilcu appendages so necessary in the act of progres- ♦ Knigbt's English Cycloptcdia, Art. MoUwca. 230 MODIFICATIONS OF THE sion, and giving such a marked cliaracter to these ani- mals. Cleodora, Euribia, Clio, Pneumodermon, and others, present each peculiar but minor modifications of the epipodium, doubtless in harmony with the habits of the respective species, but, nevertheless, essentially of the same nature, and performing the same general function. The epipodium, which is but a narrow band in the archetyj^e, appears, therefore, to attain its maximum of development in certain Pteropods, and forming wing-like appendages copiously traversed by strong muscular fibres, is admirably fitted to be employed as oars, and the testi- mony of observers confirms such idea respecting its use. — There are other mollusca not far removed in appearance from those just described, which also deserve to be no- ticed here as examples illustrative of the argument. They have been called Heteropoda. Like the Pteropoda, they are constituted for free progression in the water. The relations of their parts have been very fully examined by Professor Huxley in the Essay already quoted. The body in one genus, namely, Firola, is clear as crystal, so that all its internal organs can be distinctly seen, and the author quoted describes it "as hardly distinguishable in the water, except by the incessant flapping of its flattened ventral appendage." The shape of this organ, by which the animal makes progression in the water, is that of a cheese-cutter ; it is a modification of the proj^odium or fore-foot of the archetype, the other parts remaining rudimentary. In another genus, viz., Atlanta, progres- sion in the water is accomplished by means of an appen- dage similar to that of Firola, and a modification of the same part, thus remarkably constituted to serve an im- portant end in the economy of the animal. But Atlanta has the power of attaching itself to marine j)lants by means of a sucking disc placed behind the propodium ; ARCHETYPE MOLLUSC. 231 this part is the mesopodiiim, which thus presents a mo- dification different from that of the propodiiim, the' one as "well as the other, however, being admirably suited to its function. Moreover, the metapodium, or tail, as it is sometimes called, bears on its surface the hard body called operculum, which serves as a lid to close the mouth of the shell when the animal retreats into that appen- dage. In Aplysia, or sea-hare, the epipodium is highly de- veloped for a special purpose, namely, to assist in loco- motion. Professor Huxley describes a tropical Aplysia as flying through the water in precisely the same way as a Pteropod would do. In Xatica, we observe the meso- podium modified, to serve as a disc for locomotion by creeping ; the metapodium bearing the operculum or lid which closes the mouth of the shell when the animal takes refuge in it. Among Bivalves, as they are called, from the form of the protecting shell, we find numerous modifications of the neural surface in evident relation to tlic wants of the animal. In the oyster, destined to sedentary hfe, it is small ; in Solen or razor-fish it is large, constituting the foot, which the animal employs as an effective means of bui'jang itself in the loose sand. According to the views of some, the same part is actually so modified in its form, and in the nature of its constituent tissues, that it may be used as an instrument for perforating wood and rock. Whatever be the form or function of this necessary organ of the bivalve mollusc, it is supposed to correspond to the mctapodiniii oi'the archetype. Certain Gasteropodous mollusca are, when young, pro- tected by a shell resembling that of llie nautilus in miniature. At this stage they do not possess the power of creeping, but swim freely in the water — a provision 232 MODIFICATIONS OF THE ARCHETYPE MOLLUSC, which secures their wide distribution, and gives rise to fresh colonies at a distance from the parent. At this early period of life they are provided with two wing-like appendages fringed with cilia ; these are employed as oars, by which they move from place to place. The ap- pendages in question are believed to correspond to the anterior part of the epipodium. This peculiar modifica- tion is, however, only a temporary arrangement ; a time arrives when it is no longer needed ; it then disappears, and the adult animal accomplishes progression on hard surfaces by means of the foot proper. The ciliated epi- podiiun is provided for a temporary purpose, and when that is accomplished it disappears, to be superseded by another part. It is therefore admitted, that all mollusca present traces of a common plan ; and although in every instance it may not be possible to indicate with clearness and pre- cision the special ends of the many modifications of the archetype, still, arguing from what we do know, it is not unreasonable to conclude that we have here independent members in harmony with each other, and conspiring to promote the wellbeing of the animal in its destined sphere of life. CHAPTER VII. ARTICUL AT A. SECT, T. IIOMOTTPAL RES-QS AND APPENDAGES. We now pass to the Articulate type of tlie Inverte- brata, comprehending crabs, barnacles, insects, spiders, and others.* These agree in one obvious character — their body consists of a series of similar or homotypal rings, which present almost endless variety in size, form, and other particulars, according to the habits of the spe- cies. The rings arc generally, in the higher lands at least, of more or less hard texture, giving support to appendages, and serving as points of attachment to nu- merous muscles, as well as protecting various important organs concerned in the function of sensation, motion, circulation, &c. They present us with examples of a higlily-dcv^eloped outside covering, technically called exo- skeleton, the character of which varies as there is neces- sity in different parts, for variety of motion, for solidity, or for simple protection. The endless diversity in form, and the exquisite beauty of colour and sculpture, exhibited by certain of the Arti- culata, have rendered them favourite objects of study, and their history has been in general very thoroughly * It Is not our Intention to discuss hero all the classes of the Articulate typo ; a selec- tion will sufllcc for our purpose. 234 HOMOTYPAL RINGS investigated by observers in diiferent countries. The fertile results which have accrued from such inquiries pre- sent admirable examples of what may be expected from the patient labours of ardent naturalists, guided by care- ful attention to philosophical methods of investigation. We have stated that all the pieces in the linear series of which an articulate animal is made up, are homotypal, that is, constructed on the same plan. This unity of composition is not necessarily coincident with any law of number, viewing the Articulata as a whole ; but in the higher types, at least, the number of similar pieces of which the body consists is usuallj^ uniform. We may here introduce the general law announced by M. Audoin, in 1820, that the similarity or difference be- tween the segments, the union or the separation of the pieces of which they consist, the excessive development of some and the rudimentary conditions of others, occasion all those differences observed in the entire series of arti- culated animals. It is well established that a common type determines the general organization of the animals in question, and we may now examine the structure of the typical ring or segment. Milne Edwards, in his history of the Crustacea, has demonstrated very clearly the composition of this part. It may be described as consisting of two arches, a superior and an inferior. The former consists of four pieces, arranged in pairs on each side of the middle line. ^10- 49* The two upper, occupying a po- sition on each side of this middle line, are called tergal, * Fig. 49. Plan of ring of Articulate animal, t, tergals ; ep, epinierals; s, sternals; es •••Hsternals. AND APPENDACxES. 235 because forming the back, (from tergum, back ;) tliose on each side are called epimerals, or flank pieces. The lower arch has similar composition : the middle pieces are called sternal, because corresponding in position to the breast-bone (sternum) in A^ertebrata ; the lateral pieces are called episternals. Instead of the technical terms epimeral and episternal, we may use the terms upi)er and lower flanks. In all this we find some resem- blance to the neural and htemal arches in the vertebrate segment, with this diflerence, tliat the body of the ver- tebra serves at once as a foundation and line of demar- cation between the two arches, each of which is complete and independent. The typical segment in the Articulata may be compared to a segment of a tunnel, not merely arched in the roof, but having also a concave floor. A series of such rings constitutes the external framework of the animals under discussion, and protects the nervous centres, which are placed near to tlic floor, and also the haemal organs, which lie beneath the roof, and therefore differ in their position from that in the Vertcbrata. The division of the body, in crabs and insects, into three regions — head, thorax, and abdomen, is generally obvious enough. There may exist diflerence of opinion regarding the number of segments or I'ings entering into the formation of each of these, and respecting the number of pieces constituting the typical ring ; but it is generally admitted as an established truth, that the entire body is made up of a munber of similar pieces. In Crustacea^ (crabs, &c.,) Milne l*]dwards and others believe each region to be made up of seven segments, making, tlierefore, twenty-one in all. In insects, the head is supposed to consist of five, the thorax of three, and the abdomen of eleven. "'•' Erichson, in liis E?itomo- ♦ Nowporl, Art. Innecta, Cyclopiodia of Andtoniy and I'hyslology. 236 HOMOTYPAL KINGS grapliien, has demonstrated that the thoracic portion of the body in crabs, insects, and spiders, is made up of three segments.* But, as we have said, whatever differ- ence of opinion exists regarding the entire number in any one region, or in the whole body, it is universally admitted that a uniform plan regulates the construction of the entire framework ; " the different forms of the body are invariably the result, not of the introduction of new elements, but of the greater or less extent to which the primary parts are developed/'f We have seen that in the vertebrata the typical verte- bra supports appendages ; so the typical ring in the articulate invertebrata also gives attachment to lateral appendages. Their form and function vary according to the part of the body which supports them. They differ also in different species, and even at various periods of the life of the same individual, but they all possess cer- tain common characters. M. Audoin, long ago, demonstrated that the appen- dages in question belong either to the ujoper or lower arch of each ring of the body, the first constitute the wings of insects, and the second their legs ; the same applies to those of crabs and spiders, which, however, want the upper appendages. They are, therefore, arranged in pairs on either side of the middle line, and each ring supports either two or four such appendages. Those of the inferior arch are the more important, and are of more universal occurrence than the others. In Crustacea the complete appendage is constituted by three distinct portions, which it will be necessary briefly * In Dana's Crustacea of the U. 8. Exploring Expedition, there are some peculiar and important views as to the organization of the different groups, and the number of rings in the ditferent regions (head, &c.,) of the body ; as well as the mean normal length of rings. It is, however, unnecessary for our purpose to discuss the subject. + Newport, in CyclopiEdia of Anatomy and Physiology. AND APPENDAGES. 237 to describe. The first and most essential of these is the stem, which gives support to the other two ; it is formed of a number of pieces attached in linear series. The second i)art is called palp, and is generally attached near the base of the stem. The third is called by M. Edwards the fouet, OT JlabeUum ; it also originates from the stem, but at a point more exter- nal than the palp. In conclusion, it may be remarked that attention to the number of appendages in any part sometimes aifords a good crite- rion for deciding its composition, where, owing to adhesion or other circumstances, the number of rings may be obscured Modifications or departures from the general plan may arise from several causes ; — as from soldering of two or more of the elementary pieces ; from confused develop- ment of parts whose presence may be indicated by the existence of special centres during the process of harden- ing ; from wasting of one or more of the elements of the typical segment ; the abortion of certain parts of the same ; unequal development ; overlapping of neighbour- ing parts ; disappearance of typical parts ; and, lastly, from multiplication by repetition of similar parts.f Fig. 50.* SECT. II. SPECIAL MODIFICATIONS OF RINGS AND APPENDAGES. Crustacea. — In the higher forms, usually called Deca- pods, (ten-footed,) from the number of their chief loco- • Fio. 50. Appendages of Crnstaccan, showing Its essential parts; fl, stem ; ft, palp; c, flabclliiin. t M. E'lwanl.t, Annals dcs Sciences Naturclles, 1851. 238 SPECIAL MODIFICATIONS motive members, we observe three principal modifications in the general form of the body. First, there is the Bra- chyura or short-tailed crabs, (as the common crab,) in which the abdominal part of the body is of small size, and usually folded beneath the thorax, (so called,) which part is generally very highly developed. The second form comprehends the Anomoura, in which the abdomi- nal portion of the body is soft and defenceless, as in the hermit crabs. Under the third head are included all those called Macroura, (long-tailed,) the j^osterior extre- mity of the body being well-developed ; the lobster may be cited as an example. Details regarding the real na- ture of the departures from the archetype in each of these three forms are unnecessary for our purpose ; it is enough to say that in every case, the structure, habits, and in- stincts of the animals are all in beautiful harmony with each other. Where, as in the first of these, the thorax is well developed, and usually of great strength, the ambulatory appendages, in five pairs, are generally of large size, and constitute very efficient organs for progression as well as other purposes. The great strength of the general frame- work ij in admirable harmony with its function as a supporter of the powerful limbs, and the protector of important internal organs. But, since the relations of the segments, and of the appendages which they support, are so intimate, the special modifications and functions of each are best studied in conjunction. The tabular view which we here submit, of some of the segments and their appendages, will afford an idea of the deviations from the common plan which occur in different parts of the body of the same individual, and shew how each deviation has reference to some peculiar function of the part. There is an absence of the centralization and OF IlINGS AND APPENDAGES. 239 specialization which characterize animals higher in the scale ; all the segments and their appendages together constitute the individual, and each performs its respec- tive function in order to contribute to the wellbeing of the whole. The following table represents the general arrangement of most of the rings and appendages in one of the higher Crustacea, a lobster, for example : — RufGS. Appesdages. FtlNCTIOXS. 1 2 3 Eyes. 1st, pair of Antennas, 2d, do. do. Vision. • Touch, &c.* 4 Mandibles. ~ 5 1st, Maxilla?, 6 2d, do. Capture and division of 7 8 1st, Feet-jaws, 2d, do. food, &c. 9 3d, do. J 1, 12, 13, 14 Limbs, do. • For progression. Then follow appendages of abdominal rings, varying in use. The individual is thus made up of a number of organs, each of which fulfils a special office ; by this division of labour each most effectively performs its part in the general economy, and the wellbeing of the whole is amply provided for. The typical appendages of the first and second rings are modified for the purj)oses of vision, touch, hearing, &c. ; then follow organs surrounding the mouth, and wliich are emjjloyed by the animal when food is required ; the flaljcllum of the second pair of foot-jaws assists in respi- ration ; the thoracic appendages are limbs for locomotion, and sometimes for prehension ; those of the abdmiien are cither for locomotion or respiration, or are concerned in the function of reproductioji. It is to be t)bservcd tliat • One or both of these are now bellovod to perform tlio function of smelling. 240 SPECIAL MODIFICATIONS each appendage presents special modifications not only in its general form, but also in the number of the ele- ments of which it consists, but in every instance the departure from the typical appendage has a decided rela- tion to its use and the comfort of the animal. In Crustacea of lower organization, the king-crab, for example, the appendages of the head and thorax closely surround the mouth ; they are nearly all of the same form, and act not only as limbs for motion, but also as instruments for the capture of the food, and farther, their bases act as jaws for dividing that food. The mandibles correspond to the stem of the typical appendage, strengthened and usually toothed. In Che- lura terebrans, whose habits of boring render it so destructive to wooden piles, the jaws present a file-like surface, admirably fitted to reduce to powder any such structure. Generally speaking, it may be observed that the ap- pendages of the fourth to the ninth segments inclusive have forms and dimensions varying in harmony with their uses. In the words of M. Edwards, " they are so much the shorter and flatter as they are more peculiarly apportioned to the oral apparatus, a disposition which is nowhere more conspicuously displayed than among the short-tailed Decapods, (common crab, for instance,) in which they resemble horny laminte, armed with teeth of various sizes, and supporting a jointed palp as well as a flabellum,'"- In the thoracic portion of the body, some of the more anterior appendages or limbs are, in the higher Crustacea, of large size and peculiar organization, constituting the pin- cers, which are very formidable instruments for offence and defence, and are sometimes used for other purposes. One * Cyclopaedia of Anatomy, Art. Crustacea. OF KINGS AND APPENDAGES. 241 of the most striking examples of such modification in harmony Avith function, occurs in the large land-crab (Birgus Latro) of the Keeling Islands. We shall quote the description given by Mr. Darwin : — " The first pair of legs end in strong and heavy pincers, the last pair are fitted with weaker and narrower. The animal tears off the cocoa-nut husk, fibre by fibre, and always from that end under which th-e three eye-holes are situated ; when this is completed, the crab commences hammering with its heavy claws on one of the eye-holes till an opening is made, then, turning round its body by the aid of its pos- terior and narrow j)incers, it extracts the contents — a curious instance of instinct and adaptation of structure between two objects so remote from each other as a crab and a cocoa-nut. The strength of the fore-pincers is great : an individual was confined in a tin box, the lid secured with twine, but the crab turned down the edges and escaped ; it actually punched many small holes quite through the tin."*-' In the species of Portunus of our own seas, the last joint of some of the thoracic members is flattened, and the limb serves as a paddle for swimming, or is used by the animal as a means of scut- tling itself in soft sand. In many Crustacea, cer- tain appendages are modified to serve as apparatus for re- spiration, acting, in fact, as F"- 5i.+ branchije or gills. Those called Branchiopods (gill- ♦ Darwin, Journal of a Nuturnlist, p. 403. t Fk;. .')'. TrntiHforrnallon of appendage of abdomen In a Branclilopodous (glll-footod) Crustacean. I', flabcllum; c, palp, wlilch act a.s respiratory organs. 242 SPECIAL MODIFICATIONS footed) receive their name from this peculiarity ; the whole of tlie thoracic appendages are in the form of lamellag, and the parts corresponding to palp and fla- helliim are membranous vesicles highly vascular, and fitted to expose the circulating fluid to the action of the air contained in the surrounding water. In certain others, the Amphipods, for example, localiza- tion of function is more com- plete, ihejlabel- lum alone acting as a gill. In those called Iso- pods, the mem- bers for loco- motion have no other function superadded, re- spiration being performed by the first five pairs of ab- dominal appendages, which appear to have no other use. In the lobster, cray-fish and others, in which tlie hinder part of the body is well developed, certain of its elements are very specially fitted for the progression of the animal through the water. The last ring, and the appendages of the one which precedes it, arc specially modified to form their powerful tail fin. In the soft-tailed hermit crabs, which protect their tender and defenceless abdomen in empty spiral shells of Mollusca, certain appendages are modified to act as hooks by which the animal holds fast to the inside of its borrowed habitation ; and it is a curious circumstance, that some of these hooks are wantins; on one side, since Fig. 52.* ♦ Fia. 52. Appendage of Amphipodous Crustacean, tba flabelluin, c, alone serving as a gill for respiration. OF mXGS AND APPENDAGES. 243 they would be useless or even an encumbrance to the animal, owing to the curve of its body corresponding to that of the shell in which it lives. The instincts of the hermit crab lead it to seek in an empty shell that pro- tection which is wanting in the texture of its own body. The means by which it holds fast are also admirably fitted by form and position, to the exigency of the case. Not a few of the Crustacea are parasites, that is, they attach themselves to other animals, and feed on their juices ; those called fish-lice are examples. Such habits require special peculiarities of organization, and we are constrained to admire the wisdom which foresaw and provided for all tlie necessities of these singular beings. The mouth apparatus in some is fitted at once for pier- cing and sucking the juices of the foster-parent ; and cer- tain of the appendages in other species, corresponding to those already alluded to under the name of foot-jaws, are constructed in such a way that they enable the little animal to keep fast hold of its foster-parent. In the curious Lerneada), whose grotesque forms have puzzled not a few observers, the young are furnished with a well-developed eye, and arc provided with two large pairs of appendages, which serve as oars. Their peculiar instincts lead them to fasten themselves to various fishes, some selecting one part of the fish, others a difierent part. Some after they become fixed, the eye, no longer of any use, is lost, the oar-like appendages either disappear, or undergo a change of form suited to the new mode of life ; in a word, there are several independent successional arrangements concurring to one end. Certain parts are necessary to the existence and comfort of the animal, and such are jirovided, and everything is in conformity with the position which it occupies in the economy of nature. 244 SPECIAL MODIFICATIONS Barnacles. — These remarkable animals, in some one or other of their forms, are doubtless familiar to our readers. Many of them are attached, by more or less flexible stalks, to sea-weeds, to drift-wood, even to quills shed by sea-birds, or they adhere in countless multitudes to the bottoms of ships which enter our harbours from some warmer region ; so abundant are they, in fact, as sometimes to impede the motion of the vessel in the water. Other kinds contribute to the formation of that white line which marks the limit of high-water on our rocky shores, or give a continuous covering to the exposed parts of marine piles or stakes of salmon-nets. Others invariably attach themselves to corals ; not a few find a suitable dwelling-place in the thick skin of whales, and Fig. 53.* certain others in the shell of the sea-turtle, and some bury themselves in sponges. All these curious animals are * Fig. 53. a, A Stomapod Crustacean of tbe genus Leucifer. The abdominal portion is not shaded. The shaded part corresponds with the next, h. 6, Cirriped, or Barnacle — a mature individual. All the parts correspond to shaded portion of a; the eyes and antennw, which are distinct in early life, are also represented here, for the sake of comparison. OF RINGS AND APPENDAGES. 245 constructed on the same general plan as the Crustacea we have been examining, and are, in fact, so nearly allied, that naturalists justly include them in that class. {Fig. 53.) The archetype has undergone remarkable transforma- tions in the barnacles, in order to fit them — and how admirably are they fitted — to that particular part which the Creator has assigned them in the economy of na- ture. In the earlier periods of their life, barnacles are free ; that is, unattached, are possessed of efficient locomotive members, and furnished with organs of vision ; in this condition they very much resemble some of the simpler forms of Crustacea. Peculiar instincts lead to the choice of a proper habitat, whether a floating body, or a rock, a sponge, a whale, or a turtle ; how admirable, therefore, the harmony between the structure and the instinct ! The voluntary roving animal becomes fixed to some object, and, after various transformations of its organs, the adult state is finally assumed, and the change of form is commensurate with that of its mode of life. The fixed state of the full-grown animal renders several con- ditions necessary to its existence and comfort. Having no power of movement from one place to another, the barnacle is incapable of voluntarily avoiding injury from without. The animals require means of attachment, a shell for })rotcction, and provision for the supply of their wants. All these points have been attended to in their structure, and there is remarkable concurrence of arrangements tending to the well-being of the entire or- ganism. The masterly researches of Mr. Darwin, forming two volumes recently pul)lislied by the Ray Society, have fully elucidated the remarkable modifications of the Crustacean type met with in (he aniiii;ils under discus- 246 SPECIAL MODIFICATIONS sion. Comparison of the following table with that already w crab : — given, will show the relation between a barnacle and a BiNOB. No. 1, 2 & 3, 4, 5& 6, 7 &8, 9, 10, 11, 12, 13, 14, 15, 16, 17, I Appendages. Eyes, ) }■ quite distinct ia early stages. Antennaj, P .^ & Mandibles. Maxillae. Generally coalesce or disappear. Bix pairs of limbs. form three small abdominal segments; the last four are wanting. The appendages of the third ring, or the second pair of antennge, are the primary means of attachment, the union being subsequently consummated by a cementing material, which at first issues from these appendages, and finally also, in some, through special openings in the head. Such then, is the simple means by which the attachment of the barnacle is provided for. In connection with this part of their history, allusion may be made to the habits of a species not uncommon on some of our coasts. In Lepas fascicularis, the cement is very copiously given out, and forms a vesicular ball, which acts as a float. Mr. Darwin states that sometimes several individuals have their stalks imbedded in the same ball, which swims like a cork on the water. As this species grows into a * Fro. 54. Lepas fascicular!!', with its stalk (tosretber with three others, the stalks of ■which ai-e alone seen) imbedJetl In a vesicular ball (constituting a tloat) of their own formation, of which a slice has been cut off to shew the internal structure. Fia. 64.* OF RINGS AND APPENDAGES. 247 "bulky animal, we here see a beautiful and unique con- trivance in the cement formed into a vesicular membra- neous mass, serving as a buoy to float the individuals, which, when young and light, were supported on the small objects to which they originally had been cemented in the usual manner. We have seen a cluster composed of at least a dozen large specimens, any one of which, without the float, would have been sufficient to sink the small quill-feather of a sea-gull to which they were attached. It will be remembered that the posi- tion and production of this singular contrivance depend on modifications relating to certain appendages of the body. As regards means of protection, we may quote Mr. Darwin, who states, "In the mature animal, the whole external covering, whether shell and operculum, or capi- talum and stalk, is formed of the third segment of the head.''* It consists of distinct plates, which overlap each other, and are capable of various movements, in whicii respect it differs from that of all crustaceans, and farther, is never moulted or cast off, as is the case in them. But the animal requires, also, means for procuring food ; this is provided for, in all common barnacles, by a special modification of the thoracic limbs, which form six pairs, and are admirably suited to their intended use. (See Fi(j. 53, h.) Each is two-oared and many-jointed ; " they have a peculiar character, different from the limbs of other crustaceans, not being natatory, ambulatory, nor branchial, but 'captorial,' or fitted for sweeping tht water, and thus catching prey.^f Mr. Hancock describes these appendages as acting like a 2orehensUe net. Is it possible to conceive any better example of parts con- stnicted according to a general model, and yet harmo- • Darwin, loc. clt. vol. II., p. 13. t IbM., vol. II., p. U 248 SPECIAL MODIFICATIONS niously combined and modified in distinct relation to a special purpose, than that found in the harnacle ? As- suredly the lately-developed principle of homology does not set aside, but corroborates the old-established prin- ciple of final cause ; and it appears to us that the more intimate our acquaintance with the one, so much clearer will be our idea and appreciation of the other. Insects — The busy bee, that master architect and builder of its class ; the industrious ants, from some of which man might derive useful lessons in social economy, division of labour, and persevering toil ; the locusts, those rovers and depredators, the Goths and Vandals of the winged articulata ; the painted butterflies, sipping the nectar which Flora provides so bountifully ; the mailed beetles, the athletes of the insect world — notable as swimmers and divers, as sappers and miners, indeed, as adepts in various departments of nature's economy too numerous to be mentioned here ; — all these now invite our attention. The field is so vast that we can only glance at a few cases in which we observe modifications of the archetype, obviously concurring to serve useful ends in the economy of the animal. Whatever difference of opinion may exist in regard to the number of the segments entering into the formation of the body of the perfect insect, the best authorities are agreed that the different pieces are homotypes of each other, and that all modifications and departures less or greater from a common model. We are now to shew that these modifications are intended to serve an end which is more or less obvious. The varied forms of the whole body, in different insects, depend upon the relative development of the parts of each segment and appendage, and the diversities are invariably in direct harmony with the peculiar function to be performed. OF EINQS AND APPENDAGES 249 The reader is doubtless familiar with fhe transforma- tions, greater or less, through which insects pass before reaching maturity. How different is the general ap- pearance of the caterpillar from that of the winged butterfly — the one incapable of flight, and feeding upon the solid parts of vegetables, the other possessed of powerful wings, and having extensive and rajiid means of aerial progression, and feeding on the sweet juices of flowers ! Both possess the same number of true appen- dages for walking, namely, three pairs attached to the segments of the thorax ; those in the caterpillar, or larva, are nearly of the same size and form. But many larv£e, as requiring efficient means of locomotion on a hard sur- face, are furnished with additional limbs, usually called false, because they are not appendages of the archetype, but only prolongations of the external covering of the bodv, and are attached to the abdomen. "Without enter- ing into details respecting the veiy numerous modifica- tions of these false appendages, it may be sufficient to state that whatever their number or form, they are invariably so constructed as to answer every purpose for which they may be wanted in the economy of the animal. It may further be observed that many larva} are des- titute of feet, and yet possess the power of locomotion. And here we see a beautiful compensatory arrangement in the form of minute hooks, which are prolongations of the external covering of the body, the position, number, and forms of which are wonderfully adapted to the pecu- liar habits of the individual. We may conclude this part of the subject by quoting a passage from Mr. New- port:* — "In apodal larvas, endowed with powers of locomo- tion, the ])lace of the true organs of progression is su])])]ied by peculiar developments of the cuticular covering of the • Cyclopjcdla of Anatomy and Physiology, Art. Tnsecta. 11* 250 SPECIAL MODIFICATIONS body, analogous to tlie scales on the bodies of Opliidiam reptiles, and these are employed by the larvae in all their progressive movements in the same manner as the scales on the body of the snake. But in those apodal (footless) larva?, which remain in the same locality until they have passed through all their changes, as the larvae of the bee and wasp, these developments of the cuticular surface do not exist, but the body is perfectly smooth." If such remarkable conformity exists between the habits of the immature animal and the development of certain temporary organs with which it is furnished, we may be prepared to expect harmonious adaptations of the archetype all conducing to the existence and comfort of the perfect insect, suited to its instincts and fitting it to the position which it is to occupy, in earth, air, or water. The usual elongated body of the grovelling larva in general presents evident uniformity in the devel- opment of the segments as well as of the true appen- dages when present, in other words, there is a close approach to the archetype. The new sphere which it is subsequently designed to occupy, demands corresponding modifications in the form of the whole body, and in that of the segments and appendages. In the perfect insect, division of the body into three regions, head, thorax, and abdomen, is generally obvious. Each of these consists of parts adapted to certain ends, and all concurring to the well-being of the entire organ- ism. All of them present entire fitness for their respect- ive functions ; those of the head support certain sensatory organs and appendages for capture, retention, and reduc- tion of tlie food ; those of the thorax afford attachment to wings and limbs ; the abdominal segments protect certain viscera, and serve other purj^oses besides. The differences to be observed in the hardness of the OF RINGS AND APPENDAGES. 251 framework are remarkably adapted to the uses of the part. Where close union and density are wanted for strength, there we find them ; in the head this is specially evident ; mobility is sacrificed for firmness precisely where such is necessary. The consistence of the head segments is, as a general rule, greater than that of any other region of the body. The head is the part of all others most ex- posed during progression, whether in air, earth, or water ; besides, it supports mandibular organs, whose function frequently is to act upon veiy hard materials and fit them for digestion. Owing, in fact, to the close union of the elements of the typical rings forming the liead, there has been more difference of opinion regarding the number of its segments than those of any other part of tlie body. The muscles of the insect are inserted on the internal surface of the framework, and we might naturally ex[)ect a relation between the development of the two. Where strong organs of mastication are needed, the segments of the head are large, being directly proportional to the power which the mandibular apparatus is fitted to exer- cise. Mr. Newport remarks, " wo invariably find that in those insects in wliich the mandibles are large, the whole head is either short and wide, or its posterior portions, to which the muscles of the mandibles are attached, greatly exceed those of the anterior." ■■•'• The great extent of surface occui)ied by the organs of vision in many insects, has an influence also on the gene- ral development of the whole head and of its elements. The rapacious dragon-flies, for example, hunt solely by sight, and their eyes occupy almost two-tliirds of the sur- face of the head, and Ave observe corresponding modifica- tions in the segments. It is unnecessary to enter into minute details regarding the variously modilicd ajjpen- ♦Cyclopudla of Anatomy and Physiology, Art. Iiueata. 252 SPECIAL MODIFICATIONS dages of the different segments of the head ; it will be sufficient to indicate some of the more obvious adapta- tions of the elements to their respective functions. The wide dissemination of insect, life implies considerable rano-e in the instincts and means of existence. The predatory habits of some constitute them the carnivora of their class, and others are not less fitted — than rodent mammals — to gnaw hard vegetable matters. The in- stinct which leads some to sip the sweet fluids of flowers, or stimulates others to tap the integuments of animals or of plants for the purpose of feeding on their juices, equally require adaptation of the mouth to such purposes. But whatever the end to be accomplished, and however great the apparent difference of the organs which mini- ster to the subsistence of the insect, it was long ago demonstrated by Savigny that in every case the parts are fundamentally identical, though varied to suit a purpose. The study of the mouth-organs in insects has occupied the attention of numerous observers, and the results of such researches have shewn how admirably each piece is fitted for its function, and at the same time accommodated to act in harmony with every other. In the great water-beetle (Hydrous piceus) the mandibles are two strong, arched and toothed jaws moving hori- zontally in opposition to each other ; this species is omnivorous. In the truly carnivorous forms, as the brilliantly-coloured and active tiger-beetles, the mandibles are acutely pointed, strongly toothed, and crossing each other like the blades * Fig. 55. Mandible of a large water-beetle, (Hydrous piceus.) There are two such which act in opposition to each other, like the blades of scissors. The opposed edges are hard and toothed. Fig. 55.* OF RINGS AXD APPENDAGES. 253 of scissors, and are thus admirably fitted for dividing the prey. Those of Melolontha (the cockchafer) have short bhint teeth fitted to bruise vegetable matter ; in Cetonia, which feeds on the pollen of plants, the edges of the man- dibles are soft and flexible. The mandibles of the locust are in front so constituted as to form cutting organs, and behind act as grinders of the vegetable food. The maxilhe, or lesser jaws, are organs of prehension and retention chiefly, but may aid also in mastication. Like the organs just de- scribed, they present differences in form and texture in direct consistency with the habits of the insect. Among Hymenoptera, comprehending bees, wasps, &c., the mandibles present very considerable difference in form ; " in the Vespidte, (wasps,) which gather the materials for their nests by rasping off" little packets of fibres from decaying wood, they are broad, triangular, and armed along their edges with strong teeth ; and such is also their structure in Anthidium manicatum, which scrapes off the down from the woolly stems and leaves of plants for the same purpose ; while in the hive-bee, which employs them in moulding the soft wax in the construc- tion of the condjs, they are shaped at the apex like a spoon, without indentations ; tlieir form in each instance being thus distinctly conformable to the habits of the insects."! The highly-developed instincts of bees, which lead to Fio. 56.* •Fig. 50. Maxill r, or sinallcr jaws of the Hydrous. Thoy act in pairs, but as tlioir function Is to hold the food and convey It to the back part if the mouth, they aro not so fiTonn as the inandlhlps, wliidi divide and bruise the food ; they, however, have a geno- ral resembliince In ^hape. t Newport, Cyciopaidla of Anatomy and Physiology, p. 898. 254 SPECIAL MODIFICATIONS the formation of very ingeniously constructed nests, imply the necessity of tools for the work ; these are furnished by the mandibles, while the maxillaa and another cranial . element termed the labium, are principally concerned in collecting the food ; the former are elongated, and with the latter beneath, together constitute a tube by means of which the honey of flowers is conveyed to the mouth. But we must pass on to consider arrangements suitable to the habits of suctorial insects properly so called, and here also, while the general plan is evidently adhered to, the modifications are in strict conformity with the wants of the animal, and all concurring to a common end. Hitherto we have seen that the mandibular appen- dages have occupied either the chief, or at least the pro- minent place in the operation of feeding ; in the Haus- tellate insects (those furnished with a proboscis) the mandibles no longer perform the same important offices, while the maxillge and the labium now assume greater prominence and importance in the economy of the insect. Every one must be familiar with the habits of moths and butterflies " hovering around those opening flowers," and closer inspection would reveal that the insects carry with them an apparatus admirably fitted to reach the sweet juices in parts of the plant, into which the body of the animals could not possibly find access. The short mandibles of the voracious vegetable-feeding caterpillar, though admirably fitted to that stage of life, would be utterly useless in the new sphere which it occupies, when, issuing from the mummy-like case of the pupa, it emerges as a winged imago, endowed with new instincts and new faculties. The perfect insect carries with it an instrument admirably fitted for reaching and drawing up the nectar of flowers. The mandibles are no longer capable of supplying the wants of the animal, as the sweet fluid OF EINGS AKD APPENDAGES. 255 on which it feeds requires no mastication ; hut an organ is needed to suck it up, and of sufficient length to reach the parts of the plant where it ahounds ; such an organ is supplied. It would he difficult to select, in the entire range of the animal kingdom, such a remarkahle example of special modification of typical organs, as that presented to us in the prohoscis of the huttcrfly. The problem is to convert the maxillas (which in some insects we have seen to he organs for prehension and mastica- tion) into organs adapted to the function Ihcy have to perform in the moth or butterfly ; for, as we have just said, the portable flexible tube in these animals really corresponds to the maxilla; of a beetle. Sweet juices abound in flowers, access to the bottom of every floral tube would be impossible to insects having the large prominent eyes of those under discussion, and so a peculiar contriv- ance is necessary under the circumstances — that contriv- ance is simple, yet efficient for every purpose required. The structure of the mouth-ajjparatus in the Lcpidop- tera has been so fully illustrated in other works, that a sunmiary may be sufficient here. The appendages called maxilla> constitute the sucking apparatus. In the words of Mr. Newport, " each maxilla is composed of an immense number of short, transverse, muscular rings. It is convex on its outer surface, but concave on its inner, and the tube is formed by the ap- proximation of the two organs."* But something more is necessary. By what means are the two ojjposcd clian- nels to be kept in sufficiently close contact so as to form a perfect tube ? Reaumur, Kirby, and others, liave de- scribed numerous minute and delicate hooks or teeth, (for tliey assume varied forms in diflerent S]ioci<^s.) wliicli • Newport, loc. cit., p. 00. 256 SPECIAL MODIFICATIONS are arranged in close series along the inner margin of each maxilla, and the teeth of the one set lock between the teeth of the other. The animal is now furnished Fig. 57.* Fio. 58.t with a means of searching every crevice of a flower for the tempting juice which is formed there. But some- thing more is necessary. Not a few Lepidoptera feed upon wing, and the act of feeding is very quickly per- formed ; in the twinkling of an eye the tube is inserted, and the flower is robbed of its sweets. The act of suc- tion, by producing a vacuum, which enables the infant to procure nourishment from the breast, is also brought into play in order that the fluid may rise in the butter- fly's proboscis. . The peculiar air-tubes which traverse the bodies of insects, for the purpose of respiration, are abundantly distributed throughout the maxillcB in the head, and over the gullet and alimentary canal. Experiments made by Mr. Newport led to the conclusion that the * Fio. 57. Head of Noctua libalrix ; in, in.andibles, small ; ma, the two maxillae, large, and forming the proboscis or sucking apparatus. + Fig. 58. A single maxilla of the same. OF RINGS AND APPENDAGES. 257 insect first makes a strong cifort to expel the air, and just when the proboscis comes in contact with the fluid, a powerful inspiratory effort is made, which occasions dila- tation of the tube, producing a vacuum, and thus causing the liquid food to rise. There is still, however, another arrangement necessary in this simple but efficient appa- ratus. It must be long enough to reach to the very bottom of the floral shaft whence the food is to be drav/n, but a long and flexible tube would be liable to injury, and also inconvenient during progression on the ground or in the air ; it must, therefore, be portable ; and here another modification comes in to provide for the comfort of the insect. The two maxillas, conjoined in tlie way we have described, are, when at rest, coiled lilvC the s])ring of a watch, but can be extended with ease and surprising rapidity as required. (See Fig. 58.) The mandibles — which, as we have seen, arc so highly developed in some insects of prey, and are, on the con- traiy, so useless in tlie butterfly — assume a new aspect and function in the blood-sucking Tabanidas. In the typical genus of that family, they are long and lancet- shaped ; and Mr. Newport describes them as acting not from side to side, but with a lioriz(uital movement from Ijehind forwards, cutting also vertically with a sweeping stroke, like the lancets of a cupping instrument. We may add, that the bite of the gnat is efl'ected in the same way. We may now proceed to examine the modifications pre- sented by the next region of the body — the thorax, namely. The three different segments which constitute tliis part will also afford means of illustrating the argument. The first or anterior ring (prothorax) supports the first pair of legs ; the second or middle portion (meso- tliorax) gives attachment to the first pair of Avings and the second pair of legs ; the third or jx^stcrior (meta- 258 SPECIAL MODIFICATIONS thorax) bears the second pair of wmgs and third pair of legs. All these segments and their corresponding ap- pendages present notable differences, according to their relative importance in the same or in different insects. We have now to examine organs concerned principally in that faculty which is so eminently characteristic of the insect tribes. We have seen the very admirable pro- vision made for enabling each to secure its peculiar food ; no less remarkable are the modifications of organs in co-operation for the function of locomotion, so that the necessary food may be sought after. The alar appendages, or wings, are viewed by some as not constituting a necessary part of the archetype, but organs superadded, and serving both for flight and respir- ation.* Their relative development in different species is accompanied with co-ordinate changes in the segments which support them, and the other appendages which form the legs of the insect. Entomologists in treating of this part of the body, cannot avoid alluding to and enlarging upon the evident relation between the habits of the insect and the modifications of the thoracic segments and their ele- ments, and we cannot do better than introduce an abstract of Mr. Newport's remarks.f There is wonderful modifi- cation in shape and variety, in size and position, of the thoracic elements, in order that the body of the insect may be in conformity with its mode of life. In the great water-beetle, (Hydrous piceus,) which burrows deeply in the mud of stagnant waters, and rises also to the surface to bask in the sun, the form of the lower surface of the entire thorax is admirably adapted to its habits. The sternal elements of the meso-thorax and the meta-thorax * The wings may, however, be considered as homologous with the upper append; of Annelida ; — sea-worms are examples, t Cyclopsdia of Anatomy and Physiology, Art. Insecta, p. 917. OF RINGS AND APPENDAGES. 259 are strongly keeled and firmly united together, enabling the insect to float securely. In others nearly allied, but of more active aquatic habits, swimming with ease and quickness, and capable of rai)idly turning and following all the movements of their living prey, there is but a slight keel below, and the edges of the body are sharp, so as to oppose little resistance to the water. In beetles there is alwavs a beautiful relation between the general structure of the thorax and the habits of the insects, whether in walking, flying, or in swimming. In those which pass great part of their lives on the ground, run- ning or walking, the middle and posterior segments of the thorax are often firmly joined together, in order to give greater strength to the whole body. This occurs in all beetles which require great muscular efibrt during flight, and in those accustomed to laborious efforts in tearing, in burrowing, or in running. But, without enlarging on this subject, it may be observed that the size and strength of each segment of the thorax are in direct proportion to that of the append- ages which it supports, and the whole structure of rings and appendages present admirable conformity to the mode of life. For example, when, as in bees, moths, and the common fly, the anterior pair of wings are the chief locomotive organs, the mcso-thorax or middle segment is highly developed, and there is corresponding decrease in tlie other two. Tlie proper appendages of tlic thorax may now bo ex- amined, and in them we find notable correlation between the habits of the insect and the modifications of tlic parts. Here there is a wide field illustrative of the ar- gument ; but since this subject has been already so fully discussed in dlfFcrent treatises on natural theology, it will be unnecessary to do more than refer to a few examples. 260 SPECIAL MODIFICATIONS The legs are the proper organs employed in terrestrial locomotion, and for other purposes besides. As already stated, there are three pairs of such appendages attached to the corresponding segments of the thorax. We have seen that in the vertebrata the limbs or di- verging appendages of certain parts of the model frame- work are variously and suitably modified, according as they are intended for grasping, walking, swimming, or flying. The same law of consistency between form and function prevails among insects, and as in the higher animals, unity and diversit}'- are singularly combined, the same is true among the winged Articulata ; in the words of Professor Kymer Jones — " Nothing is, perhaps, better calculated to excite the admiration of the student of ani- mated nature, than the amazing results obtained by the slightest deviations from a common type of organization. The limbs used in swimming exhibit the same parts, the same number of joints, and almost the same shape, as those employed for creeping, climbing, leaping, and numerous other purposes ; yet how different is the function assigned to them !"* The predatory tiger-beetles are swift of foot — freedom of motion and lightness of the organs are necessary accompaniments, and such is the character of their thoracic appendages ; it is the same in every in- stance where the habits are similar. In those which swim and dive, as the water-beetles, &c., length of lever-power, breadth of surface, and strength of the parts, all are neces- » sary — and such we find to be provided in their limbs. They are not, however, all of equal length, nor do all act equally in aquatic progression. The posterior pair, as regards position and form, are the chief propellers of the insect, they are flat like the end of a paddle, and the ex- tent of surface presented to the water is very much in- * The Animal Kingdom, p. 245. OF KINGS AND APPENDAGES. 261 creased by a fringe of hairs, which do not materially add to the woiglit of the whole hmb. This admirable contrivance servos another purpose, viz., what is called feathering the oar, when a new position is necessary for a fresh impulse ; for in the forward stroke of the limb the hairs are of such nature and so arranged, that they change their position and accomplish the object in ques- tion. Limbs simply intended for walking are usually equally developed in all respects. Surfaces intended to act as sucking discs by the pressure of the air, are by no means uncommon, as in certain water-beetles. In some instances, flat cushions on the limbs, giving out a clammy secretion, are provided in order to enable the animal to climb smooth perpendicular surfaces, or hang with its body lowest from the ceiling ; such is now generally be- lieved to be the arrangement in the house-fly. Mr. New- port remarks, " those insects which support themselves upon the surface of water, as the common gnat, have the under surfoce of each tarsus covered with rows of fine hairs, which repel the water and support the insect upon the surface. If the under part of the tarsi be wetted with spirits of wine, the insect can no longer support itself upon the surface, but immediately sinks down." The powers of the most accomplished vaulter, aided by mechanical adjuncts, arc insignificant in comparison ^vith those possessed by not a few insects. For the accomplishment of such mode of progression, we find cor- responding modifications of the posterior pair of legs, wliicli are chiefly concerned in this kind of function. The large and strong coxa or first piece, is received into a deep depression of the supporting arch ; the piece called thigli is of great length, and very greatly enlarged in transverse diameter, so as to furnish attachment to the powerful internal muscles. The sudden unbending of 262 SPECIAL MODIFICATIONS the strong limb enables the animal to accomplish its purpose. An additional arrangement is alluded to by- entomologists as being provided in such cases ; the lower surface of the tarsus is covered with elastic cushions, which are supposed to assist in the first effort, and finally to act in breaking the fall when the insect alights. The flea, turnip-fly, grasshoppers, &c., present examples of such limbs. In the mole-cricket the fore-limbs are used in tunnel- ling, and admirably suited they are for such purpose, and the corresponding part of the thorax is of commen- surate strength. The basal joint of the limb, called coxa, is of unusual size. The thigh is joined to both coxa and trochanter — an arrangement which adds ma- terially to its strength. The succeeding portion, the tibia or leg, usually so called, is the instrument by which the soil is penetrated and thrust aside ; it is short and broad, the outer surface of it also is furnished with several strong, CD? curved projections, the whole presenting a strong and broad surface, and therefore becoming an efficient instru- ment by which the animal burrows in the sod. In conclusion, it may be observed that the last joint of the foot in insects is usually furnished with a pair of strong hooks, which afi'ord important aid in climbing or clinging to rough surfaces. In a word, whatever the peculiar habit of the insect, the elements of the limb are variously modified to minis- ter to its existence and comfort. We pass on to examine the last part of the body, and m it, the abdomen namely, we shall find modifications of the model not less instructive than those already brought forward. Some difference of opinion exists respecting the exact number of segments entering into the formation of the OF RINGS AND APPENDAGES. 263 third or abdominal region of the insect ; whatever may he the normal number, it is nevertheless admitted that all are homot jjies, and each fitted to its respective function. Generally speaking, the appendicular elements are wanting, or, for the most part, of very secondary import- ance, in the abdomen. This part of the body protects a large proportion of the organs concerned in nutrition and reproduction, and, as the space occupied by these is liable to vary, we generally find considerable capacity of exjiansion in the segments of which it consists, and, in- deed, throughout the whole of this region. But abdominal appendages are not always w^anting, and sometimes they are of the utmost importance in the economy of the insect ; they usually belong to some of the terminal rin2;s. There is an order of insects denomi- nated Hymenoptera, among which we meet with highly developed instincts, leading to the performance of various acts, which could not be accomplished without some cor- responding adaptations in the frame ; all of these are pro- vided and are exactly suited to the instincts and to each other. The saw-fly, the gall-fly, the inchneumon-fly, and others, in the larva condition, feed upon different parts of plants, or on the internal organs of other insects. The female deposits her eggs in suitable localities by means of an instrument, the ovipositor, fitted specially for that purpose. Others are provided with formidable weapons of defence and offence, in the form of a sting. But what- ever be the function of the instruments in question, they arc invarialjly modifications of the same abdominal ele- ments, and in every instance suited to their end. It is among Hymenopterous insects that we find the most jicrfect forms of an egg-depositing instrument ; and as the localities in which the eggs are placed differ, the 264 SPECIAL MODIFICATIONS. modifications of the instruments are of commensurate import. The leaf-flies, the gall-insects, the saw-flies, and ichneumons, all present instruments varying in length and strength, according to the substance which each is intended to penetrate. Those of the leaf and gall-insects are just sufficient to allow them to penetrate vegetable tissues : neither is there any great force requisite to enable the ichneumon female to deposit her ova in the bodies of other insects, or in the cocoons of spiders, or in the eggs of butterflies. The saw-flies, which penetrate hard wood for a similar purpose, are provided with an apparatus of great power and admirable construction. In every special case there is some remarkable harmonious adaptation, so that by inspection of the apparatus we can ascertain the way in which the eggs are deposited. The elements con- cerned in boring are placed in pairs, and furnished with teeth on the edge and sides, the former serving as a saw, the latter as a rasp. This delicate instrument requires support when acting, as well as protection ; and accord- ingly these desiderata are provided, and the sword does not more accurately fit the scabbard than are the respec- tive parts of the ovipositor suited to each other, and to the habits of the insects. Certain elements and appendages of the terminal part of the abdomen are transformed into a saw or file, or both, as the case may be, and others are fitted to give them strength and protection.* It matters not Avhat the size of the insect, whether the comj^aratively large Sirex or the very minute Ichneumon ovulorum,"|" the general plan is the same, but in every instance presents some peculi- arity adapted to the nidus selected by the species. * Lacaze Duthiers, on Genital Armature of Insects, Annales des Sciences Naturelles, 1849, 1852. t This tiny insect deposits several ova in a sinslo egg of a butterfly, the contents of ■wliicb afford sufficient food, as well as protection, to all the young which are produced. OF RINGS AND APPENDAGES. 265 The formidable sting of tlie bee and of the wasp are examples of other modifications presenting no less beau- tiful harmony between organ and function. Generally- speaking, the appendages of the abdominal segments are absent, or if present, very rudimentary, because not re- quired in the economy of the insect. What we have stated respecting the ovipositor and sting, affords proof that when certain appendages are necessary they are provided. "We find them, however, in other cases, furnished for a different puqiose. The insects called skip-tails present remarkable examples of this. In the genus Lcpisma, there is a pair of appendages attached to each abdominal segment. In Podura, and others, the singular tail-like organ consists of an elastic stem ending in two branches, like a fork and its handle. During repose this instrument is bent beneath the insect, and is lodged in a groove ; when suddenly straightened the animal is thus enabled to spring a considerable distance. The handle of this fork- like organ is believed to represent the sternal or lower part of the abdominal segment, the two prongs are stated to be the homologues of the lateral appendages. We may finally, and very briefly, allude to a remark- able transformation of abdominable appendages in another class of the jointed invcrtebrata. The web of the spider is constructed of delicate threads, which are given out by parts called s})innerets ; these are organs consisting of two or more joints. The end of the spinneret is pierced with a great number of small lioles, each of which gives out a dro]) of fluid which liardens in the air. The minute threads of each organ are joined to form one, and those of all the spin- nerets again unite to form llic a])parently simj)k' lliread of the spider, which is therefore in reality complex. There 12 266 MODIFICATIONS OF KINGS AND APPENDAGES. appears to be no doubt that tbe organs which produce the spider's thread are really abdominal appendages, thus singularly modified for the animal's convenience. They are composed of several joints, as limbs are, and in some species one pair of them — not being perforated nor fur- nished with an organ to produce the thread, and there- fore apparently not needed — are nevertheless of interest to the zoologist, as indicating the real nature of the true spinnerets. CHAPTER VIII. R A D I A T A . SECT. I. TYPICAL FORMS OF EADIATA The Radiate type of animal structure, as the name indicates, is characterized by a tendency to repetition of parts round a centre. This division of the animal king- dom comprehends, on the one hand, the minute and soft hydra of our fresh waters, and, on the other, the hard and formidahly-armed urchins of our seas. At one time, many of the radiates were supposed to belong to the vegetable kingdom ; more accurate obser- vation has resolved the doubts respecting their nature, and demonstrated that they belong to the animal king- dom. It may be added liowevcr, that still more recent discoveries have shown that, in the mode of reproduction by buds and ova, they present a remarkable parallelism to plants. And here we see evidence that certain ani- mals and plants have so much of unity of plan, as to shew that they have been constructed by the same Arcliitcct. Our aim is to shew that, while there is adherence to a Radiate jjlan, there are departures from it on the one side and on the other — deviations which have reference to sumt' (md in the economy of the animal. We meet witli difliculfics in this as in other departments, but we 268 TYPICAL FOEMS doubt not that as science advances, and our knowledge of their develoiiment, of their structure, and of their habits, becomes increased, additional proofs will accumulate in favour of our argument. Professor Huxley has done good service in shewing the relations of certain Kadiata, viz., Medus£e, Physo- phorida3, and Diphydte, belonging to the Acalepha, or sea-jellies, and Hydra and Sertulariadee, placed among Hydroid Polyps. He considers them " members of one great group, organized upon one simj^le and uniform plan, and, even in their most complex and aberrant forms, reducible to the same type."* Among Echinodermata,f there is evident adhesion to a common type, while there is, at the same time, wide range in their general aspect. In some of the sea-urchins the body is almost spherical, in the sea-stars it is angular ; but these extremes pass into each other by almost insensible gradations. Among the sea-urchins, Echinocyamus and others present a pentangular outline ; in Asteriscus, one of the sea-stars, the general form is similar, the angles, however, being very indistinct. In Solaster, the angles are more prom- inent ; in Asteracanthion, Ophidiaster, and Luidia, the angles are changed into true rays, and become more and more distinct from the body. In Oj^hiura, this separa- tion into arms and body is complete, and in Euryale, the arms become very much branched. The flattening of the body also differs ; — in Palmi^jes membranaceus, we have a good example of extreme depression, while in some species of Orcaster, the arms are very much dilated, so as to present in section the form of an equilateral tri- angle. Among the sea-urchins we observe similar dif- * Philosophical Transactions, 1S49. + Some hold that the Echinodermata possess annuloso or articulate characters. We here follow the views usually adopted respecting them. OF RADIATA. 269 ferences ; the Echinus Sph^era is remarkably in contrast with the depressed form of the Echinocyamus pnsilhis. The soft and vermiform Holothurias are examples of other snb-typcs of the Echinoderms ; still, a general plan can he traced in all. In star-fishes and urchins, we find copious deposits of calcareous matter in the skin, in the form of distinct plates. M. Gaudry has very fully illustrated the general plan wliich regulates this part of their organization,* He has shewn that the protecting armour in all may he re- ferred to three systems of parts — the endodermic or internal, the dennic or intermediate, and the epidermic or supei-ficial. The internal system is absent in some. The dermic consists of four systems in parts — the amhu- lacral, so called from the locomotive function of the soft appendages which pass through them ; the inter- ambulacrcd, placed between the former series, and adding strength and solidity to the whole framework ; the other two, ovarian, and anal or tergal plates, are respectively connected with the reproductive and digestive systems. The epidermic part of the armour comprehends all those appendages called spines, scales, tubercles, &c., which he shews to be formed after a common plan. There are, moreover, traces of unity, when we examine the minute structure of the plates or of the superficial appendages. The microscope demonstrates that the hard matter consists of branches disposed vertically, and connected together l)y lateral branches, all of which are referable to a typical form. But while the Radiate law generally regulates the external form (and the general arrangement of certain internal organs as well) we find that the number of the radii is also subject to law. However much a sea-star ♦ AnDalcs des Sciences Nnturolles, 1861. 270 TYPICAL iFORMS seems to differ from a sea-urchin, tlie number five pre- vails in both. The question was long ago put by Sir Thomas Browne, " Why, among sea-stars, Nature chiefly delighteth in five points ?" and again, " By the same number (five) doth Nature divide the circle of the sea- star, and in that order and number disposeth those ele- gant semicircles or dental sockets and eggs in the sea hedgehog." " Every plate of the sea-urchin," says Pro- fessor E. Forbes, "is built up of pentagonal particles. The skeletons of the digestive, the aquiferous, and tegu- mentary systems, equally j^resent the quinary arrange- ment, and even the hard framework of the disc of every sucker is regulated by this mystic number. "■'■''' The same writer remarks, " When the parts of Echino- derms deviate from it (five) it is always either in conse- quence of the abortion of certain organs, or it is by a variation hy representation, that is to say, by the assumption of the regnant number of another class. Thus do monstrous star-fishes and sea-urchins often ap- pear quadrate, and have their parts fourfold, assuming the reigning number of Actinodermata, consistent with a law in which I put firm trust, that luhen parallel groups vary numerically hy representation, they vary hy interchange of their respective numhers!' Four is the number which generally prevails in the Acalephs or sea-jellies. In Cyanaea, for example, the stomach is usually subdivided by four ; four oesophageal tubes are continued to their commencement, which is in the form of a quadrate mouth, the angles being prolonged into four tentacles. Sixteen canals radiate from the central cavities.f In the chfirming Cydippe of our own seas, the same * Forbes' British Btar-flshes ; Introduction, t Owen's Lectures on Invertebrata, p. 165. OF RADIATA. 271 quaternary subdivision of the digestive system jirevails. Moreover, the cirri by which it makes progression in the water, are arranged along eight equidistant bands. The Actina? or sea-anemones, not merely have some general resemblance to the well-known flower after which they are named, but we find remarkable order as regards number and relative position of organs, such as we have seen to prevail in plants. M. Hollard has shewn that the concentrical series of tentacula in the sea-anemone are subject to a law of alternation. This is well illustrated in the full- gro^\^l Actinia senilis, the four concentric series of tentacles alternate with each other, and, as regards the numbers in each, the following is the formula : — 10 + 10+20 + 40=80 In some others the typical number is six or a multiple of six. Thus there are twelve tentacula in the first row in Actinia equina, six in Actinia pedunculata, and there are four rows in the first species, and five in the second.f Fig. 69.* SECTION II. ADAPTATION OF RADIATE TYPES TO THE MODE OF LIFE. Amid the general adherence to the Radiate type, we find modifications of parts in reference to locomotion, prehension, and retention of food, protection from external injury, and reproduction, all in evident accordance with the wants of the animals. The Himjile Hydra of our fresh waters, consisting as it • Fio. 59. Plan of 8ca-ancmono, upper surface. Tin) conttr circle rcpresonts the mouth. The smaller circles represent the tentucula In coiiconti Ir ami iiUornaUiig sorics. t Annalcs dcs Sciences Xaturcllcs, 1851. 272 ADAPTATION OF RADIATE TYPES does of little more than stomach, has, in the position, arrangement, and properties of its tentacula, admirable means of securing its prey. Its habits, and the adapta- tions of its organs, have been so often and so fully dis- cussed elsewhere, that we need not dwell on the subject here.* We merely allude to it in the outset on account of its relations to certain others of which it may be re- garded as the type. The little Hydra propagates both by a process of bud- ding and by the formation of ova. The buds sprout out from the body of the parent, and passing through various stages, finally become detached and independent beings, each capable of produc- ing others by the same process. But sometimes this mode of reproduc- tion is so rajiid, that each new Hydra-bud ac- tually has buds of its own before it quits the parent stock. These buds, how- ever, finally drop off and become independent, each forming a fresh colony. The same mode of budding takes place in many others of the Hy- droida, with this dif- ference, that the buds usually remain attached to the stock or parent. Fig. CO.t ♦ See Trembley's Meinoirs; Johnston's British Zoophytes, &c. t Fig. O. IFydra fusca propagating by buds, a, mouth ; &, base or point of attach- ment, a to I), the original animal or stock from which the young or buds are formed; c, point of origin of one of the buds. TO THE MODE OF LIFE. 273 But this building up of a tree-polyp could not proceed to any great extent if all polyps were entirely of the same soft texture as the Hydra. And here comes in a modification to which we owe many of those varied arborescent forms with which the ocean abounds. Long regarded as plants they are now well known to be compound Hydroida. The develop- ment of hard matter on the outside serves as a means of protection and support, in a medium Hable as the sea is to such fluctuations in its condition. The soft material which pervades the centre of the hard covering is just a continuation of the digestive system of the polyps, each of which, protected in its little cell, captures food by means of its tcntacula. The nourishment thus ob- tained contributes to the growth of the united colony, furnishing j^abulum for the formation of new cells and new pol}i)s. But there is another mode of propagation. There is a limit to the increase of the polyp-tree, and necessity for the establishment of new colonies at a dis- tance from the parent. There appear at certain periods in the life of the Zoophyte, cells differing in form and size from those which protect the individual polyps. Fig. 61* • Fro. 01. Catnpannlarla Rclaflnosa. A, frajiinont natural bizo; 15, porlloii onlarRod ; Z", young polyp'-bu. rt, the stock or hod y ; f, a bud, OH lu last figure; c, tentacula of stock; d, youn;^ Medusa, (corresponds to flower-bud In planta,) with its tontocuht and proboscis. Tentacula, c, aro a second growth. 278 ADAPTATION OF RADIATE TYPE of marginal apj^endages. They are provided with a diges- tive system, and organs for capturing prey, and, finally, produce abundance of ova, each of which becoming fixed to a rock or shell forms a polyp stock, and gives origin to similarly modified organisms. Among Echinoderms, as we have already seen, there is remarkable unity amidst great diversity of form and consistence of parts. This diversity in particular cases has an evident relation to the wellbeing of the species. The hard covering of star- fishes constitutes a mailed defence, combining, in most instances, strength and flexibility. The many pieces (thousands) of which it consists in some species, are evidently suited for both the functions mentioned. While the ovarian plates, pierced for the passage of the ova, and the ambulacral, giving exit and support to the dehcate cirri, respectively occupy important relations as regards the economy of the animal. The Comatula, or rosy star of our own seas, presents modifications in conformity with its habits. In its adult condition it can cling to a rock, a sea-weed, or a coral, by means of the simple- jointed arms with which it is pro- vided for that purpose ; while, on the other hand, the large pinnated arms may be used for free progression in * Fio. 66. Advanced state (Medusa) of d. Fig. 65. A, side view ; a, proboscis ; &, lobes, or subdivisions of margin. B, upper view of A, shows quadrilateral mouth in the centra TO THE MODE OF LIFE. 279 the water. In stril^ing contrast with it are the sluggish sea-urchins, whose protecting spines serve both for pro- gression and defence, while the numerous cirri protruded from the openings in the amhulacral plates, acting on the principle of the sucker, enable the animal to anchor itself, or when occasion requires, to move up a perpen- dicular surface. The Holothurias, while preserving the same general radiate type in certain organs, differ in this respect that their body is elongated — approaching the vermiform — and the integuments arc generally soft. They present us with another modification adapting them for a dif- ferent mode of hfe. Now moving by the suckers, which protrude from the pores of the skin, and again by the extension and contraction of their soft bodies, they are fitted for localities inaccessible to their allies, the star- fishes and sea-urchins. CHAPTER IX. NERVOUS, VASCULAR, AND MUSCULAR SYSTEMS. In these systems of parts so essential to the animal economy, we may expect also to find examples of types and special adaptations, and our argument would be incomplete without some reference to the subject. It must not be supposed that the brevity with which we discuss this department is any indication of its inferior importance. More space has been devoted to types and modifications in the internal and external skeleton and appendages, because we believe that the proofs are more easily accessible to the general reader. NERVOUS SYSTEM. The presence of a system of nerves is the most marked character which separates the animal from the vegetable kingdom. In some of the lower forms, its existence has not been clearly demonstrated ; in many it is very rudi- mentary. But as we rise higher in the scale we find an evident advance, commensurate with the endowments of the animal. The simplest function of this system is that of convey- ing an impression sufiicient to excite the contraction of muscular tissue, and thus effect some motion in an organ or its parts. The impression is conveyed by one set of nervous fibres to a centre — a ganglion, and from this it NERVOUS SYSTEM. 281 is communicated to the muscle, which is thus stimulated to contract. This reflex function is not necessarily ac- companied hy sensation, and the movements of the lower forms of animal creation appear to be of the nature just mentioned. But when we take a general view of the animal kingdom, we find other superadded functions dependent on this system ; " it is the instrument of con- sensual and instinctive actions, of mental processes, and of voluntary movements."* In Mollusca, the typical nervous system is usually described as consisting of three sets of nervous centres or ganglia : — 1st, cephalic, supplying the eyes and other parts about the head and mouth ; 2d, pedal, supplying principally the foot ; 3d, parieto-splanchnic, supplying the walls of the body, the heart and gills, &c. (See Fig. 45, parts marked n.) Now, we observe modifications of this type corresponding to the development of the dif- ferent organs, and the necessities of the animal. In dif- ferent mollusca, where the foot is more or less developed, we observe corresponding development of the pedal gang- lion. In the Cephalopoda, or cuttle-fishes, the large organs of vision, the complicated buccal apparatus, and active movements, are aU in relation to the increase of nervous matter, and concentration of its parts. Professor Sharpey has further shewn an interesting modification in the nerves of the arms in evident harmony with the habits of these cuttle-fishes. Each sucking disc (on the arms) is connected by a set of fibres with a ganglionic centre, wliile all the ganglia are at the same time brought into connexion by another fibrous tract with the ceplialic portion of the nervous system. Each sucker can, there- fore — by reflex action — attach itself to any body which ♦ CarpcDtcr'8 Comporatlve Physlolopy. 282 NEKVOUS SYSTEM. touches it, while all are also under the control of the animal. In Articulata, the typical nervous system consists of two nervous cords running parallel to each other, and connected at intervals by dilatations or ganglia in pairs, (See Fig. 67.) The general arrangement is such that every part of the body is furnished with two sets of nervous connexions ; one of these is with the ganglion of its own segment, and another with the cephalic gang- ha. The distribution of the nervous system in Articulata was an obvious relation to the general arrangement of the hard parts, the bod}", as we have seen, being composed of homotypal rings, bearing lateral appendages in pairs. And as we find various modifications of this type in har- mony with some important function, we also find corres- ponding modifications in the nervous system. The late Mr. Newport, to whose investigations we owe so much in connexion with this subject, has shewn that in certain cases there is an enlargement of a portion of the nervous system at certain points, " corresponding to the apparent greater necessity for accumulations of nervous matter at those parts of the cord." This remark is generally ap- plicable as regards the ganglia of the head, the arrange- ment being evidently in direct relation to the functions of the important aj)pendages of that part. There are, farther, certain local modifications, having more special connexion with the appendicular organs. Mr. Newport states, regarding the nerves Avhich supply the mandibles and maxillse, that " union of those nerves at their base is interesting from the circumstance that during mandu- cation a consentaneous movement of the parts is required, since, while the mandibles are employed in chewing, the maxillfe are also employed in turning and assisting to pass the food into the pharynx." NERVOpS SYSTEM. 283 4 - The concentration of the nervous matter in the thorax is evidently a modi^cation of the type in conformity with the presence of wings and legs, the active appendages of that part of the body. ^ The wings require the exercise of great mus- 3 - cular efibrt in order to support the insect ^ " during flight, and the distribution of the ner- vous matter is in ac- cordance with this ne- cessity. But there must also be perfect unison in their action, and this is also provided for, Mr. Newport has de- monstrated that there is a remarkable pecu- liarity in the relations of tlic thoracic ganglia and their connecting fibres, in those insects in which both pairs of fio. gt.* wings arc actively con- cerned in flight. He remarks, " that this is the reason for this curious union of the nerves for the wings, seems ap- parent from the circumstance that it exists in very many tetrapterous insects of rapid or powerful flight, as in the • Fio. 67. Nervous syfltein of pupa of Sphinx ligustri, coiiiposed of two painllol nor- vojis cords, for tlio most part joliiud toyelher side l>y sldo, and coniuctod iuiots of ncr- Tous iiiattur — t'OtiKlloiw. Tin; two larger masses and brandies of nervous iiiiitter, or tlio upper part, Kupply organs in llie licad, a.s eyes, ja%\s, &,c., viz., 1 and '2; tlie two nervous tnftsficx ond branehos auccocding to theao supply the wings and legs, 8 and 4. The re- maining portions arc more uniform. 284 NEKVOUS SYSTEM. Apid« and Iclineumonidas ; while in others, even of the same order, as in Athalia centifolife, which is well known to fly heavily and but a short distance, there is no such combination/' In farther proof of the reason for the modi- fication alluded to, he refers to the Coleoptera, in which the anterior pair of wings is modified to protect the pos- terior during repose. These anterior wings are merely elevated, and nearly motionless during flight. Now, in these insects " the nerves are derived separately from the cord, and proceed to their destination without being first combined in a flexus."* As regards Articulata generally, the modifications of the typical nervous system are admitted to be in consis- tency with the functions of the organs to be supplied. The larger nerves supply the organs of the senses, those of secondary size go to the voluntary muscles, and the smallest are for organs concerned in automatic motions. In the organs of the senses, the size of the nerves appears to be in inverse proportion to the density of the agent, so the eyes receive the largest. The size is also in direct proportion to the complex nature of homologous organs in diflierent species.f The remarks of Dr. Carpenter are so much to the point in reference to this part of our subject, that we cannot do better than sum up in his words : — " In Inver- tebrata, the nervous system consist of a series of isolated ganglia, connected together by fibrous trunks. The number of these ganglia, and the variety of their func- tion, depend upon the number and variety of the organs to be supplied. In the lowest Mollusca, the regulation of the ingress and egress of water seems almost the only function to be performed ; and here we have but a single * Cyclopaedia of Anatomy, Art. Insecta. + Straus Durckheim, Comparative Anatomy of Articulata. NERVOUS SYSTEM. 285 ganglion. In the star-fisli we have five or more gan- glia ; hut they are all repetitions one of another, and arc ohviouslv the centres of action to the several segments to which they respectively belong, neither having a pre- dominance over the rest. And in the higher MoUusca, and in Articulata, we have • a ganglion, or more com- monly a pair of ganglia, situated at the anterior extremity of the body, connected with the organs of special sensa- tion, and evidently exerting a dominant influence over the rest. In the lower Mollusca, we have but a single ganglion for general locomotion ; but this is doubled laterally and repeated longitudinally in the Articulata, in accordance with the multi2)lication of their locomotive organs, so as to form the ventral cord. In like manner, the Mollusca possess a single ganglionic centre for the respiratory movements ; and this is repeated in every segment of the Articulata, forming a chain of respiratory ganglia, which regulates the action of the extensively- diffused respiratory apparatus of these animals. The acts of mastication and deglutition, again, in both sub- kingdoms, are immediately dependent upon a distinct set of ganglionic centres, which are cormected, however, like the preceding, with the cephalic ganglia. And wherever special organs are developed, whose operations dej)end on muscular contraction, ganglionic centres are developed in immediate relation with them ; so as to enable them to act by their simple reflex power, as well as under the di- rection of the cephalic ganglia, as in the case of the suckers of the cuttle-fish." '•'•■ From what has been stated, we see evidences of a common jjlan, with numerous special modifications neces- sary to some end in llie animal economy. In Vertebrate animals, wc llnd ;i very obvious correspondence between • MoiJiial of Physiology, p. 028. 286 NERVOUS SYSTEM. the arrangement of the bony framework and the distri- hution of the nervous centres ; skull and spinal column are respectively constructed to give them support and protection. In viewing the entire animal kingdom, we find that we cannot compare the whok of the well-developed ner- vous system in the higher forms with that of the lower ; still Ave find, in the nervous system of the Vertebrata, certain parts which are homologous with the whole of that of Invertebrata. In the higher Articulata, the cephalic ganglia are considered homologous with a series of ganglia forming a most important part of the brain- mass in Vertebrata, and having relation to certain organs of sense, as the eye, &c. The abdominal nervous cord in Insects, &c., is homologous with the spinal cord of Vertebrata, the essential difference being greater con- densation of parts in the latter than in the former. The superadded portions in the nervous system of Vertebrata have an evident respect to the superior endowments of the animal. Cerebellum and cerebral hemispheres have no distinct representatives among the Invertebrata series. On comparing the very lowest of the Vertebrata with the highest, we find evident difference in the relative development of the most characteristic parts of their cerebral system. The lowest forms of fishes have the hemispheres of the brain in a very rudimentary condi- tion, while in man they attain their highest development. " The size of the Cerebral Hemispheres holds a close relation with the increase of the Intelligence, and with the predominance of the Will over the involuntary im- pulses. The increased size of the cerebellum, on the other hand, seems connected with the necessity which exists for the adjustment and combination of the loco- motive powers, when the variety in the movements per- NERVOUS SYSTEM. 287 formed by the animal is great, and a more perfect har- mony is required among them."* Such being the functions of brain and cerebeHum, we may expect to find modifications consistent with the ne- cessities of the animal, "jrhe size of the cerebellum dif- fers very much in the class of fishes ; but its development appears generally to be in direct proportion to the active powers of the animal. " Thus it is very small in the lazy lump-fish, and extremely large in the active and warm- blooded Tunny."t In the Lampreys, whose mouth acts on the principle of the sucker, so that they can attach themselves to their prey and devour it at leisure, we find that the cerebellum is relatively small. Whereas, in the active and predacious sharks, it is of great size ; these Felidse of the ocean have no swim-bladder, and their mouths being placed transversely beneath the snout, they require peculiar and active movements of the whole body for securing and overcoming the struggles of the resisting prey. This conformity of the development of tlie cere- bellum to the peculiar habit of the animal is equally illustrated in the class of Reptiles. Their habits are generally inert, and the cerebellum is proportionately small. The very reverse is true of birds — characterized by the variety and power of their muscular movements. We have already seen that in Articulata there are local adaptations of the nervous system, co-ordinate with the functions of the parts supplied by it. In the homo- logous part — the spinal cord — of the vcrtebrata, we find similar harmony. In certain reptiles we find this corre- lation very obvious. In the serpent the absence of limbs is accompanied with a remarkable unif)rmity of the spinal cord and the nerves given oft' i'roiu it. On the other • Carpenter's Manual of Physiology, p. 530. 1 Owen's Lectures on Comparative Anatomy, vol. II., p. ITC. 288 VASCULAK SYSTEM. hand, in the frog, whose hind limbs are highly developed and of great comparative muscular power, we find cor- responding enlargement of lower part of the nervous cord. Two enlargements occur in the spinal cord of birds, one corresponds to the wings, the other to the legs. As might be expected, these enlargements generally present differences of relative size, corresponding to the different relative development and powers of the anterior and posterior extremities. The posterior enlargement is greater than the anterior in the Struthious birds (ostrich, &c.) in which the whole function of progression is effected by the posterior extremities. In contrast with this, we observe that in birds of powerful flight, the greatest en- largement of the nervous matter corresponds to the posi- tion of the wings. VASCTILAR SYSTEM. Our remarks under this head will be confined to the highest animals, viz., mammals and birds. In them we find a highly developed system of vessels for distributing the products of digestion, removing certain materials derived from the waste of the animal frame, and supply- ing the system with oxygen gas. These two latter func- tions are in intimate relation to a surface or organ for respiration. The central organ of circulation — the heart — presents the same structure in mammals and birds, and, generally spealdng, the blood-vessels are distributed according to a plan which is common to both. Of the four cavities of which the heart consists, two are set apart for the purpose — the one receives, the other propels — of trans- mitting the dark-coloured or venous blood to the lungs, tor the purpose of respiration. Such are the functions of the cavities on the right VASCULAK SYSTEM 289 side, constituting the respiratory heart. Of the two on the left side, one receives and the other propels the Wood — arterial — which has been oxygenated in the lungs. We have already pointed out the harmony between the development and distribution of nervous matter, and the necessity for variety and force of muscular effort. But nerves and muscles cannot perform their respective functions without a sui:)ply of oxygen. Now such co-ordi- nation of parts is clearly illustrated by some peculiarities in the arterial system of birds. The large muscles called pectoral, (from their position on the breast) which are chiefly concerned in the movements of the wings, are supplied by arteries of great magnitude, " which, instead of being inconsiderable branches of the axillary artery, are the continuations of the trunk of the subclavian, of which the humeral is only a branch.""'-' Another adaptation in the arterial system of birds we shall allude to in the words of Dr. Carpenter: — "In most Mammalia, as in Man, the right anterior extremity is more directly supplied with blood from the aorta than the left ; so that the superior strength and activity of this limb would seem to be not altogether the result of habit and education, as some have supposed. In birds, however, where any inequality in the powers of the two wings would have prevented the necessary regularity in the actions of flight, the aorta gives off its branches to the two sides with perfect equality.''^ Among the mammalia, also, we find singular departures from type in order to accomplish a special end. We have already alluded to the habits of the sloth, and the remarkable i)rovisions in the structure of the skeleton. The distribution of the vessels in its fore and liiiid limbs • Cyclopu'dla of Anatomy, Art. Atex, p. 334. t I'rlnclpU-H of Comjiurutlvo Pliyaiology, p. 204. 290 VASCULAR SYSTEM. is admitted to be a modification of the general pljin suited to the habits of the animal. The arteries which supply the fore and hind limbs are subdivided into a number of branches, of nearly equal size, which commu- nicate laterally with each other, and are exclusively dis- tributed to the muscles. Those which supply the bones and other parts, present no such j^eculiarity. The effect of such distribution of the arteries will be to diminish the velocity with which the blood flows to the parts. The peculiar arrangement is admitted to have a relation to the slow movements of the animals, though it may not be easy to say " whether such slow movements of the blood sent to the muscles be a subordinate convenience to other primary causes of their slow contraction, or whether it be itself the immediate or principal cause,"* The celebrated John Hunter long ago pointed out a remarkable distribution of the vascular system in the whales, an evident provision in conformity with their power of diving and remaining for a time under water. Their arterial system is characterized by extensive net- works of vessels, chiefly distributed over the walls of the chest. "It is to be presumed that this singular compli- cation of vessels is caused by the necessity in which the Cetacea are often placed of suspending their respiration, and consequently the oxygenation of their blood during a considerable time. These numerous arteries form, therefore, a reservoir of oxygenated blood, which, re- entering the circulation, supports life throughout, where venous blood would only produce death."f We may now briefly allude to adajjtations in the ves- sels which carry dark-coloured or venous blood. The typical venous system of the mammalia, according to * Cyclopaadia of Anatomy, Art. Edentata. ■f Cyclopjedia of Anatoiny, Art. Cetacea. RESPIRATORY SYSTEM. 291 Rathke, consists of four lateral primitive trunks. We have jnst stated a peculiarity in the arterial system of the -whales ; the same animals present also a special modification of the venous system in evident adaptation to their habits. The extensive net-works of veins in the interior of the chest and abdomen, serve as reservoirs of blood hio-hlv charu-ed with carbonic acid, the accumula- tion of which in the right side of the heart would occasion death. The suspension of respiration during the act of diving, renders such co-ordination of parts absolutely necessary. As connected with this subject, we may allude to a peculiarity of the veins of the bat's wing, described by Professor Jones. The wall of these vessels are endowed with a power of rhythmical contraction and dilatation, which, in the natural state, is continually going on at the rate of seven to thirteen in a minute. This contractile power, " supported by the presence of valves, is called forth to promote the flow of blood in the wings, which, on account of their extent, are, as regards their circula- tion, in a considerable degree, though not entirely, be- yond the sphere of the heart's influence."* RESriKATORY SYSTEM. We shall only briefly refer to type and modifications in this department. Allusion has already been made to the necessity for oxygenation of the blood, and the re- moval of the carbonic acid which accumulates in it dur- ing its course through the system. In the warm-blooded animals, whose temperature is generally higher than that of the medium, air or water, which surrounds them, there is another requisite, viz., the power of kee])iiig up such temperature by the combination of oxygen wilh materials • rhllosophlcal Transactions, Turt I., 1862. 292 KESPIRATORY SYSTEM. supplied by the food, a process which is really a kind of combustion. In many of the lower animals there are no special or- gans for respiration, the fluids of the tissues being suffi- ciently aerated through the medium of their own walls, or of the general external covering of the body. When, however, special organs for respiration are provided, they are admitted to be all mere modifications of one plan, viz., a portion of the surface of the body of more delicate texture than the rest, and j)ermitting the atmospheric air to pervade the parts, and come in contact with the nu- merous vessels with which the organ is provided. Such is the common plan on which both lungs for aerial and gills for aquatic respiration are constructed. Hitherto, in treating of types and modifications, we have spoken of homological organs ; but in examining the respiratoiy system, we have to do with some which are analogous, but not necessarily homologous, that is to say, similar in their function, but frequently different in their nature. Nevertheless, it appears that in this view also there are arrangements bearing on our subject. Generally speaking, gills and lungs are respectively in singular conformity with the different media inhabited by the animals. Gills are usually extensions of some part or other of the external surface of the body, and being necessarily in contact with the water which yields the air requisite for the performance of the function of respiration, complex arrangements of organs are less re- quisite, more especially since the general smface of the body takes a part likewise in the act of respiration. In reptiles,* in birds, and mammals, the respiratory surface is internal, and the whole apparatus is more complicated, * Certain reptiles begin life with gills, and some, even when mature, have both gills and lungs. RESPIRATORY SYSTEM. 293 and there are adaptations of various organs for perform- ing the acts of inspiration and expiration. We have said that respiratory organs arc not neces- sarily homologous, and in connexion with this, we find a remarkable instance of departure from a plan, in accord- ance with the necessities of the animal. The gills of fishes are not of the same nature as the lungs of other Vertebrata, still the latter organs have their homologues in the fish, but they assume a new function, and one which is admi- rably suited to the wants of the animal. The sound-blad- der, swim-bladder, or air-bladder (for it has all these names) by which certain fishes can regulate their depth in the water, is a rudimentary lung turned to a new purpose. Finally, whatever be the modification of the respira- tory system, there is general adaptation to the nature of the medium and the wellbeing of the animal. The gills of fishes require no powerful efibrts to bring fresh sup- plies of water, and thus there is room for greater expen- diture of muscular force in swift progression through the medium they inliabit. Internal extension of respiratory surface, well protected from external injury, is just such a provision as is most conducive to the comfort of the mammal. The whale, living in water, yet breathing by lungs, has arrangements, in the form of its tail and in the position of its nostrils, which enable it to rise to the surface with case, and get fresh supplies of necessary air. The wide diffusion of air from the lungs through the soft parts and bones of the bird, all directly co-operate to facilitate ascent in the air, by diminishing the relative weight of the body. In Articulata, we find homologous parts concerned in respiration, but acting through different media. In some of the lower aquatic forms, tlu! water- vascuhir system is homologous with the branched vessels of insects, which 294 MUSCULAR SYSTEM. are adapted for aerial respiration. In both instances the arrangement is suited to the necessities of the indi- viduals ; the extensive distribution of the air-vessels in the perfect insect being in correspondence with the power of flying, by reason of the diminished specific gravity of the animal consequent on the very free access which the air has been to every part. MUSCULAR SYSTEM. In this as in other departments, there is still much to be accomplished as to our knowledge of a plan, and of modi- fications. The few observations which we have to offer will be confined to vertebrate animals. The general arrangement of the muscular system corresponds very much to the form of the skeleton. The greater or less flexibility of the vertebral column, the size of the hmbs, the mode of progression, whether in water, in the air, or on the ground, all imply greater or less peculiarities of this system. The idea of general correspondence with a type is clearly indicated by the nomenclature adopted in describing the muscles of at least the three higher classes of Vertebrata, viz., mammals, birds, and reptiles. The following are some of the principal groups admitted by anatomists : — muscles of the shin, of the spine and head, of ribs, and walls of abdomen and cliest, of limbs, of the lower Jaw, of voice, eye, &c. Intimately connected with the skin, and lying beneath it there is a layer of muscular fibre in all Vertebrata — with the exception of certain rejDtiles where it is unneces- sary, owing to the development of hard matter in the skin, and its consequent inflexibility. At difierent parts of the body in the same animal, we find local modifications evidently suited to some peculiar end in the economy. Such tegumentary muscles are in- MUSCULAR SYSTEM. 295 tended to act either on the skin itself, or on some of the appendages which arise from it. Among fishes, tegumentary muscles a])pear in connec- tion with the dorsal and other fins, which can be thus elevated or depressed according to necessity, either for defence or offence, or as balances or partial aids in aquatic progression. In the class of birds, the muscles of the integument frequently attain a high degTce of development. In the Af)teryx of New Zealand they are of great strength — a provision of the utmost importance, because its habits expose it to accumulation of soil about its feathers, which must be shaken with some force in order to dislodge it. But there are bundles of small muscles connected with the quill portion of the feathers. In some of the web- footed species each feather has four or five small muscles specially intended to move it in different directions. In the Gannet it has been calculated that there are about 3000 feathers jjrovided with such muscles, the total num- ber of which will therefore not fall short of 10,000 or 12,000. It is by means of such skin-muscles that the cockatoo elevates or dei)resses its crest, and the turkey- cock bristles up his feathers. There are numerous oc- casions on which these and other special arrangements of the cutaneous muscles are needful in the economy of the bird, and essential to its comfort. The peculiar shield-like scales on the belly of serpents are jmt in motion by muscles which belong to the cu- taneous system, and are thus fitted to aid in ])rogres- bion over a rough surface. Ill Mummulia, we find greater or less modification of the same system in conformity with the hal)its of the aninml. The quills of the ])orcupinc and of the hedgc- h(jg are set in motion by similar cutaneous muscles, and the latter animal presents an additional arrany soft skeleton, the sharks rank much tl\e higher — they are, in fact, the highest of their class ; the higlily developed brain, their organs of sense, &c., prove them to liold the rank w(! have stated, tlic Lmijucys and ♦ Murchlson's Slluria, p. 239. 320 TEACES OF PLAN liags being far lower in type. The unequal development of the tail (heterocercal) in the full-grown shark is the only remaining argument in favour of their being per- manent representatives of an embryonic state, and, there- fore, low in type. But this also must fall to the ground us an argument, because founded on an erroneous or mistaken view of the case ; for the symmetrical develop- ment of the tail actually precedes the unsymmetrical, in certain fishes. The observations of M. Vo2:t, in reference to this matter, has been either misunderstood or misre- presented. The young Coregonus, (one of the salmon family,) on which his investigations were made, has actually at the first rays of the tail-fin arranged sym- metrically above and below the end of the spinal column, and therefore homocercal ; the unequal development of the tail-fin (heterocercal) is the final condition, as, in- deed, it is in the Salmonidfe, contrary to the usual opinion.* The earliest fishes known to us were not the lowest of their class, but actually am^ong the highest. Evidence of a similar tendency is derived from a con- sideration of some of the earlier invertebrata. One of the most ancient Crustacea yet discovered, Hymenocaris vermicauda, found in the Bangor slate, is not of low type, it is among the highest of the Phyllopod order, which is not very far removed in structure from the very highest of the Crustacean class. It is not true, as has been affirmed, that man and the higher animals, in their dif- ferent stages of embryonic life, represent some permanent forms of organisms lower in tlie scale ; nor can any proof be adduced of an analogous progress in the womb of time. Even if it were strictly true that there was a gra- dual improvement in type as time rolled on, it would * For additional remarks on tliis subject, we would refer to a Lecture by Professor Huxley at the Royal Institution, April 1855. Annals Nat. History, July 1855. IN FOSSIL REMAINS. 321 still be necessary that those who adopt the "development h}T30thesis," should prove that transmutation of a low into a high grade had heen accomplished. Allowing that the first position had been established, the question remains, whether this might not have been the plan of the Creator in bringing forward the beings which Uve on our earth. The supporters of the idea of progressive development and transmutation of species in a long series of ages, be- lieve also in a progression of life from sea to land, and that this explains what they denominate " the barrenness of Creation ;" that is to say, that certain conditions of the earth's surface, favourable to the support of animals, long preceded their appearance, inasmuch as time was required for the necessary transformations of marine animals into others fitted to live upon the land. It may be true that uninhabited dry land existed at periods when the sea was the abode of many invertebrata, and so may have continued for a time previous to the appearance of ter- restrial beings. But all this does not prove transforma- tion of one animal into another, nor the progression of life from sea to land. It remains to be proved — and the onus probandi lies with those who make the assertion — that marine animals can, by any force of circumstances, or in any course of time, however long, become converted into beings fitted to a new sphere of life on land. If certain terrestrial conditions have preceded the ap- pearance of animals suited to them, we have in all this a manifestation of the foresight and beneficence of the Author of all, and proof of a method which pervades all creation. The bird constructs its nest before the callow broud ap])ears ; the bee lays in a store of food when the flowers yield their sweet juices in abundance, and long before winter arrives ; an internal instinct leads to innu- 14* 322 TRACES OF PLAN merable acts on the part of animals for the preservation of their own hves, and for their young. In a word, there are acts of anticipation flowing from instinct, which have a special relation to some important end as yet in the womb of time. And when we attribute foresight and work of anticipation to Him " who knows the end from the beginning," we do not consider such as derogating from the infinitude of the wisdom of the Great Creator. We find so many remarkable relations between the physical condition of our earth and the wellbeing of its races, that we cannot avoid seeing in the historical evi- dence of geology some traces of order, a winter, a spring, the seed-time, and a harvest of creation ; a winter Avhen life was absent ; a spring when preparation for it was accomplished, and an era when it was called into being ; and so sucessively to the time when the highest created intelhgence of our earth w^as brought forward to take pos- session and occupy the earth now prepared for him. As taking this view, we tliink that the argument in favour of progressive development and transmutation of species, founded on the pre-existence of conditions fitted for or- ganic Hfe — before that life appeared — is of no value. The late Professor E. Forbes, by whose researches geology has been so much enriched, has propounded an ingenious theory on this subject.* In order to charac- terize it he uses the term, " Polarity in Time," as expres- sive of a law which corresponds to the primitive plan of the Divine creation, but which, as being Divine, is completely independent of the notion of time, although only com- prehensible by us in relation to time. The different geological epochs he comprehends under two heads, the Palasozoic, or most ancient, and the more modern, styled Neozoic. On comparing these he finds that " the mani- * Royal Institution, Evening Meeting, April 28, 1854. IN FOSSIL REMAINS. 323 festations of generic types during each exhibit striking and contrasting phenomena. The maximum development of generic types during the Paleozoic period was during its earlier epochs ; that during the Neozoic period towards its later epochs." The following tahle renders the meaning more evi- dent : — Neozoic period, Palaeozoic period. T, .. ji _.• 1 /Epoch of maximum develop- Present and tertiary epochs, ( ^ '■ Cretaceous epochs, ' of Neozoic generic I Oolitic epochs, . . I Triassic epochs, . . Permian cpoclis, . Carboniferous epochs, Devonian epochs, . Silurian epochs, . . ment ( types. Intermediate. j EpocJis of poverty of j)i'oduction { of (jeneric typea in time. Intermediate. {Epoch of maximum develop- ment of Palseozoic generic types. But besides the concentration of a maximum of gene- ric types toward the earlier stages of one and the later of the other great period, he thinks also there is a sub- stitution of group for group during the contrasting epochs, as shewn by the following comparison : — Neozoic. Cycloid and Ctenoid fishes. Malacostracous Crustacea. Dibranchiate Cephalopoda. Lamellibranchiate Acephala. Ecliinoidea. Six-starred Corals. Paleozoic. Ganoid and Placoid fishes. Entomostracous Crustacea. Tetrabranchiato Cephalopoda. Palliobranchiate Acephala. Crinoidea. Four-starred Corals. Some objections have been made to the general classi- fication of geological epochs adopted by the author of Wliere experienced and j'l'ofessed geolo- these views,* • Th"' objections refer to tlifi position of the Pcrinhin ami Tiiassln ppoclis In Un' tnbiilBr view, and \.\\<: propriety of comporliig the primary period with the Jurusslc, Chalk, uiid Terllory formations. 324 TRACES OF PLAN gists are at issue, it would be presumption in us to oflfer any dogmatic decision ; but we cannot help thinking that an obvious objection applies here — and indeed, more or less to every theory — it seems to be taken for granted that we have almost, if not altogether, attained a suffi- ciently comj)lete knowledge of extinct forms. This is surely far from being the case, and the lamented author of the theory of Polarity had himself, in his comparatively brief career, contributed so largely to our records of extinct beings, that there is room for expectation that very much still remains to be done, and that more information must flow in as time rolls on. But we pass on to another opinion, which seems, upon the whole, very consistent with facts hitherto revealed by the observations of palaeontologists. As there is a certain law of progress in the develop- ment of the young animal to the day of its birth, so there seem to be some traces of parallelism to this in the order of creation — a progress in uterine life, and a parallel march in the womb of time, from the beginning of the Creation to the day when man was ushered into existence. In the development of the animal. Von Baer has shewn that " the more special type is developed from the more general." There seem to be proofs of similar progress in time. The subject has been very fully illustrated by Professor Owen in his various writings. He remarks, "As we ad- vance in our survey of the organization and metamor- phoses of animals, we shall meet with many examples in which the embryonic forms and conditions of struc- ture of existing species have, at former periods, been persistent and common, and represented by mature and procreative species, sometimes upon a gigantic scale."* * Lectures on the Invertebrata, IN FOSSIL REMAINS. 325 The common crab, in the different periods of its life, re- presents conditions which resemble those met with in the Crustacea of succeeding geological epochs. 2. Macrourous. (Tail long,) . . j . DEVELOPMENT OF THE COMMON CRAB. EXTINCT CRUSTACEA. 1. Entomostracous, .... Trilobites of the Palaeozoic age. Crustacea of the Oolite formar tiOD. 3. Anomourous. (Tail moderately de- ( Crustacea of the Chalk forma- veloped, and of soft consistence,) ' tion. 4. Brachyourous, the adult condition. \ (Tail short, and turned in beneath > Crustacea of the Tertiary epoch, the thorax,) ) Other examples might be cited ; the above is suffi- cient for our purpose. It must, however, be specially observed, that " no extinct species could be reproduced by arresting the development of any kno^vn existing species of Crustacea ; and every species of every period was created most j^erfect in relation to the circumstances and sphere in wliich it was destined to exist."* But extinct forms are not always the representatives merely of the earlier stages of higher forms in the earlier periods of creation. We find another principle illus- trated : in some instances it is very evident that the earlier forms " present in comhination those characters which are found to be separately distributed, and more distinctly manifested among groups that have subse- (piently made their appearance."f A remarkable extinct order of Echinodermata has been very fully examined and described by the late Professor E. Forbes — the Cystidea : it illustrates the p(jiiit alluded tu. • Owon'B Lcofnrps OD Invortcbrata. t C'ari»cntcr'» I^rliidplcs of Coiiiparatlvo I'liyslology, p. 112, 4th i.liHoii. In this ad- uilrablo work the reader will fliid a very luold demonstration of the subject 326 TRACES OF PLAN PaL/Eozoic. Recent. Order Cj-stidea. A stem, and intes- ) Order Crinoidea. A stem, and in- tine with two openings. I testine with two openings. Order Cystidea. Certain species have } Order Ophiurida. Rays or arms arms like those of Ophiurida. ) snake-like, spines for locomotion. Order Cystidea. In certain genera ) Order Asteriada. Body lobed, that the body is lobed. ) is, angular or rayed. Order Cystidea. Body enclosed in (^ Order Echinida. Spherical or de- a shell of polygonal plates. ) pressed shell, of polygonal plates. Order Cystidea. Ovarian opening ) Order Holothuriada. Ovarian open- single. . ' ing single. From the above comparison, it will be seen that the single extinct order Cystidea comprehended in itself characters which are, so to speak, divided among five orders at the present day. We have here, therefore, a very notable instance of a progress from the more general character to the more special in the lapse of time — for the orders in the right hand column were very partially represented in earlier epochs, and some of them did not exist at all. Other illustrations might be brought forward among Vertebrata ; we shall only allude to one, as regards dentition. Professor Owen remarks that the typical character of the dentition teas more closely and generally adhered to in genera than existed during the oldest tertiary epochs in geology, than in their actual successors. The earlier forms of mammals, whether herbivorous or carnivorous, very generally pre- sented the typical number of teeth, (p. 215,) whereas, in the present day, such dental character is the exception and not the rule. It would be presumptuous in any one, at the present stage of science, to suppose that he had been able adequately to ajDprehend the plan in the Divine mind ; but these facts seem to show that there has been an IN FOSSIL REMAINS. 327 advancing series of some kind, proceeding all tlie while on a uniibrm plan. III. Prophetic Plan. — We are next to inquire whether the earlier books of the stone-volume present any records of organic forms, which point to higher forms to come forth in later epoch's ; Avhether it discloses any foreshadowing of beings that were to follow ; and espe- cially of man, the consummation of all. The nature of the divine and creative act by which the earliest of earth's creatures were summoned into being- must ever remain unknown to us. But it is allowable to examine the asj)ect of these early organisms, and inquire into the relations which they bear to the succeeding series of animated beings. Our position in time, and the van- tage ground on which natural science enables us to take our stand, admit of our drawing an instructive comparison between the forms of the Fauna in earlier epochs, and those that appeared in later times. We confine our at- tention, in what follows, to the Vertebrate type. Siluria, rendered notable by the resistance of Carac- tacus to the invaders of his country, is as famous in geo- logy, as its former people are in tlie history of ancient Britain. In its rocks are a succession of strata which reveals to us what seems the dawn of creation in our world. Its signatures appear to be the most ancient re- cords of organic life. Those beautiful organisms, the Graptolites, are not found in any pakeozoic rock younger tlmn the Silurian ;■••" and only one — the Graptolites prio- don — is plentiful in the upper divisions of that system, Grap. Flemingii of the Wenlock rock being rare.f We have, therefore, a mark by whicli to determine the re- lative age of tlie ui)])er Ludlow bone-bed, in which the » Murchlnou's SUurla, p. 4T. Ibid., p. 208. 328 TRACES OF PLAN" earliest vertebrate remains occur. There is clear evidence that they belonged to fishes, and, consequently, animals formed after the vertebrate model. This is enough ; here we find at a very early period, a plan of structure which has appeared under various modifications in every subsequent era. Those few species of the 'upper Silurian period were but the herald to indicate the subsequent advent of those of the old red sandstone, remarkable not only for their numbers, and their singularly bizarre forms, but some of them especially interesting in relation to this head of our subject. The highest authorities are agreed as to their general place in the class of fishes, and the names of Agassiz, of Professor Fleming, of Mr. Hugh Miller, and others, must ever remain associated with the elucidation of the history of these singular beings. As the Onchus of the Ludlow rock announced, as it were, the dawn of vertebrate life, and foreshadowed also others of its own class that were to follow, so the Holopty- chus, and others of the old red sandstone, in turn pointed forwards to the Reptilian class. The term Sauroid (lizard- like) has been applied to many extinct, and a few living forms, in order to indicate their relationship to the reptiles. The still existing Lepidosteus of America, and Polypterus of the Nile and of Senegal, present a combin- ation of characters eminently developed in not a few of those found in the rocks of the Devonian epoch, (Old Red Sandstone.) We can here take shelter under the high authority of Agassiz, who remarks, " In Lepidosteus the articulation of the vertebrte differs from that of the verte- br£e of all other fishes, no less than the structure of their scales. The extremities, especially the pectoral limbs, assume a higher development than in fishes generally. The jaws, also, and the structure of the teeth, are IN FOSSIL REMAINS. 329 equally peculiar. Hence it is plain that before the class of reptiles was introduced upon our globe, the fishes being then the only representatives of the tj^e of verte- brata, were invested with the character of a higher order, embodying, as it were, a prospective view of a higher de- velopment in another class, whicli was introduced as a distinct type only at a later period ; and from that time the reptilian character which had been so permanent in the oldest fishes was gradually reduced, till in more re- cent periods, and in the present creation, the fishes lost all their herpetological relationship, and were at last en- dowed Avith characters which contrast as much with those of Reptiles as they agreed closely in the beginning."* In a few existing forms, (Lepidosteus of America, and Poh^terus of the Nile,) and in all primeval fishes, the pelvis and posterior limbs retained their position in con- nexion with the point of junction of trunk and tail, a character indicating superiority of type. This does not apply to the fishes of subsequent epochs, for, from the period of the chalk formation down to our own day, a large proportion of them have the ventral or hind fins re- moved from the tj^ical position and placed far forwards, near the head. Such position of posterior limbs in the very dawn of ver- tebrate creatifjn, indicates an arrangement which was large- ly to prevail in the vertcbrata of subsequent epochs. The Telcrj)eton of the Elgin sandstone ushered in the dawn of reptilian life ; it is the earliest of its class yet known to us. Fitted for a sphere of existence difi'ercnt from that proper to fishes, it presents to our view a new modification of the vertebrate plan. Its well developed limbs point to a character which was to come forth more prominently in succeeding periods. * Natural History of Lake Superior. 330 TRACES OF PLAN In 1726, Sclieuclizer detected, in the comparatively re- cent rock of ffiningen, a fossil which he set down as hu- man, styling it " homo diluvii testis," (man a witness of the flood.) ■••' This opinion did not stand the test of com- parative anatomy, and the supposed human relic turned out to be that of a large salamander. The time had not yet arrived for the advent of man ; long ages had yet to roll on before the consummation of the vertebrate type ; the preparations for man's appearance were not yet com- pleted. Nevertheless, in this fossil of Scheuchzer's, there was a prefiguration of the more perfect type which man's bony framework presents. In 1847, Professor Plieninger of Stutgardt found two fossil molar teeth, which must have belonged to a warm- blooded quadruped ; they were disinterred from a bone- bed in Wurtemburg, lying between the Lias and Keuper formations. The original owner of these interesting relics is supposed to have been an insect-feeder. A weU-marked tooth, pronounced on the highest authority, to have been that of a warm-blooded quadruped, implies adaptations of the vertebrate archetype of a far higher character than any yet indicated in previous geological records. Such a relic indicates associations of structure which are found in man himself; and at this point in the earth's history, we have the herald of the great mammalian class at the head of which man is placed — the first in nature, though the last in time. Certain bipedal footsteps in the new red sandstone of Connecticut, are recognized as those of birds. Man, the tiTie biped, was to appear in a subsequent and stiU distant epoch. But such early impressions and remains are not with- * It is agreed on all hands tliat the origin of tho human species is of comparatively modern date. All fossil human remains, those of Guadaloupe, for example, are withia the historical epoch. tX FOSSIL REMAINS. 331 out their instruction ; we may recognise in all these pre- existent beings the same type of skeleton, the beau ideal of which was to come forward in the time appointed, after the lapse of long ages. Fishes, reptiles, birds, and mammals, predecessors of man, presented in their frames anticipations of more perfect structures which characterize him. They had arrangements to protect the eye and the organ of hearing, a bony vault to contain the brain, and limbs for various fauctions necessary to their wellbeing. The Supreme could foresee that which was to come, and which He had pre-ordained ; the revelations of geo- logy enables us to take a retrospective view. But they do more ; they afford us the means of exercising a reflex faculty ; we can examine the first figure in the vertebrate series, and from that point look down the long vistas which are opened, to the period when man appears as the final and foreseen product of the one mighty plan — the last in time, but the first in the contemplation of Him who called them all into being. Precedent vertebrata shadowed forth certain peculiarities of frame and of psychical powers, which have their full, and evidently in- tended, significance brought out and manifested only in man. When he appears on the scene which had been so long Y^repared, and, as it were, waiting for liim, the con- summatidn of the earthly type comes out ;— in a goodly frame, with gait erect ; in eyes to contemplate, and men- tal faculties to appreciate, the beauty of the objects ari)und him ; in limbs to bear that frame upright, and carry it on in the fulfillment of its high sphere of duties ; and in liands to minister to the wants of the individual and • 80 Sodium, )■ 24 Iodine, 125 ) Lithium, 7 Calcium, 20 ) Sulphur, 16 Strontium, V 44 Silenium, )■ 40 Barium, GO ) Tellurium, G4 " Regarding," says Faraday, " chlorine, bromine, and iodine, as one triad, it will be seen that between the first and the last there is recognisaliK.' a wrll-niaikcd prt)gre8- sion of quahties. Thus chlorine is a gas, uiukr ordin- 364 CRYSTALLINE FORMS ary temperatures and pressures ; bromine, a fluid ; and iodine, a solid ; in this manner displaying a progression in the difference of cohesive force. Again, chlorine is yellow ; bromine, red ; iodine, black, or, in vapour, a red- dish violet."" In the higher chemistry of organized bodies we meet with another kind of organic groups ; " these are named Organic Types, the meaning of which is, that the atoms are grouped together in a certain mode, on which the properties or the compound so entirely depend, that pro- vided this grouping or arrangement be retained, great changes may be made in regard to individual elements, without changing the general character of the compound. This leads us to the very remarkable and important law of substitution, which has become so fertile in discoveries of late years."f In organic chemistry every compound represents a type, and all chemical changes are substitu- tions, but only like for like can be substituted, one metal for another, or chlorine for iodine, &c. In organic chemistry, the ari^angement of the atoms determines the character of the type. A certain arrange- ment gives acids, another ethers, and so on. As an ex- ample of such an organic type, Dr. Gregory gives the case of Naphthaline C^,,, H^., the character of which is that it is volatile and combustible. Now the hydrogen in this compound may be replaced, atom by atom, by chlorine, yielding a compound C20 Clg, which still retains the gen- eral characters of the type. But there is another form of substitution giving rise to liomologous sei'ies, in which hydrogen is replaced by cer- tain compound radicals which are themselves homologous and give origin, when substituted for hydrogen, to other * Faraday's Lectures on Non-Metallic Elements, pp. 158, 159. t Elementary Treatise of Chemistry, p. 265. AND CHEMICAL PROPORTIONS. 365 homologous series. The following tabular view will ren- der this jjlain : — Hydrogen H. Water HO. ' Mcthyle, Co H3 ' Oxide of Methyle, C, H3 Ethyle, C4 Hi E do. Ethyle, C4 H5 Propyle, Ce H; Butyle, Cs H9 1^ do. Perpyle, Ce H7 do. Butyle, Cs Hg ^Amyle, CioH,, do. Am_vlc, CioHiiO Taking methyle, the first in the series, we can see the simple relation which exists between it and all the mem- bers of the series. The second, cthylc, is derived from the first by adding two atoms of carbon, and two of hy- drogen. The third bears a like relation to the second, and so on throughout. The carbon equivalents form an even number, those of the hydrogen are odd numbers. It is far- ther worthy of notice, that the volatility of each is inversely as the amount of carbon and hydrogen, and, consequently, the density is in direct proportion to the amount of car- bon and hydrogen. The density and boiling point in- crease from the top to the bottom of the scale, in the order in which they stand in the above table. Methyle is a gas like hydrogen, requiring twenty atmospheres to reduce it to a fluid state, amyle is an oily fluid boiling at 311^ Fahr. The radicles in the first part of the table are all homo- logous with, and analogous to, hydrogen. And as hydro- gen, H, was the starting point in the series of radicles, (Ethyles,) so water HO is the starting-point of a new ho- mologous series formed from these radicles, forming ethers, as represented in the second series in the table. The first of these, oxide of methyle, C^ H^ 0, is a gas ^t ordinary temperatures, the others are Tujuids less volatile than ether, and so on. From this second series a tliini homologous series is 366 ' CRYSTALLINE FORMS formed, viz., the alcohols, by the addition of two equiva- lents of water ; one example may suffice : Ca H3 0, HO give methylic alcohol, &c. It may be observed that these series, ethers and alcohols, are also analogous as well as homologous, that is, their general characters are the same. " We can now see," says Dr. Gregory, " that the pro- gress of science must inevitably reduce the whole of or- ganic chemistry, in which we must remember only the same three or four elements are perpetually met with, to a collection of homologous series, in which every com- pound win have its natural place, indicative at once of its origin, its immediate derivation, and its properties both physical and chemical."* It is not necessary to maintain that all the laws re- ferred to in this section, or in any of the sections, are simple and original ; it is not necessary that we should regard any one of them as being so. We are at liberty to suppose that the very law of gravitation itself is de- rived from a simpler law, as is maintained by some in our day ; still the order in the derivative law would be a proof of order in the original law itself, and in the ar- rangements made in order to its operations ; thus, upon the discovery of the law of gravitation, the laws of Kep- ler were accounted for, but by a law orderly in itself, and havino' beautiful arrantrements made in order to its bene- ficent action. Most of the forms of crystals found in nature are derivative, but when we go back to the origi- nal forms, we find them, like the derivative, distinguished by the most methodical symmetry. On the same prin- ciple we may argue that should the laws at present acknowledged in science be resolved into simpler ones, it would still be found that tlie original laws, with the * Gregory's Elementary Treatise on Chemistry, pp. 2G4, 269, 272. AND CHEMICAL PROPORTIONS. 367 adjustments made iu order to their operation, arc of a recrular and niutuallv adaptive character. The forms of crystals, and the relations of chemical equivalents, if not simple, must, just because thc}^ are regular, proceed from forms or from forces, one or both, which are also charac- terized by regularity. From disorder there can flow only confusion ; order can proceed only from order. SECT. II. ADAPTATIONS OF INORGANIC OBJECTS TO ANIMALS AND PLANTS. Many of the adjustments which might be adduced under this head are so obvious that it is not necessary to dilate on them ; indeed, they can scarcely be made more impressive by any scientific treatment. While the ele- ments of nature obey their own methodical laws, they are so arranged as to form living organisms, and supply them with the needful sustenance. Each agent has its rule of action, but is made to co-operate with every other. Law is suited to law, property fits into property, colloca- tion is adapted to collocation, and the result is harmony and beneficence. The whole is dependent on every one of its parts, and the parts all lend their aid to the pro- duction of the whole. A break in a single thread of the complicated network would occasion the failure of the whole design. There are upwards of sixty substances, which, in our present state of knowledge, we must regard as uncom- pounded. Each of these has its own properties, and the Hystem is sustained by the joint action of all. Very pos- sibly the absence of any one of the elements, certainly the absence of any one of the thirteen more universally dill'used, would throw the mundane system into confusion. Eacli has a purpose to serve which could bo served by no 3G8 ADAPTATION OF INORGANIC OBJECTS other. Oxygen, so essential to animal breath and life, is the most largely distributed of them all, composing more than one half of the whole inorganic objects known to us. Hydrogen, the other element of water, no less necessary to living beings, seems to have a relation to everv living organism. Carbon is a main source to us of artiiicial light and heat. In order that it should fulfil this end, it is necessary that it should be a solid while evolving its light and heat, (a gas has little, and this only a momentary, power of illumination) ; this is pro- vided for by carbon being in itself always solid. But if the result of combustion had been also a solid, then the world would have been buried in its own ashes ; this evil is avoided by the carbon going off in carbonic acid, which is volatile. The mass is all glowing one instant, the next it is dissipated into air. "Carbon," says Faraday, "posses- ses every quality to render it adapted to its intended uses; not one property, however seemingly unimportant, could be added or taken away without destropng the whole harmonious scheme of nature, devised with such wisdom, maintained with such care."* Each of the powers and elements of nature is in itself potent, and capable of working destructive effects, but is checked and balanced by nice adjustments. What tre- mendous energies does oxygen display in the phenomena of combustion, and when in the condition of ozone ; yet how tranquil and passive as one of the elements of water, and as locked up in so many of the constituents of the earth's crust. The electric force held in balance in a single drop of water would, if let loose, exceed in energy the electricity of a thunder-storm. Man is placed in a state of things in which, as he is dependent, he is made every instant to feel his dependence. • Letters on Non-Metallic Elements, p. 277. TO ANIMALS AND PLANTS. 369 What a vast number of independent agencies must combine and co-operate in order to the life of organized beings ! It is wrong to talk of an organism develojiing itself by its simple and independent energy. Whatever be its internal nature — in which also, in our opinion, there is complexity and combination — it requires exter- nal agents in exact adaptation to it. All plants need nourishment, and this is supplied by inorganic matter ; all animals need nourisliment, and can be nourislied onlv by matter that has been organized, and this is furnished directly or indirectly by the plant. How beautiful that adjustment by which animals breathe of the oxygen of the atmosphere, and set carbonic acid free for the use of plants, wliile plants absorb carbonic acid, and set oxygen free for the benefit of animals ! Then all animated beings need moisture, which depends on the chemical laws unit- ing oxygen and hydrogen to form waiter, and also on beat to retain it in a state of vapour in the air, and on certain adjusted relations, in respect of quantity and weight, to the atmosphere in which it floats. All organized beings, too, depend on light coming in the needed proportion from a distant body, and on heat, the measure of which depends on the state of the central part of the earth, on the radiations of the sun, and on the temperature of the regions of space. A considerable change in any one of these essential conditions Avould be fatal to the whole an- imated beings on the earth's surface. But instead of dwelling on these familiar topics, we shall turn to, perhaps not so conclusive, but still to a less known set of facts, in wliich it lias been supposed that disorder reigns. We have, in a previous chapter, brought forward some evidences of ada])tatioii in Ibc march of events whicli preceded man's epoch, and wMi h li;ivc given rise to im- 370 "ADAPTATION OF INORGANIC OBJECTS portant changes on the earth's surface, to fit it as the dwelling-place of animals and plants, and apparently ef- fected with a view more especially to the advent of man. In the development of this scheme, a suitable vegetation was called into being, animal tribes were introduced, with the command to multiply, and finally, to man was com- mitted a power over every living thing. Our aim, in the present section, is to show that there are traces of fitness in the general aspect of the earth's contour, in the arrangement of its dry land and waters, and in the relations of its surface to temperature and moisture ; and that these, in turn, have some connexion, more or less evident, with the distribution of animal and vegetable life, and also with the wellbeing of the human family. The study of Physical Greography, which has of late years come into prominence, has little or no reference to those arbitrary divisions of the world which occupy the attention of the mere geographer. In examining the structure of the earth's surface physically, attention is rather directed to the valleys and elevations which diver- sify its surface — those furrows drawn by the hand of time, and the mountains which, by their upheaval, have so remarkably diversified it, and indirectly have such im- portant bearing on the existence and wellbeing of ani- mals and plants. Those dee]) furrows and prominent ridges, constituting so remarkable a feature of the earth, are lasting records of the great changes to which it has been subjected : we cannot suppose them to have been fixed by mere chance ; they bear distinct traces of sub- jection to those great principles which regulate aU the plans of Him, every part of whose works is adapted to every other. The investigations of observers in different ages have TO ANIMALS AND PLANTS. 371 establislied the following leading truths in regard to this subject. Land predominates in the nortliern hemisphere, water in the southern ; the lands comprising the old and new worlds stand at right angles to each other ; the new world is perpendicular to the equator, the old parallel to it. In reference to the contour of the dry land, it has been observed, that the southern ends of the old and new worlds terminate in a point, while they widen toward the north ; that the southern points are high and rocky; that the continents present, to the east of their southern extremities, a large island or grouj) of islands ; and that each continent has a large gulf to the west. Humboldt has indicated the parallelism of the two sides of the Atlantic ; the projecting parts of the one correspond to the gulfs of the other. Steffens has remarked, that not only do the great continents expand towards tlie north, and become narrower toward the south, but that the same is true of their peninsulas also. He speaks, like- wise, of the grouping of masses of land two and two together, and points out an isthmus or chain of islands uniting them. Guyot, in his " Earth and Man," enunciates the follow- ing great laws, which apply to all continents in regard to their relief or elevation : — All increase gradually in height from the shore to the interior ; in all the conti- nents the maximum (if elevatimi is not ill llio centre — hence there are two slopes of unequal length, and in the mean, one of these slopes is always at least four or five times greater than the otlier ; and the height of the jilaiiis and of the table-lands increases at the same time with the absolute elevation of the mountains. Tn the old World, tli(tugh the j)rincij)al slo]»e is towurd ihe north, we still observe a gradual decrease of the reliefs from 372 ADAPTATION OF INORGANIC OBJECTS east to west : in the same manner, in the new world, while the principal slope is from the west to the east, it can be shewn that the reliefs go on gradually increasing from north to south, as in the old world.* Generally speaking, although the mountains increase in elevation from the poles to the tropical regions, the greatest heights are not exactly at the equator ; in the old world they occupy the vicinity of the tropic of Cancer, and in the new, are near the tropic of Capricorn. To use the words of Guyot, — "A great law, a general law unites all the various systems of mountains and of table-lands which cover the surface of our globe, and arranges them in a vast and regular system of slopes and counter- slopes." From all this it is evident that the position of the great masses of land, the forms of their coasts, the situa- tions and relations of their mountains, table-lands, and plains, have not been left to chance. A casual glance at a map, or a cursory examination of an individual country, may leave the impression that there is a want of definite order, that all is in inextricable confusion ; but careful examination of the entire wide surface of our globe, and of the relations of its various parts, conclusively demon- strates that He who commanded the dry land to appear, accomplished His purpose according to a predetermined plan, the issues of which must have been foreseen by Him, even as they can now be seen by us. An inquiry into the special modifications, in their relations to climate and the distribution of living objects, enables us to see what fatal consequences must have resulted, so far as the present economy of things is concerned, if the plan and modifica- tions had been different. A water surface is slowly heated, and the consequent * Guyot, Earth and Man, p. 50. i TO ANIMALS AND PLANTS. 373 evaporation produced lias an additional retarding effect ; such surface is also slowly cooled by radiation. A land surface, on tlie other hand, becomes rapidly heated, and as rapidly parts with its heat. Change of temperature in water occasions a change of position in its particles ; no such effect is produced on the land surface. The sun's rays are weakened in their passage through the atmosphere, owing to the presence of clouds and mists, and the increased density of the lower strata ; the por- tion of that medium nearest the earth, however, receives its temperature principally through radiation from the soil. The variety of surfjice, whether in respect of smoothness or irregularity, elevation or depression, water or dry land, necessarily occasions also a corresponding- difference in the amount of heat received by different countries ; from which it appears that terrestrial as well as atmospheric conditions modify the distribution of the heat which we derive from the great central luminary of our system. The processes of heating and those of cooling are slower and less sensible on water than on land, and the portions of air in contact with these surfaces respectively, are affected by the peculiarities of each : over the former the atmosphere contains more moisture, and is of more uniform temperature, than over the latter. Lands far from the influence of the sea have great extremes of heat and cold, whereas maritime districts have a more uniform temperature throughout the year. Tlic division into torrid, temperate, and polar zones, though generally ap- plicable as regards the climates of our earth, is greatly modified by local configurations of surface, so tliat there lire no exact lines of dfuiarcation sei)arating tlie torrid from the temperate zone. Tn tlie words of Hundioldt, The temperature is raised by the ])roxiniity of a western u riM 374 ADAPTATION OF INORGANIC OBJECTS coast in the temperate zones ; by the divided configura- tion of a continent into peninsulas with deeply-indented bays and inland seas ; the jorevalence of southerly or westerly winds ; chains of mountains acting as protect- ing walls against winds coming from colder regions ; the vicinity of the ocean current, and the serenity of the sky in summer : it is lowered by elevation above the seas, when not forming part of a plain ; the compact configura- tion of a continent having no littoral curvatures nor bays; the vicinity of isolated peahs ; mountain chains whose mural form and direction impede the access of warm winds ; and a cloudy summer sky, which weakens the ef- fects of the solar rays." That comparative sameness which would result from uniformity of surface, exposed to regular amount of solar radiation at different seasons of the varying year, is coun- teracted by special modifications of our dry land and ocean; and hence the variety of climate, and corresponding diver- sity in the vegetation clothing the earth, and in the living beings that people it. The atmosphere near the earth's surface, or in contact with it, is, as a whole, much warmer in the vicinity of the equator than at the extreme polar regions. This hotter and higher air has a tendency to ascend, and the colder and heavier, an equal tendency to rush in from all sides and supply the place of the former. To such dif- ferences of temperature may generally be referred all those atmospheric currents which constitute the different winds.* The direction of these currents towards the equator might be uniform if the earth did not rotate, and if its surface were level. The currents from the vicinity of the pole have little rotatory motion, but in * For some ingenious speculations on Uiis subject, we would refer to Lieut. Maury's recent and excellent work on tiie Physical Geography of the Soa. ■ TO ANIMALS AND PLANTS. 375 theiv prog;rc^s toward tlie equator tliey reach successively portions of the earth's surface, which revolve more and more rapidly, and thus leave them behind, (if we may so speak,) and then they appear to blow in a direction con- trary to that of the earth's rotation. Hence the cur- rent from the north becomes converted into a north-east, and that from the south into a south-east wind. Such is the orio;in of those re2:ular winds called the Trades. The land and sea breezes of warm climates depend on the same general cause ; the cold air from the sea during the day flows in to supply the place of the air which is more rapidly lieated over the land, (and consequently ascends,) the converse happening at night. The aerial currents spoken of, and their more regular modifications, also exercise a greater or less influence upon the ocean surface, giving rise to interchanges in its parts. There is a similarity in the efi^ects produced by heat upon the sea, to those produced by the same agent on the aerial ocean. The warmer waters of the equatorial sea have a tendency to flow towards the poles, the colder and heavier portions forming an under current toward the equator. Differences in the amount of saline matter, occasioned by excessive evaporation at certain points, or by the influx of large rivers, producing differences in the specific gravity of the ocean water,* necessarily also give rise to currents. Whatever jjower, however, sets the water in motion, the direction of the current is variously modified by the con- tour of the land. Moisture is being continually evaporated in an invi- sible state, and mixes with the atmos])liere ; an abso- lutely dry air is therefore almost an ini])ossible occur- rence, thougli there may be endless modifications in the amount of nnjisture depending on various causes. The • Wc would again rt-fer to Llout. Maury's work for di^tails on tlils InliTostliiR subject. 376 ADAPTATION OF INORGANIC OBJECTS quantity differs according to elevation above the earth's surface ; the diminished density of the air upwards is accompanied also with decrease of the absolute amount of vapour of water contained in it. In the vicinity of the equator the suspended vapour is abundant, owing to the excessive heat^ and the extent of water surface ; it diminishes toward the poles ; it is generally greatest over the open sea, and decreases from the coast to the interior of continents. From this brief account some idea may be entertained of the remarkable relations between the genial beams of the sun reaching us from a distant point in space, and the atmosphere, dry land, and water of our world. These, again, have a connexion with the distribution and well- being of the animals and plants which have been distri- buted over its surface with bountiful hand. We may now briefly examine some of the consequences of the present arrangements of the earth's surface. Not the least remarkable of these is determined by the gene- ral position of the highest elevations. The concentration and grouping of the high and extensive mountain sys- tems towards the equator tend to reduce the temperature of that region ; and the great extent of its water-surface contributes to the same effect. If the equatorial surface had been all land, and that land all plain, it is obvious, for reasons already stated, that the whole of that part would have presented the character of a parched desert, and, in reference to animal and vegetable life, would have been a dead waste. One of the agents necessary to the development of living organisms, namely, heat, would have been supplied in excess, and another, no less essential, namely, moisture, would have been withheld. By the complicated, but nicely adjusted, arrangements we have already described, the present constitution of the earth's TO ANIMALS AND PLANTS. 377 surface determines enough of the agents in question for the wellbeing of vegetable and animal life. If the elevated mountain ranges had been all grouped toward the higher latitudes, eternal snows and ice would have debarred animals and plants from a large extent of surface at present occupied by both. A combination of all these arrangements, namely, extensive flat land at the equator, and high land at the poles, would have neces- sarily limited the range of living forms, which must have been chieflv confined to a comparatively narrow zone be- tween the two extremes. Even when we consider the present asp(ict of limited portions of the earth's surface, we are struck with the beauty of the adaptations. Mixtures of two masses of air of different temperatures, and with dissimilar amount of moisture, will occasion condensation of that moisture in the form of mist or rain. The ascent of the hot and humid air of the equator brings it in contact with strata lower in temperature, and condensation of moisture is the result. The same may happen when it moves on as an overflowing current towards the north and south. Nor is it to be forgotten that there is another condensing agent ; we refer to land of high elevation. Moist winds meeting with such an obstacle to their flow, have their onward progress aiTCsted, and their horizontal changed into an ascending course ; the consequence is, that the mass of air, becoming cooled by contact with other and colder air, and with the land surface, loses its power of retaining the same amount of vajwur, and condensation of moisture is the result. 1 n the words of Guyot, — " The mcmntain chains are the great condensers, })laccd here and there along the continents, to rob the winds of tin ir treasures, ti» serve as reservoirs for the rain waters, ami to distribute them aftcr^vard8, as they are needed, over 378 ADAPTATION OF INOKGANiC OBJECTS the surrounding })lains. Their wet and cloudy summits seem to be untiringly occupied with this important work. From their sides flow numberless torrents and rivers, carrying in all directions wealth and life,"* In the new world, the chain of the Andes — its "great backbone" — is situated not far from the western border ; to the east of this vast range are extensive plains, with interspersed secondary mountain ranges ; and this pecu- liarity of conformation has a most important and neces- sary relation to its climatic peculiarities. The trade- winds from the Atlantic, in their progress first reach the eastern slope, where the secondary chains of mountains condense part of the moisture in refreshing showers, and, finally coming in contact with the great and elevated principal range, the air is robbed of most of the vapour which remains. Hence a continual flow of water down the eastern slope, clothing that fertile region with the richest vegetation, and giving it the largest river sys- tems in the world, A necessary result of this influence exerted on the moist trade-wind in its progress to the west, is, that by the time it reaches the western side of the Andes nearly all its moisture has been lost, and a line of coast on the Pacific presents the character of an arid desert. The extent, however, of this region of draught is very small, compared with that which profits at its expense. The advantage derived from the arrange- ment on the one side of the Andes, far more than com- pensates for the disadvantage, and then this latter is still farther lessened by local peculiarities, for the Chilian de- sert would have presented greater latitudinal extent, if the Cordilleras toward the north had been higher, or the continent of greater breadth. Imagine a difierent arrangement of surface ; the great * Guyofs Earth and Man, p. 144. TO ANIMALS AND PLANTS. 379 mountain cliain, for example, transferred to the eastern, instead of occupying the western side ; the consequence would have been that the Atlantic trade-wind must have had its progress arrested, and its vapour condensed, at a comparatively early part of its course ; the ocean giving up a portion of its waters to the passing wind, would have received them back again at no great dis- tance in space, and after a short lapse of time ; no ex- tensive river systems could have possibly existed as at present ; — in a word, the whole influence of the genial wind would have been lost, the descent to the west would have been far more extensive, and the chans^-e in the land surfiice, and the resulting effects on climatic pecu- liarity, would have resulted in a very different distribu- tion of organic forms, would have given rise to new fea- tures in the zones of animal and vegetable life, and cliauged the habitations of man, and the relation of one part of mankind to another. We may now direct our attention to another part of this wide subject, to modifications which have respect to the waters of the ocean and their cun-ents. It has been already stated that there is a tendency to a general transference of the warmer equatorial waters to the north and south, and of the colder polar waters towards the equator, subject to modification . in consequence of the earth's rotation. Now the configuration of the land sur- face determines peculiarities in the distribution of the great currents, Avhich exert no mean influence on the distriljutiuii of organic forms. The great equatorial current of the Atlantic has the largest mass of its waters Ijjfurcated liy the projecting point of Cape Ban Iloque, on<.' part being deflected to tlie soutli, along the ccjast of Brazil, hence called the Brazil current ; while the re- maining and largest passes into the (Julf of Mexico, and 380 ADAPTATION OF INORGANIC OBJECTS then issues from the north-east extremity of the same, under the name of the Gulf Stream, and at a tempera- ture exceeding 80° of Fahrenheit's thermometer. At its exit from the narrow passage between the point of Florida and the island of Cuba, and for some distance be3^ond, its flow is comparatively rapid and northwards, till the cold currents from the north, and the change in the con- tour of the coast line, produce such an influence that its direction becomes north-east.'''" Nevertheless it still re- tains a high temperature ; in lat. 41° N. it is at 72'5° F., and 63'5° F. on the outer border of the stream. Its in- fluence is admitted to extend to a large part of north- western Europe, and it bears with it evidence of its pre- sence, and of the regions whence it flows, in the form of tropical seeds and fruits, &c., which are stranded on the shores bathed by its waters, and this even as far as North Cape. The efiect of such a body of warm water (at Cape Hatteras, Professor Bache found its temperature little altered at a depth of 3000 feet) upon the distribution of marine animals and plants might be expected ; but this influence extends also to the lands along whose shores it moves. The late Professor E. Forbes has shown its effect as regards the distribution of animal forms on the British coasts, the general Fauna of the German Ocean being different from that of the Atlantic border-line. This difference we have shown to be not less marked in regard to marine vegetation ; certain species of sea-j^tlants abundant on the Devonshire coast, range also alona; the Atlantic border as far as the Shetland Islands, while most of them are wanting over a large proportion of the * This explanation is not deemed sufficiently satisfactory by some, and we would re- fer to the remarks on this subject, in Lieut. Maury's work already quoted. We have chiefly to do with the course of the current. TO ANIMALS AND PLANTS, 381 coasts Avaslied by the German Ocean.* The general miklness of the western coast of Britain, as compared with the eastern, is mainly to be attributed to the com- paratively warm water of the Atlantic. The influence extends to the land vegetation of the continent ; the con- sequence being that the line of cultivation extends nearly to Xorth Cape, and barley may be grown as far as 70^ N. latitude. It appears that while there is a general plan regulating the relations between our earth's surface and the intiucnce of the central luminary of our system, there are modifi- cations affecting the more local distribution of heat and moisture ; and these are associated with certain features of organic life, inasmuch as there is a relation between the amounts of the necessar}^ agents and the copstitution of animals and plants. We cannot avoid coming to the conclusiun that there are indications — at least in our hemisphere, that great centre whence civilization has ex- tended — of suitable physical conditions, which were not brought about by mere chance. Knowing the connection which exists between the na- ture of the surface, whether land or water, and the influ- ence of the sun's rays on the temperature of our atmos- phere, is is quite legitimate to speculate regarding altera- tions of climate as related to changes of surface. Those great revolutions which have taken place at dif- ferent epochs of our earth's history, and the corresponding pliases which luive occurred in animal and vegetable life, are among the more interesting points which occupy the attention, and are revealed by the investigations of the geologist and of the paUcontologist. In man's compara- tively brief period, such liave not been distinctly exhibi- ted on any great scale ; nevertheless witli no inconsider- • Bee Dr. Dickie's Paper In I'rocoudlngs of nrltli^h AASociatloii for 1862. 382 ADAPTATION OF INORGANIC OBJECTS able degrse of certainty, the pliysicist can sliow what general climatic changes would follow the submergence of a continent, and the increase of water surface, or the converse. Farther, the average height of any portion of land above the level of the sea, can be shewn to exercise a distinct influence on the climate of the region, and con- sequently, on the beings which inhabit it. Sir Charles Lyell in his " Principles of Geology," has shewn how the numbers and distribution of animals and plants are affected by changes in the physical geography of the earth, and that these changes may also promote or retard migrations of species, or alter the physical conditions of the localities which they inhabit. " There are always says he, " some peculiar and characteristic features in the physical geography of each large division of the globe, and on these peculiarities the state of animal and vegetable life is dependent." Mr. Hopkins, in his introductory address to the meet- ing of the British Association at Hull, has very clearly shewn the relation between the climate of northern and western Europe, and the present configuration of the American coast line, in reference to the direction of the great Gulf Stream. He remarks — " It is to the enormous mass of heated water thus poured into the colder seas of our own latitudes, that we owe the temperate character of our climate and not only do the maps of M. Dove enable us to assert distinctly this general fact, but also make an approximate calculation of the amount to which the temperature of these, regions is thus affected. If a change were to take place in the configuration of the surface of the globe, so as to admit the passage of this current directly into the Pacific, across the existing Isthmus of Panama, or along the base of the Kocky Mountains of North America into the North Sea — a TO ANIMALS AND PLANTS. 383 change indefinitely small in comparison to those which have heretofore taken place — our mountains, which now present to us the ever-varying beauties of successive sea- sons, would become the unvarying abodes of the glacier, and regions of the snow-storm ; the cultivation of our soil could be no longer maintained, and civilisation itself must retreat before the invasion of such physical barbarism." We arc anxious not to stretch the argument beyond what it can bear. Where the relations are so many and complicated, we are not entitled to say that no other sys- tem could have served the same ends ; but we think that we can discover proof that there is a system. We can see that certain changes unless counterbalanced by other changes, would have been fatal to many^of the animated beings on the earth's surface. We can see, too, that the present condition of the globe is, in fact, suited to the existing distribution of organized l)cings ; and we know of no means by which plants and brutes could have adapted themselves to an essentially different state of the earth. It is evident that every part is suited to every other. " The mind," says Lieut. Maury, " is delighted, and the imagination charmed, by contemplating the physical arrangements of the earth fi'om such points of view as this which we have now before us ; from it, the sea, and the air, and the land appear each as a part of that grand machinery upon which the wcllbeing of all inhabitants of earth, sea, and air, depend ; and wliicli, in tlieir beautiful adaptations, afford new and striking evi- dence that tlicy all have their origin in one omniscient idea, just as tlie different i)arts of a watch may be consi- dered to have Ijcen constructed and arranged according to one liMiiian design." We fully acknowledge, in regard to man, lliaL he is capable of suiting himself to a variety of conditions and 384 ADAPTATION OF INORGANIC OBJECTS circumstances, but, in this respect, he stands ahnost alone in creation ; and we cannot view him apart from animals and plants, for his existence is intimately linked to theirs. His range in latitude is certainly very extensive, from the snows of the Artie lands — wliere those outposts of humanity, the Esquimaux, pass their lives between the extremes of satiety and starvation — to the tropical zones, where their swarthier brothers are exposed to the heat of a meridian sun. But it is not to be forgotten that while he can exist in such widely different circumstances, there are certain terrestrial conditions necessary to the develop- ment of his higher nature and qualities. " The distri- bution of man," says Guyot, " over the surface of the globe, and that of other organized beings, are not founded on the same principle. There is a particular law which presides over the distribution of the human races, and of civilized communities, taken at their cradle in their in- fancy ; a different law from that which governs the dis- tribution of plants and animals. In the latter, the degree of perfection of the type is proportional to the in- tensity of heat, and of other agents which stimulate the display of material life. The law is of physical order. In man the degree of the perfection of the types is in proportion to the degree of intellectual and moi-al im- provement. The law is of moral order. . . . Here is the reason that the Creator has placed the cradle of man- kind in the midst of the continents of the north, so well made, by their forms, by their structure, by their climate, to stimulate and hasten individual development, and that of human societies." When God gave the earth to the children. He meant it to be to them a source of something more than mere sustenance. There are scenes spread all over its surface which have delighted or roused the soul of man, and TO ANIMALS AND PLANTS. 385 helped to shape his character and his history. The fer- tile field, the pleasant dale, the murmuring rill, the gently-flowing stream, the rugged mountain, the bold headland, the thundering cataracts, these have all been the means of soothing, of exciting, or awing the spirit of man. The vegetable productions enhance and vary the effect by the lightness and gracefulness of their forms and harmony of their colours, by their tangled luxuriance in our meadows and by our rivers' banks, or by the sombreness of their hue and depth of shade which they furnish. These aspects of nature have all had thou* in- fluence in raising up new ideas and fresh feelings in man's soul. The j^hysical characters of a region, the na- ture of its surface whether flat or hilly, its soil and minerals, the size and flow of its rivers, the mountain chains which cross it, and the bays of the sea wliicli in- dent it, the clearness or cloudiness of its atmosphere — all these have moulded to some extent the psychical pecu- liarities of man, and determined his tastes, his pursuits, and his destmy. And there are still higher views to be taken of human- ity. " God hath made of one blood all nations of men for to dwell on all the face of the earth, and hath determined the times before appointed, and the bounds of their hal)i- tation." As the drama of our race's history is only being acted, we cannot see the issue ; but we are convinced that in this allotment there was a reference to the devel- opment of man's mental faculties, and ultimately to his moral and religious elevation. We should leave a wrong impression if we did not here state our belief that our earth, while ada])ted to man, is adapted to him ;is ;i being fallen, IVail and depraved. Our earth had a jfaradisc uj)on it only fur a briel" jxTind, and within a naiTOw range ; and, Inily, an Eden would 386 ADAPTATION OF INOEGANIC OBJECTS not be suited to man with his present character. We frankly acknowledge that we could not comprehend the suitableness of many of the physical conditions and ac- tions of our globe, of its waters and its vapours, if we regarded man as a pure and holy being, who did not re- quire to be restrained from evil by physical barriers, who needed not suffering to punish and to purify. Our earth, while it affords nourishment to man, yields it in such a manner that man must toil for it, and, in toiling for it, is kept from much sin. Physical geography announces, as clearly as Scripture, that man must eat bread in the sweat of his face. Not only so, our soil and atmosphere have chilling damps, and unwholesome heats, and dele- terious ingredients, which breed and cherish disease, and help to bring man to the grave. These are essential parts of the economy of things in which man is placed. In short, our eartli was prepared for man as possessing sinful inclinations, and needing to be exposed to suffering. Let us add, that it has been prepared as the scene of the action and passion of Him who must " needs suffer many things," and who had to say, " the foxes have holes, and the birds of the air have nests, but the Son of man hath not where to lay his head." But " unto us a child is born, unto us a son is given," and " this same shall comfort us concerning our work and the toil of our hands." We are convinced that not a few of the conditions of the earth have a reference, more or less direct, to the diffusion of Christianity as the only element fitted to regenerate our world. As the leaven is only yet leavening the mass, we cannot discover its full relations to the agents among which it is placed. But as the past condition of the earth was an anticipa- tion of the present, so the present points on to the future. We do not believe that the present is the consummated TO ANIMALS AND PLANTS, 387 state of the earth. Just as among the old geological vertebrates, there were members which had not unfolded all their capabilities, so, in our present earth, there are agencies at work which have not completed their office. A grand plan of prophecy is advancing both in the phy- sical and moral world, and we live in the expectation of a coming era, when the streams which have run for ages alongside of each other will unite, and yield, at the same time, a nobler condition of the earth's surface, and of the spiritual character of its human inhabitants. " They shall not labour in vain, nor Ijring forth for trouble/' " Instead of the thorn shall come up the fir-tree, and in- stead oi^the brier shall come up the myrtle-tree." "The cliild shall die an hundred years old." CHAPTER XIII. THE HEAVENS. SECT. I. ORDER IN THE MOVEMENTS OF THE HEAVENLY BODIES. / The ancients appealed with great confidence and evi- dent delight, to the heavens, as fitted ahove almost everything else, to prove that there is in nature, or above it, a presiding Intelligence, The spectres of which they stood in awe were either a grim fate or an unsteady chance, and from these they felt that they could be most readily dcHvered by the light which shone from the heavenly bodies. The argument was perfectly conclu- sive of the end proposed by those who advanced it, and it was so, notwithstanding that they were not able to shew whence the order to which they pointed proceeded. They observed that the movements of the celestial bodies were harmonious ; that there was, in consequence, a beneficent succession of day and night, and of seed-time and harvest, summer and winter, cold and hot ; that the motions of the very stars, which they styled planetary or wandering, were orderly — their apparent regularities obeying a higher law of order ; that there was a cycle for eclipses, whose return, therefore, could be predicted ; — and they argued, we believe legitimately, that the " music of the spheres" had been arranged as certainly as the ORDER IN TUE HEAVENLY BODIES. 389 concord which comes from a concert of musical instru- ments. We are justified in inferring that there has been inteUigence exercised in the production of the harmonies of music, whether we are or are not able to shew hoAv the tones are produced ; and, on a like principle, we are entitled to conclude that the harmony of the heavens does not' arise from the concurrences of chance, even when we cannot unfold its nature with perfect accuracy. Theo- logy has not been employing this argument so frequently for the last age or two, but it is because the old spectre, raised in the darkness of heathenism, has disappeared, and it is now more terrified by another delusion, that of pantheism, which has originated in the deception of the eye when gazing on a brighter light. But the argument drawn from the heavens is as conclusive as it ever was, and can now be expounded more fully and satisfactorily. We mean, in the brief survey which follows, to begin with the Solar System, and thence rise to the region of the Sidereal Heavens. In all, about seventy planetary bodies — jilanets, planetoids, and safrellites — are moving round the sun, or round each other in the most regular manner. Each of them is of an oblate spheroid shape ; rotates round its own axis ; moves in an elliptic orbit, with a sun or a planet in one of the foci ; has a fixed length of day, that is, time of rotation on its axis ; and a fixed length of year, that is, time of making a revolution round its pri- mary. The rotatory motions and the revolutionary mo- tions of the planets round the sun, and of the primaries round their secondaries, are all, with the exception of those of the satellites of Uranus, in one and the same direction, fri)m west to cast. All these bodies arc held in their spheres by a central force, of which Newton gave us the pr(;por(ional ex])r(>ssion. ^Pliesc may not be the 390 ORDER IN THE MOVEMENTS ultimate expression of the laws of nature, but thoy are the obvious forms in which thej present themselves to human observation. We have spoken of the orbits and movements of the planets as being regular, but this is true only approxi- mately. There are irregularities in them all, and appre- hensions were at one time entertained that these mio-ht go on increasing, till the whole system became hope- lessly deranged. But it was shewn, by the eminent con- tinental philosophers of last century, that all these are periodical, or balanced one by another. The earth's orbit, at this present time, is approaching nearer the circular figure ; but it has been demonstrated, that after a time it will become more elongated, leaving the length of the year and the mean temperature of the earth un- changed. The obliquity of the ecliptic — that is, the incjination of the earth's axis to the plane of its orbit — is at present lessening ; and as the seasons depend on this obliquity, which allows the sun to shed his full ra- diance on different portions of the earth at different times, it was feared that they, and all on the earth which depends on them, might be seriously affected by the change ; but it can be shewn that the obliquity will, in course of time, begin to increase, and that the variation, whether of increase or decrease, cannot sensibly affect the seasons. The moon's mean motion has for some time been increasing ; this is due to the diminishing eccentricity of the earth's orbit ; but in the course of time the eccentricity of the earth will begin to increase, and the moon's mean motion to diminish. The planes of the planetary orbits vary in their positions, but all the variations are periodical, and can lead to no inconveni- ence. When these questions were still unsettled, the apprehensions of derangement arose chiefly from the OF THE HEAVENLY BODIES. 391 perturliations of Jupiter and Saturn, each of whicli is as large as all the planetary bodies then discovered put to- j::ether. Long and anxious calculations were instituted on this subject by Lagrange and Laplace : these cannot be detailed without the aid of the highest mathema- tical analysis, but the result may be given. Laplace found that " there existed in the motion of Saturn an inequality, the period of which is 929 years, and in the motion of Jupiter a corresponding inequality, which is affected with a contrary sign, and whose period is nearly the same — the difference between the two scarcely amounting to a degree in a thousand years. This was balm to the apprehensions of philosophers, for all fears as to the probable disorganization of the frame of nature evaporated, and the explanation of Laplace produced the true u loxitjuoittGig, by which astronomers signified the restitution of things to their former state."* It is thus proven that, looking to the law of gravitation, and the disposition of the various planetary bodies in reference to the sun and each other, the solar system has a remark- able principle of stability in the midst of constant change. Connected with the Solar System there is a still greater number of comets. These used to be regarded even by astronomers with feelings of alarm, as ajiparently disturb- ing rather than liarmonizing agents. Byron speaks of "A pathless comet and a curse, The menace of the universe." The impression was tliat they api)cared and disappeared in the most capricious manner, and tliat the earth might regard itself as fortunate if it did not come within tlie sweej) of their tails, whicli at times spread themselves • Smytirs Celestial Cycle, vol I., p. 2Ct 392 ORDER IN THE MOVEMENTS. through a space of 180,000,000 miles. But it has now been demonstrated of some of them, and may he inferred of all, that they obey laws as constant as those of the planets themselves. They seem to consist of floating vaporous matter through which the stars can easily be seen. It has been ascertained that forty of them move in elliptic orbits. Some of these are comparatively small, being within the orbits of the known planets ; others extend much farther into space. Neptune revolves round the sun at a distance thirty times that of the earth ; but the great comet of 1680 moves in an orbit exceeding that of Neptune nearly as much as it exceeds that of the earth — the distance of the comet being 853 mean distances of the earth. The period of the revolution of a number of them has been ascertained, and the time of their re- turn can be predicted. It should be added that a few of them seem to move in hyjoerbolic curves, while a large number are said to have curves sensibly parabolic. Though we do not know the ends contemplated by these wanderers into space, nor, indeed^ by comets generally, yet we know that they obey the same law as the planet- ary bodies, and reasoning from analogy we may conclude with Newton, that they carry with them, and dispense through wide regions a beneficial influence. We are now to pass on from the sun and planets to the contemplation of the stars. The distances of some of the nearest of these stars has been ascertained, and shew us that in going from the outer planet to the nearest body of the sidereal regions, we have leapt across an in- conceivable void of twenty-one billions of miles. Others are supposed to be so far distant, that light, which travels from the sun in eight minutes, would require millions or even thousands of millions of minutes to come from them to our earth. It foUows that the stars which we OF THE HEAVENLY BODIES. 393 now see are stars as they existed many long ages ago. There is thus opened to us a glimpse not only of regions of space, but of periods of time stretching far into infinity. The telescope shows within its range one liundred millions of self-luminous bodies like our own sun. These are collected in many cases into groups with regular shapes, and, in not a few cases, arc in binary, or ternary, or multiple combination with each other. We can discover even by the naked eye that the stars in some places are gathered into clusters. Thus six or seven stars are seen by the naked eye as forming the Pleiades. The telescope shows that in this constellation there are nine or ten times the number of stars collected together and separated from the rest of the heavens. The number of such clusters is very great, and they may be discovered by artificial glasses, here and there, over the whole surfiice of the heavens — but more numerous in some places than in others, more numerous in par- ticular in the northern than in the southern hemisphere. The stars in so many of these clusters are so many that they cannot be counted ; but on a rough calculation it would appear that many of them must contain ten or twenty thousand stars, in an area not more than the tenth part of the moon's apparent disc. Some of these groups are of an irregular shape, which it is difficidt to classify, or even to describe ; but a large number of them assume such regular forms, as to show that there is some princi- ple of order or combination among them. The most common form is stated by Sir J. Herschcl to ])G the circular, or the elliptic of various degrees of ec- centricity, from moderately oval forms to ellipses so elon- gated as to be almost linear. ■=^' Dr. Robinson, in describ- • Outltacs of Astronomy. 394 OKDER IN THE MOVEMENTS ing the discoveries made by Lord Kosse's telescope, says they may be separated into three classes ; those which Fig. T5.* are round, of nearly uniform brightness ; those which are round, but appear to have one or more nuclei ; and those which are extended in one di- rection, so as to become long stripes or rays.f It should be added, that although there can be no doubt as to the regular character of the forms assumed by distant groups, yet as won- derful changes are made in their appearance by higher optical pow- ers, we are not at liberty to assume that we have ascertained their forms with per- fect accuracy. Thus some of the nebulae which presented * Fio. 75. Cluster in Hercules. + Transactions of Royal Irish Academy, 184T. i Fio. 76. Annular Nebula in Lyra. Fio. 76.t OF THE HEAVENLY BODIES. 395 the appearance of a spherical body to Sir John Herschel's eighteen-incli reflector, have been transformed by Lord Rosse's six-feet speculum into a luminous spiral of unequal convolutions, which are prolonged at both ex- tremities into granular globules. " Almost every new observation appears to confirm the fact of that curious tendency to spiral arrangement in these nebulous masses, of wliich mention has been so frequently made."* Sir John Herschel discovers in these aggregations of stars the operations of physical laws. " Their round form clearly indicates the existence of some general bond of union of the nature of an attractive force, and in many of them there is an evident acceleration in the rate of condensation as we approach the centre which is not re- ferable to a merely uniform distribution of equidistant stars through a globular space, but marks an intrinsic density in their state of aggregation greater in the centre than at the surface of the mass."f The same distinguished astronomer J regards it as a general law in the constitution of extended nebulie, that their interior or brighter strata are more nearly spherical than their exterior or fainter, their ellipticity diminishing as we proceed from Avithout inwards, a character which he represents as favouring, though not conclusively, " the idea of rotation on an axis, in the manner of a body whose component parts have such an amount of mutual connexion as to admit of such a mode of rotation, and of the exertion of some degree of i)ressure one on another." Some of the late disclosures of Lord Rosse's telescope, in regard to the prevalence of the spiral form in nebular groups, may so far effect these S2)ecula- tions, but in doing so they open to our view a more won- derful harmony, the law of which has not been determined. • PreMdcnt'n iwMross to British Ausoclatlon, ia'>3. t OutllncB of Aslronoiny, p. 5U3. % Observations ftt Copo, p. 8. 39G ORDER IN THE MOVEMENTS The Milky Way, whicli spans our heavens so conspicu- ously, is not a cluster of stars, but a succession of clusters. Our sun is one of the stars comj)osing this system, and is supposed to be placed not far from the centre, but nearer the one side than the other, and in one of the poorer or almost vacant parts of its general mass. Sir Fio. 77.* W. Herschel thought he was able to number eighteen million stars in this girdle, and his son speaks of it as consisting entirely of stars, scattered by millions like glittering dust on the background of the general hea- vens. That there is some sort of concentration in this zone is evident from the statement of Struve, that there are nearly thirty times as many stars in the centre of the stratum as in the regions near the extremities. - On looking into the concave of the heavens, there are perceived at unmeasurable distances, luminous masses which look like £eecy clouds, and have been called ne- bulae by astronomers. Upv^^ards of two thousand of these '' world islands" have been discovered in the northern, and upwards of a thousand in the southern hemisphere, by the telescope employed by the Herschels. According to Sir W. Herschel's estimate in 1811, they cover aTo^h part of the whole heavens. They were at one time sup- * Via. 77. IleiRcheVs section of the Milky Way. Tlio Milky Way appears more brilliant in the direction of F, of D, of B, tliaa in tliat of E, C, and A. OF THE HEAVENLY BODIES. 397 posed by certain speculators to consist of a sort of lumi- nous matter, or star-dust, out of which worlds arc being made even now by general law. This supposition has not been confirmed by later speculation. Within these few years, not a few of these nebulfe which were regarded as being most certainly luminous vapours, have been shewn to be stars. The magnificent telescope of Lord Kosse, not long after it began to be used, shewed that the great nebula in Orion, which was supposed to be one of the most unresolvable of them all, consisted of clusters of distinct stellar bodies. Since that time, nebula after nebula has been resolved by Lord Rosse's telescope, and another of less power but in a finer climate, at Cam- bridge, in the United States. In 1850, Sir J. Herschel was prepared to declare it as being almost certain, since Lord Rosse's telescope had resolved, or rendered resolv- able, multitudes of nebulfe, that all the rest could be resolved by a farther increase of optical power, and the language might be made still stronger and more decisive, in consequence of what has been accomplished by that magnificent telescope since that date. The ncbuhe may now be confidently regarded as clusters of stars, and give evidence of order, combination, and law in the ex- treme boundary of that sphere of immeasurable magni- tude which constitutes the universe as knowable by us. It is worthy of being mentioned, as illustrative of order and law, that there are to be seen in the expanse of hea- ven, in many places two or more stars which are appa- rently near each other, and which have been shown to be mutually connected as part of one system. It not unfre- qucntly hapj)ens that a centre of light, wliicli appears as only one star to the naked eye, is turned into two or more stars by a telescope of very ordinary power. Sometimes the relation is merely optical, and not real, that is, stars 398 ORDER OF THE MOVEMENTS at a great distance from each other may seem near, "be- cause though the one be far behind the other, they lie nearly in the same line of vision to the eye. But the number of double stars in the heavens, being about 6000 in all, is far too numerous to be referred to any such cause. Among these, according to a table published in 1849, 650 are known in which a change of position can be incontestably proved.* Besides it has been as- certained in regard to considerably more than 100 double stars, that they revolve about each other in regular or- bits. In some cases there is a smaller star joined to a large one, in other cases there are two or more stars of Fig. 7S. nearly equal size revolving round a common centre of gravity. The orbit in which these connected stars move is ascertained to be elliptical. These phenomena lead Sir J. Herschel unhesitatingly to declare the stars to be subject to the same dynamical laws, and obedient to the same power of gravitation, which govern our sys- * Humboldt's Cosmos, vol. Hi. p. 280, Ottc's Translation ; additions being made every year by the labours of Argelandor, Starve, &c. t Fio. 78. Binary star, that is, two stars revolving round a common centre. OF THE HEAVENLY BODIES. 399 teni. The period of revolution of some of these combined stars has been determined, and is found to vary in differ- ent binary and multiple systems from 30 to upwards of 700 years. We have thus glimpses opened up to us in the depths of the sky, not of planet revolving round sun, but of sun moving round sun.''-' In the solar system we have satellite rolling round planet, and planet around sun, and double, triple, and multiple stars revolving round each other, and thousands of millions of stars grouped together in a common system. In consequence of having ascertained, as is supposed, the distance of some of these binary stars from the earth, it is not difficult to calculate, with an a])proach to certaintv, what are the dimensions of their orbits. These combined stars seem to be at a mucli greater distance from each other than the farthest planet of our system is from the sun. The distance of the two stars of 61 Cygni from each other, is 44 times the distance of the sun from the earth. The distance of these double and triple suns from each other is thus greater than the distance of the planets from the sun, in nearly as high a proj^tortion as the distance of the jjlanets from the sun exceeds that of the satellites from their primaries. All this gives the appearance of a regulated order in the relative distance of satellite from ])lanet, of planet from sun, and of sun from sun, so as to allow them to move freely, each in its own s})liere, whether a wider or narrower. The region which we have been sru'vcying used to be called tliat of the fixed stars ; but it has been shewn tliat tlie language is inapplicable. Every star is in motion : • It Li most Interesting to notico that many of tlio double stars Imvo colours wlilcli are complementary the one of tlio other. The larger star Is commonly of a ruddy or orange tinge, and the smaller one appears blue or green. " No green or blue star of iitiy ilcrjiled hue,'' says Sir .1. Hrrscli-jl, "has over, wc believe, been noticed unassoclatod with a compunlun brighter than itself," 400 ORDER IN THE MOVEMENTS absolute rest is unknown in the material universe. Our sun, with its retinue of planets, is travelling through space at the rate of 422,000 miles a day, towards a point near the constellation of Hercules. The mind grows dizzy in contemplating such velocity, but everything, meanwhile, is as stable as if all were at rest. It is evident that arrangements have been made to produce equilibrium among powers, each of which, acting alone, might work only destruction, and stability among objects which are never for one instant at rest. Even before the construction of Lord Kosse's telescope, it was thought that astronomers had sounded space to nearly 500 times the distance of Sirius, that is, ten thou- sand billions of miles. " Hence it seems as if, were the world island, in which our system is placed, viewed from the cluster in the hand of Perseus, it would probably appear as an assemblage of telescopic stars, ranged behind each other in boundless perspective ; from that of An- dromeda, it would diminish to a milky way, or pure nebulosity." It may be asserted, without any risk of contradiction, that nowhere within this wide knowable space, do we discover even the semblance of chance, con- fusion, lawlessness, or oversight. Nay, it may now be most confidently affirmed, that nowhere within this ex- tensive region, or in the long ages opened up to us by the time which light requires to travel from different stars, do we discover any traces of a chaos now existing, or ever having existed, or of worlds being formed by na- tural law, or of worlds only half formed or in the course of formation, or of any object overlooked, or out of place, or not in harmony with all the rest. As far as the tele- scope can carry our vision, or enable thought to carry out its calculations, Ave find all the bodies already formed, already in harmony, moving on in their spheres as if per- OF THE HEAVENLY BODIES. 401 forming some great and good office, and all so perfect, that our feelings are in harmony with the declaration of their Maker, when He is represented as proclaiming them " to be all very good." SECT. II. SPECIAL ADJUSTME>rTS ^"EEDED IN ORDER TO THE HARMONY OF COSMICAL BODIES. It is veiy manifest that every one part of the visible universe is intimately connected with every otlier. There are certain agents which seem to operate through the whole of it ; — there is gravitation attracting all the bodies to each other ; there is light flowing from mil- lions of luminaries ; there is heat radiating everywhere from the warmer to the colder regions ; there is probably, also, a universally diffused ether ; and possibly, also, Bome others of no less extensive influence, such as elec- tricity and magnetism. We are now to shew that all these require an adjustment in order to their beneficial operation. First, Gravitation. — The planets move in nearly cir- cular orbits round the sun, and the satelhtes round their primaries, and binary and multiple stars round each other, in consequence of the balanced adjustment of the velocity of the moving body and the central attractive force. Without a nice adaptation of the one to the other, two u})positc but equally deleterious results might have fullowed. Had the velocity been beyond its proper proportion, the body would have rushed away in a hyperbolic curve into space, to run the risk of collision with other bodies, and certainly to derange every other well-arranged system into wliich it might intrude. On the ^ther hand, liad the centripetal force been in excess, the separate existence of the bodies would have been lost 402 SPECIAL ADJUSTMENTS NEEDED IN ORDER in a mutual collapse and embrace, which must have de- stroyed every existing arrangement upon their surface. In a calculation of probability in a previous section, (pp. 48-50,) we have referred to two circumstances as needful to the stability of the mundane system : first, that the planets have a motion round the sun in the same di- rection ; and have orbits with very Httle and scarcely-vary- ing eccentricity, in planes with very moderate differences of inclination. There are conditions absolutely necessary to the continuance of the system ; — as the invariability of the major axis of the orbits of the planets, proved by lengthened investigations, in which the highest powers of the infinitesimal calculus were employed, by the most distinguished mathematicians of the latter half of last century ; as the long periodic change of the eccentricity of Jupiter and Saturn, which together amount to nearly a thousandth part of the mass of the sun, and which might have deranged the whole system under a different arrangement ; and there is the farther circumstance, that the planetary revolutions have among each other no com- mon measure. Change any one of these essential condi- tions, and the issue, sooner or later, would be a fearful conflict, in wliich every existing cosmical arrangement, with the planetary inhabitants, such as animals and plants, would inevitably be destroyed. But here we must allude to the attempt which has been made to turn aside the force of this argument, by a scheme of ingenious cosmogony suggested by Laplace. According to this hypothesis, the whole solar system has been formed out of floating matter rotating round an axis, and which, being at first greatly heated, has, in the process of coohng and condensation, given off the planets one by one, beginning with the outer ;, which planets, again, being thrown off in the form of rings, have, TO THE HARMONY OF COSMICAL BODIES, 403 in their condensation, given oif the satellites. We do not mean to enter upon a minute examination of this hypo'thesis. It was connected with, and received much of its support from, the supposed existence of unformed nebulous matter floating in space. Lord Rosse's telescope has dispelled these clouds, and the theories, light as clouds, which were built on them. ■••'•■ It may be acknow- ledged that there are some of the peculiar phenomena of planetar)^ movements which can thus be accounted for. But there are other facts beyond its power to explain, as that the satellites of Uranus should move in a direction opposite to that of all the other planetary bodies. " The satellites," says Professor Nichol, an ardent supporter of the hypothesis, " present farther a curious anomaly, or ratlier peculiarity. So far as we know, they all rotate on their axis, like our moon, in the exact period of a revolution in their orbits. This mode of rotation is evi- dently that of the original ring, but why the satellites have preserved that period is a my8tery."f This theory has been subjected to a searching examination by Sir J. Herschel. " If," says he, " it is to be regarded as de- monstrated truth, or as receiving the smallest support from any observed numerical relations which actually hold good among the elements of the planetary orbits, I beg leave to demur. Assuredly, it receives no support from the observation of the effects of sidereal aij;i]:rei2;a- • Some may urge that the hypothesis has heen corroborated by certain experiments of Plat<^'au as to the phenomena of a free liquid mass withdrawn from the action of gravity. In upcaklnj.' of the divi-ion of li(|iild masses into parts, I'latcau had coinparcd tlio iiiinuto maJUies to Bat< llitos; but In a subsiquont paper he corrects the iiiisappreliensions to which hU language had (riven rise, as if it favoured Laplace's cosino(,'ony. "It Is clear," ho say^ "that this mode of formation Is entirely foreign to Laplace's Cosmogenlc Ilypotlie- rU; therefore, wo have no Idea of deducing from this little experiment, which only ro- fein to the fffecUi of moletyiUar atlraetlon, and not to tlmso of gravitation, any ar(,'umcnt In favour of till! hypotlieclH in (lucstlou, au hypothesis which, in other respects, we do not ftilopL" — Taylor's Scientific Memoirs vol. v. t Planetary System, p. 241. 404 SPECIAL ADJUSTMENTS NEEDED IN ORDER tion, as exemplified in the formation of globular and elliptic clusters, supposing them to have resulted from such aggregation. For we see this cause, working out in thousands of instances, to have resulted, not in the formation of a single large central body, surrounded by a few smaller attendants, disposed in one plane around it, but in systems of infinitely greater complexity, con- sisting of multitudes of nearly equal luminaries, grouped together in a solid elliptic or globular form. So far, then, as any conclusion from our observations of nebulae can go, the result of agglomerative tendencies may, in- deed, be the formation of families of stars of a general and very striking character, but we see nothing to lead us to presume its farther result to be the surrounding of those stars with planetary attendants."* But let us admit, for argument's sake, the truth of this hypothesis, and we still urge that numberless adaptations, and these of a very remarkable description, are needed in order to admit of this loose floating matter being formed into the harmonious and beneficent results which fall * Opening Address, British Association, 1845. There follows a severe criticism of the pretended verification of that hypothesis hy M. Comte, which had been quoted with approbation bj' the author of the Vestiges of Creation, and by J. S. Mill iu his Logic. "If, in pursuit of this idea, we And the author first computing the time of rotation the sun must have had about its axis, so that a planet situate on its surface, and forming part of it, should not press on that surface, and should therefore be in a state of indif- ference as to its adhesion or detachment; if we find him, in this computation, throwing overboard, as troublesome, all those essential considerations of the law of cooling, the change of si)heroidal form, the internal distribution of density, the probable non-circula- tion of the internal and external shells in the same periodic time, on which alone it is possible to execute such a calculation correctly, and avowedly, as a short cut to a result, using, as the basis of his calculation, ' the elementary Huygenian theorems for the evaluation of centiifugal forces in combination with the law of gravitation,' — a combina- tion which, I need not explain to those who have read the first book of Newton, leads direct to Kepler's law ; and if we find him then gr.avely turning round upon us, and ad- ducing the coincidence of the resulting periods, compared with the distances of the plan- ets, with this law of Kepler, as being the numerical verification In question ;— where, I would ask, is there a student to be found, who has graduated as a Senior Optimo in this University, who will not at once lay his finger on the fallacy of such an argument, and declare it a vicious circle ?" &c. TO THE HARMONY OF COSMICAL BODIES. 405 under our notice on the earth, and which may he presumed to exist also in the other planets. Whence, for example, the striking adai^tation of the gravitating, chemical, gal- vanic, and electric powers to each other ? Whence the plants and animals which cover the face of the earth ? Whence animal instincts and the human soul ? Whence the correspondence between all these, and the atmosphere, and the light of the sun ? All this is wonderful on any system, but becomes vastly more incomprehensible when it is supposed that it originated in certain nebulous matter. The cosmogony referred to has never been car- ried out into details ; but if it had, we could have taken these up, and have proved that every one of them implies an adjustment. But dealing with it in its present vague form, it may be maintained that either the properties of this cosmical matter must have been such as in their own nature to imply a designing mind in the formation of them, or adjustments must have been made in order to their beneficent 02:)eration ; and on either supposition we have evidence of intelligence, and the hypothesis leaves the theistic argument where it found it. We go on to mention another beautiful arrangement which should be regarded as equally striking, whether we adopt or reject the hypothesis of Laplace. In the annual motion of the earth round the sun, its axis is in- clined from the perpendicular to its orbit at an angle of twenty-three degrees, and remains constantly parallel to tjiis direction. By this arrangement the changes of temj)erature on the earth's surface, and of the seasons, are produced. Had the axis of the earth, instead of being so inclined, been perpendicular to the plane of its orbit, as is the case in Jupiter, tlie sun would always have l)een vertical to the same line of places, the equatorial regions would have been parched by the heat, while the regions 406 SPECIAL ADJUSTMENTS NEEDED IN ORDER called teemprate in the present an^angement, would have been consigned to utter desolation. By the existing dis- position, the various parts of the earth are brought more fully under the solar influence, and we have all the de- lightful and beneficent effects which flow from the variety of climates. Again, the earth is nearer the sun at one season "than at another, and without some counteracting influence there would be an inconvenient increase both of the cold of winter and the heat of summer in the southern hemi- sphere, and the climates of the two hemispheres would be rendered altogether unlike each other. But any injury which might arise from this cause is made to disappear chiefly by means of the circumstance that the point of the earth's orbit which is nearest the sun is that over which it moves with the greatest speed. " It follows," says Poisson, "from the theory of Lambert, that the quantity of heat which is conveyed by the sun to the earth, is the same during the passage from the vernal to the autumnal equinox, as in returning from the latter to the former. The much longer time which the sun takes in the first part of his course is exactly compensated by its proportionably greater distance, and the quantities of heat which is conveyed to the earth is the same, whether in the one hemisphere or in the other, north or south."* Second, The Universal Difusion of Light. — Under this head we are called first to admire the wisdom of the arrangement by which a luminous body is placed in the centre of a solar system ; there being no physical ne- cessity, so far as we can discover, for such a disposition. Some astronomers have supposed (it has not been con- firmed by later investigation) that there are binary and multiple stars moving round central bodies which are * Hnmboldt'a Cosmos, vol. iv. p, 460. TO THE HARMONY OF COSMICAL BODIES. 407 not luminous ; it is evident that if our earth had been made to circle round such a body, or round a body simi- lar in constitution to itself, most of the living objects upon its surface would have become extinct. There is an evident harmony between the force or amount of light coming from the sun and the organism of plants and animals, for the life of both of which light, and this in a certain measure, is requisite. Had the light been much stronger than it is, it would have dazzled and blinded the eyes of animals, and stimulated to an exces- sive extent the growth of certain plants, while it would have utterly destroyed others. On the other hand, a diminution to any great extent of the luminiferous power of the sun would have imparted to our earth a dull and murky appearance, and have rendered it impossible for the plants of the earth, deprived of their needful stimulus, to subsist. If our earth, with its present vegetable cover- ing and animal tenants, had been as far removed from the sun as Uranus or Neptune, or even Jupiter, it is certain that a large portion of the species of living beings would long before this have ceased to exist. Taking the inten- sity of light upon the earth as one, the proj)ortions in the other planets will be as follows : — Mercury, . 6-G74. Jupitor, . . 0-036. Venus, . , . 1-911. Saturn, . . . 0011. Mars, . . . 0-431. Uranus, . . o-on.\ Pallas, . , . 0-130. Neptune, . . 0-001.* It is very evident that the earth could not have been placed in the room of any one of the other planets with- out endangering the existence of the greater number of the organized oljjects upon its surface. It may also be menti(jned here that there is a beautiful harmony insti- tuted between light and the gaseous envelope surround- ♦ Co8iuo«, Vol. Iv. i>. 401 408 SPECIAL ADJUSTMENTS NEEDED IN OEDER ing our earth whereby the sun's rays are diffused through the atmosphere, and are reflected upon us from every point of the concave heavens, in the infinitely varied hues of sky and cloud, instead of all streaming with burn- ing power from the sun alone, and leaving the rest of the hemisphere black as if it had been clothed in mourning attire. It is also worthy of being noticed, that in consequence of the comj)aratively small eccentricity of its orbit, much the same quantity of light falls upon the earth at all times. In this respect it may be compared with some of the other planets. While the earth, in periheHon, is 1'034, it is in apheUon O'DGT. Mercury, .... 10'58, .... 4-59. Mars, 0-52, 0-36. Juno, 0-25, 0-09. If the earth's eccentricity had been as great as that of Mercury or Juno, it is certain that not a few of our most useful and beautiful plants would have altogether disap- peared, or rather could never have existed. Tliirdly, The Universal Diffusion of Heat. — There is need of a number of harmonious adjustments in order to the beneficent operation of this agent so powerful for good but also for evil. It will be readily acknowledged that there must be a uniform temperature on the surface of the ground in order to the continuance of organized beings upon it. We know, as a matter of fact, that the earth's surface has had much the same temperature throughout histori- cal ages. The paintings and inscriptions on the monu- ments of Egypt shew that in that country much the same plants were cultivated, and that they riiDcned about the same season between 3000 and 4000 years ago, in the ages of the Pharaohs, as at this day. The plants of I TO THE HARMONY OF COSMICAL BODIES. 409 Canaan at the time of Moses and Joshua were not dif- ferent from what they are now. But the sustaining of this equable temperature depends on a combination of circumstances. First, there arc various sources of heat, and, in particular, there is the internal heat of the earth, which is known to be much greater than that of the ex- terior, and increasing as we go farther down, and there are the beams of the sun daily taking the circuit of the earth. Were these influences operating alone, the temperature of the earth's surface would soon be in- conveniently or rather destructively heated. But to counterbalance them, we have the earth's surface and its atmosphere radiating heat into the circumambient re- gions of space, which are ascertained to have a very low temperature, being lower than the freezing point of mercury. Our earth has thus, on the one hand, power- ful fires to heat it, and, on the other hand, an extensive reservoir of cold to keep it cool ; its surface is warmed by the internal heat, and by the heat of the sun ; and its temperature being thus rendered higher than that of the vault of heaven, it is ever radiating heat towards the re- gions of space according to the beautiful law of the universe, whereby all things tend towards an equilibrium. The uniform temperature of the earth from year to year, and from age to age, necessary to the continuance of the races of plants and animals, is sustained by the harmoni- ous adjustment of agents which seem to be distinct from, and independent of, each other, except in the original collocation of all things. An increase in the internal heat, or in the heat streaming from the sun, would speedily scorch the ground, and burn up tlie i)lants which grow ujjoii it. The same dire effects would fol- low, were the cool celestial regions not ready to receive the heat from the sun-warmed face of our eartli and al- ls 410 SPECIAL ADJUSTMENTS NEEDED IN OKDEK mosphere. On the other hand, were there not sources of heat within or without, the temperature of the earth would speedily sink below zero, and the whole globe be as much ice-bound as the north or south poles. It is to be remembered that the temperature of the ce- lestial regions is dependent, if not in whole, at least in part, on the temperature of the innumerable bodies which move in them. We are thus led to see that we are de- pendent for our continued existence, and our everyday comforts at home and abroad, on the disposition through millions of years of millions of bodies, removed from us milhons of miles. On the earth we are dependent for our very artificial fires, and for the mechanical power which can be gene- rated by them, upon influences which have descended from heaven in ages long past. We are using coal formed of vegetables fostered in former geological eras by the sun's rays. Allusion is made to these and to some other beneficial efiects of the solar rays in the fol- lowing passage from Sir John Herschel's Treatise on Astronomy : — " By the vivifying action of the sun's rays, vegetables are enabled to draw support from inorganic matter, and become in their turn the support of animals and of man, and the sources of those great deposits of dynamical efficiency which are laid up for human use in our coal strata. By them the waters of the sea are made to circulate in vapours through the air, and irrigate the land, producing springs and rivers. By them are pro- duced all disturbances of the chemical equilibrium of the elements of nature which, by a series of compositions and decom2)ositions, give rise to new products, and originate a transfer of materials." The far-reaching truth hero enunciated has opened the way to experiments, calculations, and speculations. TO THE HARMONY OF COSMICAL BODIES. 411 ■which all tend to shew how intimately connected every- one part of the visible universe is with every other. " We must look, then, to the sun," says Professor W. Thomson, " as the source from which the mechanical energy of all the motions and heat of living creatures, and all the motion, heat, and life derived from fires and artificial flames, is supplied. Tlie natural motions of air and water derive their energy partly, no doubt, from the sun's heat, but partly also from the earth's rotatory motion, and the relative motions and mutual forces between the earth, moon, and sun. If we except the heat derivable from the combustion of native sulphur and of meteoric iron, every kind of motion (heat and light included) that takes place naturally, or that can be called into existence through man's directing powers on this earth, derives its mechani- cal energy either from the sun's heat, or from motions and forces among bodies of the solar system." Such results having been attained in regard to the source of the heat and mechanical energy called forth on the earth, the question is started. Whence does the sun get the heat and light which he sheds ? There are insu- perable scientific difficulties in the way of supposing that the sun is a heated body losing heat, or that the sun is a great fire emitting heat due to chemical action ; and it has been surmised that " the sun's heat is probably due to friction in his atmosphere between his surface and a vortex of vapours, fed externally by the evaporation of small planets in a surrounding region of very high tem- ])('rature, whicli they reach by gradual spiral paths, and lulling inwards, in torrents of meteoric rain, form the luminous atmosphere of intense resistance to his sur- face."» • See ProfoMor W. Thomson'B I'oper In Trans, of Uoyal Society of Edin., 1854, and abstract of Karno In Edln. Now Pbll. Jour., January, 1855. 412 SPECIAL ADJUSTMENTS NEEDED IN ORDER Fotirthly, Indications of some other Universally Ope- rative Agents. Possibly all those we have been consi- dering and those Ave are now to contemplate, may be modifications of one and the same force : this is a favourite idea of not a few living men of the very highest scientific eminence, and it may be granted without affect- ing our argument. For if there be only one force, what a variety of adjustments must have been made in order to its producing such a number of results, so different from each other and so beneficent in their character ! Our conclusion follows equally from the admission of a number of forces suited to each other, or one force with an infinite number of adjusted collocations. But at the present stage of science, we are not entitled to say that all the forces of nature are one ; they present themselves to us as diverse, but all correlated, and capable of excit- ing each ofher. Meanwhile, we must look at them in the forms which they assume, and besides those which have been already before us, there are the magnetic and chemi- cal powers. It has been ascertained that there are periodical varia- tions in the magnetic forces on the earth depending on the solar day and the time of the year, and pointing .to the sun as the cause. It has also been discovered that there is a variation in the direction of the magnetic needle, going through all its changes exactly in each lunar day. " It would seem, therefore, that some of the curious phenomena of magnetism, which have hitherto been regarded as strictly terrestrial, are really due to solar and lunar as much as terrestrial magnetism.*" It has also been supposed that there is a connexion be- tween the period of the recurrence of the sun's spots and * President's (Mr. Hopkins) Address to British Association, 1853. TO THE HARMONY OF COSMICAL BODIES. 413 the period of the variation of magnetism on the earth's surface. 'The maxima of the sun's spots occurred m 1828, 1837, and 1848, the minima in 1833 and 1843; and it has been shown that the cycle of the variations in the earth's magnetic intensity is also about ten years, and bears a relation to the other cycle. Tliese discoveries open up curious glimpses of relations between things on the earth and things in the sky, such as men have not been inclined to beHeve in since science expelled astrology from human credence. We know further, that in the sun's rays there is a che- mical (actinic) as well as a luminiferous and calorific potency. These principles have each, in its own way, an influence on the germination and growth of the plant; and it is affirmed that all are in harmony with the seasons, and that each is strongest relatively at the time when most needed for the fvmction which it has to dis- charge in fostering the vegetable. Actinism is needed in order to tlie healthful germination of seed ; light is required to excite the plant to decompose carbonic acid; and caloric is necessary in order to develop and carry out the reproductive energies of the plant. "It is now," says Mr. Hunt, " an ascertained fact, that the solar, beam, during sjjring, contains a large amount of actinic principle, so necessary at that season for the germination of seeds and the development of buds. In sunnner, there is a large i)roportion of the hght-giving principle neces- sary to the formation of the wooden parts of plants. As autumn ajjproaches, the calorific or heat-giving ])rincip]es of the solar rays increase. This is necessary to liarden the woody i)art8 and i)repare them for the ajjproach of winter. It is thus that the proportions are changed with the seasons, and thus that vegetation is germinated, grown, and lianh'ucd by tli<'iii. We liave these state- 414 SPECIAL ADJUSTMENTS NEEDED IN OEDER ments on the authority of Mr. Hunt.* It is affirmed that every flower has its own .peculiar power in reference to heat, and that different plants take the different tem- peratures needed in order to their health, by reason of their different colours, which also determine the relative amount of dew deposited on the leaves. Fifthly, Traces of an aU-2Jervading Ether. The ex- istence of such a medium between the various cosmical bodies had long been suspected, and has now been estab- lished to the satisfaction of most scientific men. The resistance offered by it to the comet of Encke is the cause, it is believed, of the acceleration of the period of the revolution of that body, by causing it to fall nearer the sun. The acceleration is appreciable, being about two days in each revolution, which occupies about 3fV years, and it has been observed during a number of revolutions. But we know too little of the nature of this ether to admit of its being turned to much use in such a treatise. It may be legitimately argued, however, that if Hght — according to the prevailing theory in the present day — consists in vibrations in an ether, we must call in an important class of adaptations, the absence or alteration of any one of which would disturb the economy of the universe. The three rays, the violet, the yellow, and the red, must each have ether waves of different lengths ; and they must each make a different number of vibrations in a second, upon which circumstance the character of the coloured rays depends. The number of vibrations in the second is approximately as folows : — Violet, 699 billions. Yellow, 535 billions. Red, 477 billions. It needs no lengthened statement to show how liable * Uepoit on Chemical Action of Solar Radiations, British Association, 1850. We are by no means at the bottom of this subject. Farther investigation is evidently needed in order to put us in possession of the exact facts, and we are not yet within sight of the rationale of them. TO THE HARMONY OF COSMICAL BODIES. 415 such a complicated system is to go wrong, and how nice must be the continued adjustments so as to admit of our distino-uishino; stars and the colours of stars, so distant that light must require thousands of years to travel from them to us. For, on looking abroad on the face of the sk)', we cannot be said to be looking on the stars as they now exist, but on these stars as they existed many years, it may be thousands of years ago. We have per- fect confidence that there is no deception in all this, but in order to our trust being well founded, it is needful to suppose, if there be any truth in the prevailing scientific theory, that the ether has retained its laws and colloca- tions through both immeasurable ages of time and regions of space. Before closing this subject, we must refer to a most important class of facts, and speculations founded upon them, which have come into great prominence in the present day. The calculations of Lagrange and Laplace in regard to the stability of the solar system, (see p. 390,) proceeded on assumptions which later science has shewn not to be warranted. In particular, they pre-supposed that the planets moved in vacuo. But the prevalent opinion at this stage of advancing science is, that they move in an ether, the effect of which must be to lessen the velocity, and bring all the planetary bodies nearer and nearer the sun. The influence thus exercised in a brief period must be very small, but acting constantly, as it does, it must, in the course of ages, produce appre- ciable effects, and tend to break up tlie solar system.* Other facts, not reconcilable with absohite stability • The demonstration of the French mathematicians proceeded on tlic fiirlhor assump- tion that the planctn are solid throuRhout, and not fluid. But our earth, whatever may be the ca'c with the other planets, has the largest i)ort|on of Its surface covered with wat<'r« evir a:;ltated hy tides jiroduecd by the (;iavllatli)n of the moon. Now, It Is well known that when there Ifl water In a boat, the motion of the boat Is retarded by the agl- 416 SPECIAL ADJUSTMENTS NEEDED IN ORDER have come into %aew. Sir J. Herschel says that the breaking up of the Milky Way affords proof that it can- not last for ever, and equally bears witness that its past duration cannot be admitted to be infinite. Certain very important conclusions, tending in the same direction, have been established on following out the modern doctrine in regard to heat. Heat is now regarded as, if not identical with mechanical power, at least the means of producing it. As has been already stated, we are at present taking advantage of the mecha- nical energy excited on our earth, and laid up in store for us during the age of the coal formation. As this dynamical agency is being dissipated and wasted, we have here another disturbing element. The following are the conclusions drawn by Professor W. Thomson, who has deeply studied this subject : — " I. There is at present in the material world a universal tendency to the dissipations of mechanical energy. II. Any restoration of mechanical energy without more than equivalent dis- sipation is impossible in inanimate material processes, and is probably never affected by means of organized matter, either endowed with vegetable life, or subjected to the will of an animated creature. III. Within a finite period of time past, the earth must have been, and within a finite period of time to come, the earth must again be unfit for the habitation of man, as at present constituted, unless operations have been, or are to be, performed which are impossible under the laws to which the known operations going on at present in the mate- rial world are subject."* All this does not in the least detract from the skiU tation of the water; and on the same principle (a sciontlflc friend assures us) the tidal ugitation of the waters on the surface of the earth exercises a disturbing iuHuence on the movements of the earth in its orbit. Can any counteracting power be detected? + Transactions of Royal Society of Edinburgh, 1SS2. TO THE HARMONY OF COSMICAL BODIES. 417 displayed in those wonderful adjustments and counter- poises which were brought to light by the analytic dex- terity of the French mathematicians ; but it brings into view an overlooked set of agencies which must, in the course of ages, change the present system of things, provided always that they are not corrected by some well-adjusted counterbalancing arrangements. Professor Thompson says that there is not in nature any counter- acting agency. Without dogmatizing on so difficult a subject, it may be confidently asserted that science at its present stage cannot point out any means of restoring the lost energy. Even though it could be restored by natural means beyond the ken of man, it must be in con- sequence of a wonderful adjustment planned by intelli- gence. In either case, we are made to feel the depen- dence of all physical nature upon a higher power either to keep things in their present stable condition, or, in the event of some great change, such as seems not ob- scurely pointed to in the Word of God, to render that change beneficent. Doubtless the world is stable, (for " the earth abideth forever,") but it is by means of forces, each of which would make it very unstable, and which are made to produce stability by counteracting each other, so that there is a truth in that part of the thcogony of Hcsiud which represents Eros, the healer of divisions, as the world-forming principle. All this balancing is fitted, we should say intended, to carry up our minds to Him who holds the balances in His hands. Our confi- dence in the permanence of things must be made to rest, after all, on the purposes of a God wlio has ordained all things from the beginning, and who, when He changes any existing state of things, changes thciu in the deve- lopment of one ami I he same mighty |ilan. We are now in circumstances to estimate the amount 418 SPECIAL ADAPTATIONS IN ORDER of truth in a statement of Paley, whicli has been quoted with approbation by others, — " My opinion of astronomy," says he, " has all along been that it is not the best medium through which to prove the agency of an intelli- gent Creator ; but that this being proved, it shews beyond all other sciences the magnificence of his 02:)erations,"* Now, it may be admitted that astronomy does not dis- play so many cases of special adjustment as the animal kingdom, so beautifully illustrated by Paley. The reasons are not difficult to find : First, we do not know so much of celestial bodies as of objects on the surface of the earth ; we know little or nothing of the internal structure of the planets ; we know absolutely nothing of the composition of the sun or stars ; we do not know for certain whether any one of them is inhabited ; and so we cannot expect to be able to unfold such adaptations among them as among the objects with which we are familiar. Then, secondly, and more especially, there is no necessity for such special adaptation in the case of inorganic bodies as is required for living bodies, and more particularly for animals requiring provision to be made not only for their existence, but for their comfort. It will be found as a general rule, that we discover the clearest examples of special adaptation where our knowledge is most extensive and minute, and that they are more abundant where we see they are most required, in the frames of organized existences, especially of animated beings capable of plea- sure and pain, and the most abundant of all in the frame of man, the being who needs the greatest number and complication of organs to enable him to fufill his high destiny. But it is satisfactory to observe, that we are able to detect a number of striking examples of special adaptation among the celestial bodies in general, and the * Paley's Natural Theology, chap. xxii. TO THE HARMONY OF COSMICAL BODIES. 419 planetary bodies in iiarticular, and it is an instructive cir- cumstance, that in consequence of the advance of know- ledge, we are able to unfold a greater number than could be developed in the days of Paley. There is no just ground, then, for the scoffing remark of the haughty and eccentric Frenchman, (who denies that he is an atheist, seeing that he adores himself and has set up a formal worship of his system,) that the heavens cannot now be appealed to as a proof of the existence of Deity, or for the inference dra\vn by him, that the time will speedily arrive when organized objects will be in the same condition ; for while, for the reasons stated, animals and plants must ever furnish the most striking examples of design, it is still true that " the heavens declare THE GLORY OF GOD, AND THE FIRMAMENT SHOWETH HIS HANDIWORK." BOOK THIRD. THE INTERPRETATION OF THE FACTS. ■ ■ ♦ ■ ■ CHAPTER I. THE ARGUMENT EEOM COMBINED ORDER AND ADAPTATION. We are now to estimate the force of the influence of two streams, which we have hitherto been contemplating as flowing in parallel channels. The principle of Order has been scientifically ex- pounded only in modern times, and in regard to the animal and vegetable kingdoms only within these few years. But it existed from the creation of the world, and had been noticed in a general way since the creation of intelligent being. Science in its latest advances is simply coming up to, and explaining, the spontaneous suggestions of human thought, which as it muses upon the universe is at once struck with the model forms and correspondences which everywhere prevail. The late discoveries in regard to homotypes, homologies, and we may add homcBophytes, or parallel developments in ani- mal and vegetable structures, is but the scientific exposi- tion of what all along impressed intelligent observers, without their being able to give an account of it. Nor COMBIXED ORDER AND ADAPTATION. 421 are these remarkable facts of an isolated or exceptionable character ; on the contrary, they are merely striking ex- amples of what is universal, and they have their homo- types, analogues, homologues, and parallels, in every department of nature. The principle of Special Adaptation, or that of par- ticular conformity to the position of the object and func- tion of the organ, has also been noticed all along by minds addicted to reflection. Socrates is represented by Xeno- phon as delighting to dwell upon it. So strong, indeed, was this tendency in the ancient world, and in the middle ages, that Bacon felt himself called on to remove the inquiry from physical science, where it hindered the dis- cover)^ of physical agents, to metaphysics, where it might have a legitimate scope. Bacon was right in saying, that the propensity to discover final cause had sometimes come in the way of the discovery of pliysical cause ; but he is altogether wrong in affirming that it is barren of results in scientific inquiry, for in certain departments of natural science, such as physiology and comparative anatomy, it is a most powerful instrument of discovery, and such eminent men as Cuvier and Sir Charles Bell delight to inform us that tliey have proceeded on the principle of final cause in all their researches. It is not difficult to discover the beauty and the ap- propriateness of both these principles. On the one hand, the mind discerns the need and ap- preciates the propriety of the princi])le of Order. Without some sucli governing principle, nature would be incom- prehensible by human intelligence, and this because of the very number and multiplicity of the objects of which it presents, each eager to catch our notice ; and the mind in trying to apprelniul tlicm would have felt itself lost, as in a forest throngh wliich there is no pathway, or as 422 THE ARGUMENT FROM in a vast storeliouso, where the seeds of every species of plant on the earth's surface, are mixed in hopeless con- fusion. By what means is it that man is enabled to ar- range into groups the objects by which he is surrounded, and thus acquire a scientific knowledge of them, and turn them to practical purposes ? Plainly, by reason of the circumstance that there are numberless points of resem- blance and correspondence between them. Scientific men have so long been familiar with this process that they are not impressed by it as they ought, and seldom do they inquire into the ground on which it proceeds. It is only when something new, such as the discovery of homologies in the animal kingdom, comes to light, that they are led to reflect on what has been too common to be sjiecially noticed. But if they but seriously reflect on the subject, they will find that it is because of the uni- versal prevalence of points of resemblance and corre- spondence that man is enabled to grasp the infinity of objects which fall under his view, into classes and sub- classes, which can be comprehended by the intellect, and treasured up in the memory. No doubt the mind has in itself a power of forming classes altogether independent of any special arrange- ment in order to aid it ; but such groupings, though they may at times help the memory, are of no intellectual or scientific value. But there are means in nature of guid- ing the mind to the formation of classes which have a deep and far-reaching significance. It is true, in an important sense, that classes are already formed for us in nature. Man will find it expedient, in all cases, to attend to these arrangements made to his hand, and he must attend to them, provided he represent his classification as a natural one. It may illustrate our general subject to show what are the distinctive marks COMBINED ORDER AND ADAPTATION. 423 of natural classes, that is, of classes having the sanction of nature. And first, we may take a classification wliicli is not of this description. It is conceivahlc that a person might arrange all animated beings according to their size. He might put all animals of a certain height in one class, and all animals below that in another class. Every- one sees how arbitrary, in short, how contrary to nature, such a distribution would be. It would often separate animals belonging to the very same species, while it would put in one confused group bird and fish, mammal and insect. And why, it may be asked, does the naturalist at once reject such a classification ? Perhaps it is answered, because he is seeking a natural arrangement. But this answer, though correct so far as it goes, does not go down to the depths of the subject, for we immediately ask. Is not the distinction of size a natural one ? He who would really sound the depths of this subject, and not skim over it, must be prepared to state what is the difference between an artificial and a natural classification. All natural classes will be found to have not merely one, but an aggregate of common attributes. It follows that, when objects are classified according to a natural arrangement, the possession of any one characteristic is a mark of a great many others. Thus, when an animal is described as a reptile, we know that its blood is cold, that its heart consists of three cavities, and that its young are produced from eggs ; and when we hear an animal called by the name of man)mal, we know not only (hat it sTickk'H its young, but that it breathes by lungs, that its Idood is warm, and that its heart consists of four com- partments. In short, when wo have fixed on a truly natural arrangement, the presence of any one character- istic becomes a sign of others, commonly of very many 424 THE AEGUMENT FROM others, at times of an inexhaustible number of others. The co-existence of these characteristics in one object, and their invariable co-existence in all objects possessing any one of them, is a clear evidence that such an arrangement has been purposely made. A class with such an aggregate of qualities as its ground, is said to be one of" Kinds." There are some valuable remarks on this subject in the Loo;ic of Mr. J. S. Mill. " There are some classes, the things contained in which differ from other tilings only in certain particulars, wliich can be numbered, while others differ in more than can be numbered, more than even we need ever expect to know. Some classes have little or nothing in common to characterize them by, except precisely what is connoted by the name ; white things, for example, are not distinguished by any com- mon properties except whiteness, or if they are it is only by such as are in some way dependent upon or connected with whiteness. But a hundred generations have not exhausted the common properties of animals or of plants, or of sulphur, or of phosphorus ; nor do we suppose them to be exhausted, but proceed to new observations and experiments, in the full confidence of discovering new properties, which were by no means imj^lied in those we previously knew. It aj^pears, therefore, that the pro- perties on which we ground our classes sometimes exhaust all that the class has in common, or contain it all by some mode of implication ; but in other instances, we make a selection of a few properties from among not only a greater number, but a number inexhaustible by us, and to which, as we know no bounds, they may, so far as we are concerned, be regarded as infinite."* We now see wherein lies the essential distinction be- tween an artificial and a natural class, and the superiority * Mill's Logic, B. 1. c. vii. 4 1 COMBINED ORDER AND ADAPTATION, 425 of the one to the other. In an artificial arrangement, we seize on a quality — ^not arbitrarily, it may be, but still for mere conyenience' sake — and our an-angement does not yield us any farther information on the subject. In a natural classification, on the other hand, we fix on qua- lities which are iuA^ariably accompanied with certain other qualities, and which are, therefore, signs of them. AU that an artificial class can do is to aid the memory, by having the innumerable objects put into a convenient number of groups. Even for this j^urpose a natural arransrement, if we can seize it, wdll be vastly more useful than an artificial one, as it will be found, in fact, that no artificial arrangement can embrace all the facts, and enable us to carry them about with us in convenient groups. But a natural classification does more tlian help the memory, it imparts positive knowledge, inas- much as one property is a sign of the presence of a vast number of others. The most fundamental of all groups in Natural History, that of species, is ahvays one of Kinds. It is formed on the principle that all the animals in- cluded in it might have proceeded from a common pa- rentage ; but all animals belonging to the same species are found to have a great many other points of resem- blance besides their belonging to one stock. The same is true, to a greater or less extent, of all other natural groups, such as genera, orders, and kingdoms. In all such natural classes, the presence of some one attri))ute is a means of informing us of the presence of others. Thus, the ])ower of speech is one of the characteristics of hunui- nity ; but tlicre are many others, so many others, tliat physical and meta])liysical science cannot be said to have fully exhausted tiiem, and the presence of the power of speech is a sign of all these otliers. A traveller has lost himself in a deej) forest, amidst wild birds and beasts, 426 • THE AEGUMENT FROM whose cries all raise within him feelings of alarm ; sud- denly he hears a human voice, and that sound at once announces that there is intelligence at hand, and pro- bably also a comjiassionate heart, and the power and disposition to aid him. All the marks of a natural class are significenf, in the same way, of an indefinite number of other attributes. This invariable collocation of characteristic qualities in certain objects, so that the one is a sign of all the rest, is a clear proof that classes do exist in nature — that is, that objects are gathered into classes. This, we doubt not, was at least one of the truths which led to the mystic doctrine of Plato about Ideas or Types, above individual things and prior to individual things, and in mediaeval times to the doctrine of Realism, according to which, universals or classes have an existence as well as indivi- duals. There is a great truth at the basis of these theories, now exploded, but entertained in former ages by some of the deepest thinkers which our world has pro- duced. This truth was not correctly seized, was very imperfectly, indeed, often very erroneously represented, but still it is deep in the constitution of things. All natural objects, and especially all organic objects, are fashioned according to type, and operate according to unchanging laws. The individuals all die, shewing how insignificant they are, whereas the genus and species survive. The flowers of last summer are all faded, but in the coming summer, other flowers will sjning forth to continue the same form. Amidst the flux and reflux of aU individual existences, the laws which they, obey are permanent. In particular, classes, genera, and species, liave as certain an existence in nature as the objects which are classified. There is no new thing under the sun. The modern 1 COMBINED ORDER AND ADAPTATION. 427 doctrine of organic correspondences is but the distinct articulation of what thinking minds have ever felt — but the scientific interpretation of the unconscious musings of deeper thinkers, as they have been gazing on the cryp- tic symbols of nature, ever since the time when inward reflection was awakened by outward objects. Nay, it is, after all, but the extension, into a new field, of the prin- ciples on which scientific classification has all along been restin"-. The facts on which the new doctrines are founded are the homotypes and homologues of the facts on which ordinary classification proceeds. The classifi- cation into genera and species proceeds on corresponden- ces among a vast number of individuals. The doctrine of homotypes takes its rise from the correspondences in many parts of the same individual. Homologues are corresponding members in different individuals. We may add that homceophytes are corresponding stages in the development of different organic kingdoms. So much, then, in regard to the fitness of the one principle — it enables mankind to make a practical and scientific use of the objects by which they are surrounded; and, as some one remarks, nature was made to be enjoyed by brutes, but to be contemplated by man. It is still more necessary that the other principle, that of Special Adai)tation, be attended to ; for if the comprehensibility and beauty of the universe depend on the one, the very existence of the objects in it, and especially of animated beings, depends on the other. And here it may be important to remark, that tlic principle of special aOxiptation assumes two distinct forms. So far as the efficient powers, the dynamical ener- gies, the active properties of matter, are coiucnMil, the adaptation consists in their adjustment so as to produce a general law, or it may \nt also an individual effect of a 428 THE ARGUMENT FROM beneficent cliaracter. It is tlius that the centripetal and centrifugal forces are adjusted to yield the harmonies of the planetary system ; thus that the relation between the earth's orbit and the sun are arranged to yield the seasons of the year. In organic bodies, again, where the law is one of type or structure, we find the special adap- tation taking a somewhat different form. We now meet not with an adjustment of forces to produce a law, but a modification of a general type, or a departure from it on one side or other, and this obviously to enable the part to execute its office. Under the first of these forms the adaptation is necessary in order to the very existence of general order ; under the second, it bends the general order to the accomplishment of special ends. It is in this second form that adaptation appears in the structure of animated beings. Not only the comfort of the animal, but its very continuance upon the earth, depends on every organ being made to serve its special function. And here it is satisfactory to find, that while attention is paid both to order and special end, the most uniform regard is had to the latter. There are cases, as we have seen, in which the general plan, if not sacrificed, is at least kept in abeyance, so that it is very difficult to detect it. It is of all pretensions the most. absurd, in certain naturalists to profess to be able to see the general homologies, which are often very obscure, and yet regret that they can never discover special modifications to serve a given end, which are often so very clear. It is satis- factory to find that the wcllbeing of the plant and the happiness of the animal are never sacrificed in following out the typical form. The general often gives way to the special, but the special never gives way to the gene- ral. It cannot be said of any animated being, that its individual comfort has been sacrificed in the attention COMBINED ORDER AND ADAPTATION. 429 paid to some general law or model shape. It is a cir- cumstance worthy of being noted, that the typical form is most clearly exhibited in the lower animals, whose wants and functions are fewest ; and that the principle of teleology is carried out to the farthest extent in animals higher in the scale, whose organism is the most compli- cated, and has the most numerous and varied functions to perform ; and, farthest of all, in man, whose frame is so fearfully and wonderfully made to enable it to become the fit instrument of tliat spiritual nature to which it is united. When we take an enlarged view of these two princi- ples, we shall find that they are not inconsistent Avith each other, but rather that they depend on eacli other. There is an adaptation necessary in order to those regu- lar successions of events and model forms which come so frequently before us. The regular flow or periodic re- currence of such phenomena as the tides, the seasons, is the result of arrangements many and varied. The forms assumed by j^lants and animals is evidently the contem- plated issue of a multitude of forces made to combine to this end.* On the other hand, the general order, in some * When the action of the combination of powers necessary to the development of an organ is interfered with, we have a iloiwiter. In monstrosities the principle of order is not accommodateitles do not produce pain, they wc not evils any more than un Irregularly-formed crystal Is. So far as they are the means of entailing suffering and humiliation airioug mankind, they carry us Into the profoundest of all mysteries (which we cannot hero discuss) — Die existence of evil. 430 THE AKGUMENT FROM cases, accomplislies very useful purposes; as when the mathematical law of the increment of the shell enables certain molluscs to ascend and descend the water at will • and when the spiral arrangement of the leaves and buds all round the axis exposes them equally to the light and to the air. In aU cases the general order is adapted to the intellect of those who are expected to contemplate it. Everything has, after all, a final cause. The general order pervading nature is just a final cause of a higher and more archetypal character. In the special principle, we have every organ suited to its function ; in the more general principle, we find all the objects in nature suited to man, who has to study and to use them. Professor Owen has declared, that his practical assistant found himself greatly aided, in setting up the bones of the skull, by proceeding on the principle that they were constructed on the vertebrate type. Lecturers on anatomy find their students following them much more readily when they expound the skeleton on the archetypal idea. It is only by proceeding on some such method that the nomen- clature of comparative anatomy can be retained by the memory. Without some such principle, there would require to be one set of names for the bones in man, another set for the bones in quadrupeds, and a third and a fourth set for the bones of birds and fishes. By the discovery of homologous parts running through all, it has been found possible to devise a common nomencla- ture, admitting of application to all vertebrate animals. But let it be observed, that it is not the unity of the nomenclature which gives the unity to nature, but it is the unity of nature which has given a unity to human science, and the nomenclature which science employs. These corresijondences are admirably fitted to make COMBINED ORDER AND ADAPTATION. 431 creation compreliensible by the human faciiltic?. The more obvious points of resemblance enable man to recog- nise the nature and end of the objects by which he is surrounded. The more fixed points allow him to arrange them into classes in due subordination. The repetition of parts permit of his at once taking an intelligent glance along the whole length, and over the whole frame, of the animal and plant. The answerable parts permit of his discovering unity among organs that serve very diverse purposes. The members with similar functions invite him to observe a universal final cause. The parallel de- velopment points to a unity of aiTangement in the forces by Avhich all these correspondences are produced. The prophetic system of geology entitles him to look on the earliest past as a foreshadowing of the future, and on the l^resent as the fulfilment of what has gone before. Before the time of Geoffroy St. Hilaire, the undeve- loped rudimentary organs were frequently thrown away as useless in the Museum of Comparative Anatomy in Paris. But it is rash, it is wrong to declare that any part of nature is useless. Geolfroy restored these organs, and thus led the way to grander generalizations of organic objects than had ever been formed before. We have now before us a sufficient final cause of typical forms. We may rise above a special adaptation of parts to an arche- typal adaptation of the whole to the constitution of intellectual beings. We have here a most beautiful cor- respondence between the laws of external nature and the laws ^)i' the mind, between the laws of thiugs and the laws of tliought.'-' While the special modifications or adapta- tions investigated so carefully by Cuvier, are intended to promote the wellljeing of the particular species ol" ani- mal, the archetypal j)hin investigated by Owen is fitted • Tills Id bo IntcrcAtlnga topic, that wc ore to dcvoto tli« next chnptcr to It 432 THE ARGUMENT FEOM to make tlie animal intelligible by the intelligent crea- tion. Owen has developed — to some extent perhaps un- consciously, but to a far greater extent consciously — a teleology of a higher order than Cuvier. Viewed in this light, the two principles, though evi- dently differing from each other in many respects, and requiring to be separately treated, come to be very much alike, may be seen to be analogous — that is, different organs fulfilling a similar function. The special adap- tation proceeds on a general principle of beneficence, and the general principle is an example of adaptation to a special end. There is a general plan in the purpose, and a purpose in the general plan. The teleology is a homology, and the homology is an example of teleology. There are some who prefer a somewhat different re- ligious interpretation of the model forms of nature. Order and law, they say, are the natural methods of the Divine procedure, the ways in which God's nature and character spontaneously exhibit themselves. We need seek, they say, no other explanation than this of the typical forms in heaven and earth, they are just the manifestation of the divine ideas. And, as to man's re- cognition and appreciation of these laws and models, it is to be accounted for by the circumstance that he was made in his Maker's image. We are indisposed to advance a single word against this view ; possibly it may be as true, as it is certainly striking and sublime. It is certainly a doctrine which cannot be disproven : we may venture to doubt whether it admits of absolute proof. Do we know so much of the Divine nature as, a priori, to be able to affirm with certainty, how that na- ture must manifest itself in creation ? There may even be presumption implied in declaring, in some cases, that the harmonies of nature are after the taste or character of COMBINED ORDER AND ADAPTATION. 433 God ; for example, that complementary colours are more beautiful to His eye, as they are to ours, when seen in collocation, than non-complementary colours. But while we cannot predicate much, a 2Jriori, of the character of God, there is much that we can affirm, a posteriori, of the character of man, of his intellectual aptitudes and his tastes. We do know that correlations among objects are needful in order to his being able scientifically to arrange them, and practically to use them, and that he has tastes implanted within him, which are gratified by objects without him ; for example, the ability to receive gratification from the complementary colours of animals and plants. We have here a firm ground to stand on, in reasoning from "what we know," and as there is a correspondence between man's constitution and the scenes in which he is placed, we cannot be wrong in inferring that God, by His nature and character, is led to accom- modate the external world created by Him, to the intel- lectual nature of man, also created by Him. There is sense, then, and this a sense as grand as it is true, in which we are justified in rei3resenting these types aa proceeding from the very ideas of God, from His eternal wisdom, imjjelled by His eternal love. Nay, we are inclined to think that as there are homologies among organic structures, so tliere may also be correspondences among spiritual natures, and that other intelligences, differing in many respects from man, may resemble him in this, that they also delight in these laws and patteras; while God, over all, may be conceived as rejoicing in all His works together. Ah taking this view, we are not inclined to admit tliat the doctrine of final cause has been set aside, or sliaken, or even damaged, Ijy late discoveries in natural history. It ia tnie that some of those engaged in making these dis- 10 434 THE AKGUMENT FROM coveries did not see their consistency with teleology. Oken, as a pantheist, admitted, so far as we 'Imow, no final cause into his system. Geoffroy St. Hilaire reckoned it presumptuous in man to discover any end designed by the Creator. Cuvier was led to reject the doctrine of the unity of the vertebrate skeleton, partly by the practical turn of his mind, partly by the fear that it would inter- fere with the doctrine of final cause. Some, we suspect, have supported the doctrine of a jjliysical uniformity of parts, because it seemed to deliver them from the ne- cessity of calling in a personal God to account for the economy of nature ; while not a few have regarded it with suspicion, because it seemed to be atheistic or pantheistic in its tendency. But amidst all these exhi- bitions of presumption and of fear, the doctrine of final cause stands as firm and as impregnable as ever, assail- able by no known fact, consistent with every established truth. Physiological research has, we admit, established a truth which cannot be reduced to final cause in the nar- row sense of the term, but that truth is not inconsistent with final cause — it is an illustration of a higher form of final cause. We blame Cuvier because he would not attend to the evidence which his own discoveries supplied in favor of unity of composition. Not being of a specu- lative turn of mind, he would attend, he said, to nothing but facts, and content himself with classifying them. But we must also blame Geofiroy St. Hilaire, when, after condemning Cuvier for narroAving the field of science, he professed to be incapable of discovering final cause, and bids us remain " historians of what is." ■-••■ Final cause is, to say the least of it, as certain as unity of comjDOsition. It is surely as certain that the eye was made to see, as • Vie, Travaux ct Doc. Scien. de Geoffroy St. Hilaire, par son Fils, p. 304. COMBINED ORDER AND ADAPTATION. 435 that it is the homologue of the whisker of a cat.* We give httle credit for sincerity to those who acknowledge that they have overwhehning evidence in favour of the former truth, but no convincing proof in behalf of the latter. Again, there are metaphysicians who think that they have undermined the whole doctrine. We must reserve to a separate section the examination of any plausible considerations which they can urge. Meanwhile, let it be observed that their objections proceed on principles which would undermine all other objective truth, and leave us only a series of connected mental processes. The principles by which they would set final cause aside have not half the evidence in their favour which the doctrine of final cause has. We are sorry to find an accom])lished and devout wTiter saying, " The argument from first or final cause wUl not bear the tests of modern metaphysi- cal inquirers. The most highly educated minds are above them, the uneducated cannot be made to comprehend them."f The modern metaphysical speculators who have rejected final cause, have great need to review their own principles when they are opposed to a truth so obvious and so supported by scientific research. The argument from final cause is one which the uneducated universally feel, though they are incapable of explicating it logically, or illustrating it scientifically. The educated can feel that they are above it only in so far as they are elevated by the intoxicating fumes of German specula- tion, which would make man beheve that he is a god, and that he creates from the stores of his own mind the final cause, which he simply discovers. Verily there are • In tlio animal body tlio following parts aro admitted to be nil homologous; — TiictUo C/or|)U»cli'(<, I'lurliilan bodicH, Suvlari bo'lloH, Muciparous ducts of flshes, Vibrissa} (whls- kerii) of cut and otliorn, tlir uyr, tlic car. t Jowclt on Eplxtlu to tbu Uomans; Natural Uellglon, p. 410. 436 THE ARGUMENT FROM metaphysicians whose heads have been so dizzied with the turnings and windings of their own cogitations, that realities swim before them and they cannot distinguish between them and phantoms. Living forever in a region of pure, or rather very impure and cloudy speculation, they do not, as the physical investigator is ever doing, meet with stringent facts to restrain and control them ; they have become utterly incapable of weighing ordinarj'' evidence, probable and moral ; they cannot see that the thoroughly established truths of inductive science are in the least degree more certain than the last spawned, a priori, theory of the universe ; nay, some of them (such as Hegel) are prepared to deny the doctrine of gravi- tation itself, because it will not fall in with their theory. No wonder that final cause cannot stand the tests of such inquirers, for these tests need themselves to be tested. As taking so enlarged a view of final cause, we have no objection to the general statement laid down by some eminent scientific men, that there are parts of the vege- table and animal frame which have no respect to the functions of the plant and animal. " There is yet an- other law," says De Candolle, "to be understood to enable us to judge properly respecting the nature of organs. In innumerable instances there appear forms similar to those which are connected with a definite function, but which do not fulfil that function, and nature, in these instances, as in the animal kingdom, seems to produce forms which are completely useless, merely for the sake of a harmonious and symmetrical structure. The ap- pearance of filaments with empty anthers in flowers which are altogether female, and of female parts in flowers wholly male, the structure of filaments in other forms where they resemble nectaries, the false nectaro- thecae in such orchidae as have no nectaries, these are COMBINED ORDER AND ADAPTATION. 437 all formations which can only be explained by the law of nature we are now illustrating." Professor Owen uses similar lano;uao;e : — " I think it will be obvious that the principle of final adaptation fails to satisfy all the conditions of the problem. That every .segment and al- most every bone which is present in the human hand and arm should exist in the fin of the whale, solely because it is assumed they were required in such number and collocation for the movement of that undivided and in- flexible paddle, squares as little with our idea of the simplest mode of effecting the purpose, as the reason which might be assigned for the greater number of bones in the cranium of the chick, viz., to allow the safe com- pression of the brain-case during the act of extrusion, squares with the requirements of that act."* And again, " The attempt to explain by the Cuvierian principles the facts of special homology on the hypothesis of the sub- servience of the parts so determined to similar ends in different animals — to say that the same or answerable bones occur in them because they have to perform simi- lar functions — involves many difficulties, and is opposed by numerous phenomena. We may admit that the multiplied points of ossification in the skull of the human foetus facilitate, and were designed to facilitate, child- birth ; yet something more than such a final pnrpose lies beneath the fact, that most of these osseous centres repre- sent permanently distinct bones in the cold-blooded ver- tebrates. The cranium of tlie bird, Avhich is composed in the adult of a single bone, is ossified from the same nund)er presents a constant evolution of 500 THEORIES OF CONTINENTAL PHILOSOPHERS AS TO nothing becoming something, and we have to add, of something falling back into nothing. In the unfolding of this theory, he represents God as attaining to consciousness in man, and the whole history of the human race as a succession of incarnations. At his death, which was occasioned by cholera, some of his pupils apotheosized him as the noblest of all the self-conscious developments of Deity. It is easy to see how he accounted for the harmonies which the mind discovers in the universe. To philoso- phize on nature, he says, is to rethink the grand thought of creation — it is to reproduce, from the depths of the soul, the creative ideas of nature. In a journey which he made to Paris, he was greatly entertained, as he discovered everywhere — in nature and in art, in man as an individual, and in man united in society — confirmations of his system, which widened, like vapours, to embrace all the agreements and disagreements in exist- ence. It might easily be shown that this ambitious and arrogant system de- stroys all personal! tj^ — that is, separate consciousness and will — in God, all personality in man, and that it is inconsistent with human responsi- bility, and the immortality of the soul as a separate existence. All this has been dwelt on by the schools which have set themselves in opposition to it in Germany. And this argument from consequences should have its weight, for any system which sets itself against these truths, cannot be supported by such evidence as they can adduce in their favour. Again, various gaps and inconsistencies have been pointed out in it, showing that it is not so solid a structure as it professes to be. But its fundamental error lies in this, that it denies the separate existence of individual things — of the subject on the one hand, and the object on the other. In pro- fessing to proceed according to the laws of thought, it begins with set- ting the clearest laws of thought at defiance, and must wander the more the farther it advances. It is acknowledged, even in Germany, to be a failure. It fails, in particular, to account for the correspondence between mind and matter regarded as separate existences. It should be added, that Herbart met these idealistic views of Kant, Fichte, Schelling, and Hegel, with great vigour by a realistic scheme, in which final causes once more have their proper place. But his realism is professedly a rational system erected on certain philosophic principles, which may be assailed equally with the grounds taken by those whom he opposes, and will not find much favour among persons in our country who have become imbued with the spirit recommended by Lord Bacon, and followed out, though with but imperfect success, by Locke and Reid. It is only by proceeding in the inductive method that we can expect fairly to unfold the subjective laws of mind on the one hand, and the objective laws of nature on the other, and then discover the relation between them. In the speculations of all these philosophers, notice is taken of a most RELATION OF LAWS OF NATURE TO INTELLIGENCE. 501 important class of facts, which have very much escaped the attention of British writers. But while we acknowledge this, we are convinced, at the same time, that the correct explanation has not been given by the conti- nental speculatists. In the days of Descartes and Spinoza, the questions discussed turned round the action of mind upon material objects, and the action of material objects upon mind. But from the time of Leibnitz, and still more from the time of Kant, a new set of questions came to be agi- tated in regard to the accordance between the laws of the mind within, and the harmonies of external nature without. Kant and Fichte referred this to the mind creating the order which it contemplated, Schelling and Hegel to the identity of subject and object, of the world within and the world without. But none of these hj'potheses meets the full flicts of the case, nor explains the whole phenomena. Leibnitz, indeed, had a glimpse of the truth, but failed to represent it fully and correctlj'. The facts admit of only one satisfactory explanation, and this an explanation in strict ac- cordance with the doctrine of final cause, and implying a specific plan on the part of an intelligent being. For mark, that we have, first, a set of internal facts. TVe have in the mind perceptions tlirougli the senses ; we have certain intelligent aptitudes, • such as the generalizing propensity, ever seeking to group the objects it meets with into classes, and causality, anticipating nature, and confidently looking for certain effects to follow agencies now in operation ; we have instincts and affections craving for external objects on which to lavish themselves ; and we have a sense of beauty, longing for scenes of loveli- ness and sublimity. Wo insist that these internal facts be not set aside, but that they be embraced and accounted for in any exi)lanation which may be offered. It will not do to refer them, with certain French and British writers, to sensations and impressions from without. They are evidently powers, instincts, affections, fundamental laws in the mind itself, making their own use of the inQuences wliich may come in from the external world. But, secondly, there is a set of external facts. As little are wo at liberty to overlook them. In denying them, we are, in the very act, discarding the dicta of consciousness, and the very constitutional principles of intel- ligence in the mind ; and after we have done so, there remains no ground on which wo can reason on this or on any other subject. Hero, in this world which we perceive, are bodies endowed witli wonderful properties ; are objects grouped into classes, and witli interesting correlations subsist- ing between them ; are events causally connected together ; and scenes of beauty and grandeur. All this must bo explained by a hypotliesis ade- quate to meet the case obviously- jirescnted, and no part of all this can be accounted for merely by the inward principles of the mind, except on the ground whidi would make these very principles delusive and a delusion. 502 THEORIES OF CONTINENTAL PHILOSOPHERS AS TO * "We have thus a series of facts in congruity with each other within the mind. "We have also a series of facts in beautiful harmony with each other without the mind. But we have more, there is an accordance be- tween the internal and external facts. "We have the perceptions of one 'sense confirmed by those of another sense. "We have instincts impelling to certain operations, and we find ourselves placed in a state of things in which these instincts are gratified, and in being so, perform acts necessary to our welfare and our very existence. "We have affections general and special, and we fell in with objects to call them forth, and on which to lavish them. "We proceed spontaneously to classify objects according to certain relations of shape, quantity, and proportion, and actually find them distributed into groups according to these very principles. "We anticipate that the same cause will ever produce the same effect, and find our expec- tations realized every waking hour of our existence. "We have assthetic tastes, and everywhere there are harmonious colours, and graceful forms, and lovely scenes to gratify them. As it is not the sound which produces the ear to receive it, as it is not the eye which creates the light that falls upon it, so it cannot be the outward harmonies which create the inward desire to discover them, and the capacity to observe them ; nor the internal faculties and feelings which create the outward harmonies. "We are ob- hged, if we would account for the whole phenomena, to account for both classes of facts, and the relation between them. This can only be done by supposing that one Intelligent Being instituted both series of facts and their mutual accordance. The facts round which tlie German philosophy has been moving, are thus seen to bring us back to the old doctrine of our British Theology. It is only by calling in a God who designs and exe- cutes, that we can fully or rationally account for facts, which we cannot deny without denying our intelligence. It thus appears that the doctrine of Final Cau.'^c, so far from being un- dermined or shaken by these speculations, is as secure as ever — nay, it stands forth with new illustrations and confirmations. We are brought back to what observant minds have noticed from the first, (though they had not always expressed it correctly.) a concurrence of independent agencies towards the production of a given end. Hegel is laying down an utterly mistaken doctrine when (not in words denying final cause) he speaks of the final cause of athing being the inward nature of a thing, or a thing following its inward nature ; final cause is the co-operation of a number of independent things to accomplish what is evidently an end. In particular, there is need of a correspondence of the external and inter- nal in order to our inward knowledge, and to our experience of the outwad world. The phenomenon cannot be explained by an internal order pro- jecting itself upon the external world ; for, as Herbart asks, if it be by some necessary form of the understanding that final cause is imposed on RELATION OF LAWS OF NATURE TO INTELLIGENCE. 503 things, how are we to account for tlie fact that we do not see the final cause in regard to every occurrence ? How is it, in particular, that we discover it only in those cases in which we notice a concurrence of agen- cies acting independently of the laws of thought within ourselves? All this can easily be accounted for on the supposition that it needs objective evidence to lead us to discover final cause; but is inexplicable if tlie pro- cess proceeds from a merely subjective principle. But, without pressing thus difiBculty, we plant ourselves on ground from which we can never be dislodged, when we maintain that the outward is real and that the inward is real, and that there is proof of plan and intelligence in the correspon- dence instituted between them. At the close of this review, we find ourselves shut up into a Pre-Estab- lished Harmony. But it is not the fanciful doctrine of Leibnitz. Accord- ing to him, no one power or monad can operate upon any other, but each fulfils its function independent of all others, and yet in harmony with all others. This seems to us quite inconsistent with what we see everywhere, the action of objects on each other. The Pre-Established Harmony which we advocate, pre-supposes the action of matter on matter, of matter on mind, and mind on matter, and the harmony is manifested in the benefi- cence of their mutual operation. This Pre-Established Harmony manifests itself in two forms. First, Agents mental and material have powers or properties which fit into each other, and enable them to co-operate in producing consistent and bountiful results. So far from supposing that they do not act on each other, we affirm, that they do act, but act in harmoh}^ Secondly, There has been an original collocation of agents, whereby concordant results are produced without any reciprocal action. The lily that grows in one garden, assumes the same forms and colours as tl>e lily which grows in another garden. The fish of the Old Red Sandstone epoch had the same general form as the fish which still swims in our seas. But these correspondences do not arise from any mystic or magnetic influ- ence of the one upon the other, but because causes have been instituted and arrangements made, which produce the one in unison with the other. The compari.son of Leibnitz here applies ; the two correspond as two time- pieces, not because of any mutual influence, but because each has been so constituted, that it moves in harmony with the other. We cannot comprehend the harmonics of t)io universe without admit- ting and callmg in both these principles. CHAPTER III. TYPICAL SYSTEMS OF NATURE AND REVELATION. SECT. I. THE OLD TESTAMENT TYPES. In looking at any one department of contemporaneous nature, we discover that all objects and events are con- formed to a plan. Organisms differing from each other in their constituent elements have the same relations of parts, and differing from each other in use, are cast in the same general mould. Again, looking at certain de- partments of successive nature, we find that objects in one epoch are an antici2)ation ox prediction of objects to ap- pear at a later epoch. The science of embryology shows that there are systematic stages of progression in the for- mation of the young of all animals. In the Psalm which celebrates the omniscience of God, this remarkable lan- guage is employed : — " I will praise Thee ; for I am FEARFULLY AND WONDERFULLY MADE : MARVELLOUS ARE Thy WORKS ; and that my soul knoweth right well. My substance was not hid from Thee, when I was made in secret, and curiously wrought in the lowest PARTS of the earth. ThINE EYES DID SEE MY SUBSTANCE, YET BEING UNPERFECT; AND IN ThY BOOK ALL MY MEMBERS WERE WRITTEN, WHICH IN CONTINUANCE WERE FASHIONED, WHEN AS YET THERE WAS NONE OF THEM." Thcse twO great truths are seen in beautiful combination in geology. THE OLD TESTAMENT TYPES. 505 which reveals a typical system, that is, all things formed after a type, in every age, and also a grand system of prophecy, in which the past ever points to the future, and the future appears as the accomplishment of the presentiments of the past. Lower animals appear as a prognostication of higher, and the higher come as . the fulfilment of the prediction set forth in the lower, and this not by any physical emanation of the one from the other, but according to the eternal plan of Him who hath therein showed the immutability of His counsel. There is an order in successive, even as there is an order in contemporaneous nature ; but as the one plant does not produce the other plant, which in the same type may be growing alongside of it, so neither docs a species of animal in one age produce the homologous species in a succeeding age. In this divinelj^-predetermined progres- sion man stands as the end or consummation of a process which had been going on since the dawn of creation. Views like these have been floating before the minds of deep thinkers and large-minded observers for the last two or three ages, and were expressed by some who did not discover their true meaning. We find Herder writ- ing, at the end of last century, " See how the different classes of creation run into each other ! How do the organizations ascend and struggle upward from all ])oints on all sides ! And then, again, what a close resemblance between them ! Precisely as if, on all our earth, the form-abounding mother had proposed to herself but one type, one proto-plasma, according to which, and for which, .she formed them all. Know thou what tliis form is. It is the identical one which man also wears. It is more evident internally than it is externally. Even in insects an analogon of the human anatomy has been discovered, though, compared with ours, enveloped and seemingly 506 THE OLD TESTAMENT TYPES. disproportionate. The different members, and conse- quently alsp tlie powers which work in them, are yet undeveloped, not organized to our fulness of life. It seems to me that throughout creation this finger-mark of nature is the Ariadne thread that conducts throuo-h the labyrinth of animal forms, ascending and descending."* A similar passage, very probably suggested by that quoted from Herder, (but without any acknowledgement to this effect,) is found in Coleridge's Aids to Eeflection.-j- " The metal at its height seems a mute prophecy of the coming vegetation, into a mimic resemblance of which it crystal- izes. The blossom and flower, the acme of vegetable life, divides into component organs with reciprocal func- tions, and by instinctive motions and approximations seems impatient of that figure by which it is differenced in kind from the flower-shaped Psyche that flutters with free wing above it. And wonderfully in the insect realm doth the irritability, the proper seat of instinct, while yet the nascent sensibility is subordinate thereto — most wonderfully, I say, doth the muscular life in the insect, and the musculo-arteria in the bird, imitate and typi- cally rehearse the adaptive understanding, yea, and the moral affections and charities of man. Let us carry our- selves back in sj)irit to the mysterious week, the teeming work-days of the Creator, as they rose in vision before the eye of the inspired historian of the operations of the heavens and of the earth, in the day that the Lord God made the earth and the heavens. And who that watched their ways with an understanding heart could, as the vision evolved still advanced towards him, contemplate the filial and loyal bee, the home building, wedded and divorceless swallow, and above all the manifoldly intel- ligent ant tribes, with their commonwealths and con- * Metempsychosis. t Aph. xsxvL THE OLD TESTAMENT TYPES. 507 federacies, their warriors and miners, the husband folk that fold in their tiny flocks on the honey's leaf, and the mgin sisters with the holy instincts of maternal love detached, and in selfless purity, and not say in himself, Behold the shadow of approaching humanity, the sun rising from behind in the kindling morn of creation \" Nor are these the visionary dreams of a poet or a mystic, clothing nature in forms devised by his own fantasy ; they are (after deducting one or two slight misa])prc- hensions of fact) the results reached by the profoundest inductive science of our times. Between this typical system in nature and our powers of intelligence, there is a beautiful corresjjondence. First, there is in the human mind an imagining faculty, which experiences a strange delight in reproducing what it has perceived under a kind of ideal or pattern form. We have seen, let us suppose, a particular plant, say the Victoria Regina, we cannot remember every insignificant particular connected with the number of its ribs or veins, but there is laid uj^ in our minds a general outline of its shape, colour, and structure, which enables us on any other plant of the sort falling under our notice, at once to recognise it as belonging to the same species. The mind seems thus to idealize to some extent its very re- collections. And then in the higher intellectual processes of a])straction and generalization, it abstracts the indif- ferent and retains the essential, and strives to grou[) the innumerable objects which it meets with under a few heads, by means of their common qualities. The rela- tions thus discovered, cause the classes and individuals to recur again and again to the mind according to the law of association, and even aid the mind in the perception of certain kinds of beauty. v These are the topics whicli have passed before us in 508 THE OLD TESTAMENT TYPES. the previous part of this Work. We are now to trace another correspondence — it is equally wonderful — -between the typical system of nature, and the typical system of revelation, and to show that this second is as admirably suited as the first to the native capacity and tendencies of the mind. It has long been known to divines, that the Word of God has a typical system. The types have not been always expounded in the exercise of a sound judgment, or in accordance with the principles which should govern all Scripture interpretation. Not unfrequently imagin- ation has been allowed unreined to career in this field at will, and in all treatises of divinity, the word type has been changed from its scriptural to a theological sense. In other cases, the fanciful interpretations which have collected around the types of Scripture have led men of severe critical taste to reject the whole system as visionary. Still it is obvious that types run through the whole Word of God, and cannot be excluded from it without mutilating the Old Testament, and even parts of the New Testament, so as to deprive them of some of their most marked features. But now where such curious harmonies and prefigurations have been detected in the organic world, we may be able to show that no one is entitled summarily to reject Scripture types as being contrary to reason, or the analogy of things, and even to trace an analogy between the types of the Works and of the Word of God. Not that the two systems are the same ; they are not identical, but homologous or analo- gous. If the principles which we have been unfolding are well founded, there should, with the uniformity, be also a diversity. The typical system of the animal king- dom is of a different order from the typical system of the vegetable kingdom ; and when we rise from matter to THE OLD TESTAMENT TYPES. 509 mind, from nature to revelation, we may expect tlie typical system to be of a higlier kind than that which pervades the organic world. There is the same method in all, and this suited to the intellectual tendencies of mankind, but it is varied to suit the end which each has to accomplish. In the theological use of the ]-)hrase, the word type is confined to tlic prefigurations of Christ set forth in the Old Testament. In books of divinity we read of certain ordinances as the type, and Christ as the antitype. But this is not the sense in whi.ch the term is used in Scrip- ture. Mr. Fairbairn, in his able work on Typology, says, that he understands the word in the theological sense, but adds, " as employed in Scripture it is used with greater latitude, as may be seen by consulting in the original the passages referred to," (Hob. viii. 5 ; 1 Cor. X. 6 ; Phil. iii. 17 ; 1 Thess. i. 7 ; 1 Peter v. 3 ; Rom. \\. 17.) But " the foolishness of God is wiser than men." We do not know what ri^lit divines have to construct a system of theological types, instead of a system of Scrip- ture types. We are sure that had they kept to the Scripture use of the term instead of devising a theolo- gical sense, they would have been saved from mucli ex- travagance, and have evolved much more truth. The words em])loyed in Scripture (m'tio/, (j/ioc^^^/y/z^n/) stand for pattern-figures, or examples ; and persons living in ages widely different from each other, and events having no natural connexion, are represented as being constituted after the same type or model. There are tyjjical occur- rences mentioned in Scripture, and full of instruction, wliich have no immediate connexion witli thi- ))ers<»n of Clirist, and are in no way prefigurative of llini. Thus the judgments of God fell on the children of Israel in the wilderness as types or "exam})leH" (1 Cor. x. 11) of a method oi' procedure which is for ever the same, and 510 THE OLD TESTAMENT TYPES. recorded "for our admonition/' in order to shew tliat it will be put in execution whenever men commit similar deeds. Types did not cease when Christ appeared ; there are types in the New Testament dispensation (Phil. iii. 17 ; 1 Thess. i. 7 ; Kom. vi. 17) as well as in the Old Testament dispensation. The tj'pical system of the kingdom of grace is meant fundamentally and primarily to shew that Grod proceeds according to one counsel and purpose from age to age. In this respect there is an exact correspondence between the typical systems of re- velation and nature. But as in nature there are fore- shadowings revealed by embryology and geology, so in revelation there is also a scheme, and this a very grand scheme, of prefiguration. In the natural kingdom all inferior organisms point onward and upward to man ; in the spiritual kingdom all life points onward and upward to Christ. Theologians, in discussing types, have con- fined their attention exclusively to these prcfigurations ; but in neglecting the other and wider view, they have not only missed much instruction, but have not been able to estimate precisely the meaning of the important truths to which their attention has been called. It strikes us that a typical system runs through the whole Divine economy revealed in the Word. First, Adam is the type of Man. He and his posterity are all of the same essential nature, possessing similar powers of intuition and understanding, of will and emotion, of conscience and free agency, and God acts towards them in the dispensations of grace as in the dispensations of nature, as being one. Then, from the time of the Fall, we have two different typical forms, the one after the seed of the serpent, the other after the seed of the woman. Henceforth there is a contest between the serpent and Him who is to destroy the power of the serpent, between THE OLD TESTAMENT TYPES. 511 the flesh and the Spirit, between the world and the Church. Two manner of people are now seen struggling in the womb of time — a Cain and an Abel, an Ishmael and an Isaac, an Esau and a Jacob, an Absalom and a Solomon, the elder born after the flesh, and the younger born after the Spirit. It is this unity of figure fully as mucli as the " tjqje" of sound doctrine which gives a con- sistency, in the minds of believers, to our religion in all ages ; which enables the Christian to profit, to this day, by the teaching of the Old Testament ; to sing, to this day, the song of Moses and the Psalms of David ; and to per- ceive and feel that there are the same contests now as then, the same contests in the heart, the same contests in the world, between the evil and the good principle, between the first, or nature-born, and the second, or grace-born. In short, there are now, as there have ever been, but two men on our earth typical or representa- tive ; the first man, which is Adam, the second, which is Christ. " And so it is written. The first man Adam was made a living soul ; the last Adam was made a quickening spirit. Howbeit that was not first which is spiritual, but that which is natural ; and afterward that wliich is spiritual. The'first man is of the earth earthy ; the second man is the Lord from heaven." There appear from age to age certain great leading powers of the first or earthy form, distinguislicd by their audacity and the oppression which they exercise over the Churcli, such as Cain and Lamech, Ham and Nimrod, Egypt and Babylon. " They liave consulteil together with one consent ; they are confederates against thee ; the tabernacles of Edom and the Ishmaelites, of Moab and the Hagarenes, Gebal and Animon and Anielek, with the inliabitants of Tyre : Assur also is jnlncd with ihciii, they liuve holpen the children oi" Lot." These are repre- 512 THE OLD TESTAMENT TYPES. sented in Christian times by Gog and Magog and Babylon, But we must confine our attention here to the examples of the better type, which appear and reappear throughout successive ages, and chiefly, in this section, to what is, after all, the most important, to the prefigurations of Christ. It had been determined, in eternity, that, " He whose delights were with the children of men," should come to our earth in the fulness of time. He is called "the Lamb slain from the foundation of the world ;" and as soon as man falls, there are symbols of Him : " Lo, I come, in the volume of the book it is written of me." The prefigurations of Christ may be divided into three classes : — typical ordinances, personages, and events. First, There is a number of ordinances, more or less of the same general mould, all imparting substantially the same instruction, all pointing to guilt contracted, to God offended, to a propitiation provided, and to acceptance secured through this propitiation ;— the four great car- dinal truths of revealed religion, as addressed to fallen man. There were sacrifices, in which the offerer, placing his hand on the head of the animal, and devoting it to destruction in his room and stead, expressed symbolically his belief in those great saving truths. There was the tabernacle, with the people worshipping outside, and the Shechinah, which had to be sprinkled with blood, in its innermost recesses, pointing to an offended God, but a God who was to be propitiated through the shedding of blood. There was the ark of the covenant, with the tables of the law inside, and the pot of manna, and the rod that budded, and, over all, the cherubim shadowing the mercy- ^eat — fit symbol of an arrangement by which the law is fulfilled, and provision made for a revival of life, and a supply of spiritual food by a God ready to meet Avith, THE OLD TESTAMENT TYPES. 513 and to commune witli lis on tlie mercy-seat. There is the scape-goat, with the sins of the people laid upon it, pointing, as clearly as the Baptist did, to " the Lamb of God, which taketh away the sins of the world." Secondly, There are typical persons, such as Abel and Enoch, Noah and Abraham, Moses and Aaron, Samuel and David, Elijah and Elisha, shadowing the prophetical, priestly, and kingly offices of Christ. From the fall doAvnwards there is a succession of such personages, with their individual differences, but all after a pre-determined model, exhibiting certain features of character in as marked a manner as the Jewish race show certain fea- tures of countenance. As the clouds reflect the rays of the sun before he appears above the horizon, so each of these, though dark in himself — alas ! at times, shewing his native darkness, reflects certain of the beams — most commonly coloured, of the Sun of Righteousness, and shows that he is about to shine ujoon our world. Thirdly, There are typical events, exhibiting the same truths in a still more impressive form. There is the flood, in which many perish, but a few, that is, eight souls, are saved by an ark symbolical of the Saviour. There is the destruction of Sodom, in which the inhabi- tants perish, while Lot and his family are rescued by hea- venly interposition. Most instructive of all, and, there- fore, occupying the most important place, thfu-e is the deliverance from Egypt. The state of the Hebrews as bondsmen, the deliverer prepared for his work by suffer- ing, the method of the deliverence in the midst of con- tests and judgments, the wonderfully instnictivc journey through the wilderness, with tlie provision made for the sustenance of the people, and the statutes delivered are as certainly anticipations of a higher redemption to fol- lf>w, as the fish and reptiles' digits are anticipations of 514 THE OLD TESTAMENT TYPES. the lingers of men. It is all true history, and yet it looks as if it were a j^arable written by some man of God for our instruction. We are trained in this training of the children of Israel ; and by means of the discipline through which they were put, our imagining faculty has acquired some of our clearest and livehest, some of our most profound and comforting representations of the method of redemption. But we cannot understand the meaning of these ordi- nances, personages, and events, unless we take along with us both of the two grand principles which we have been unfolding in this volume. We must not confine our attention to their general homology, we must take into account also their special adaptations. We must not look upon them merely as prefigurations, we must look upon them as also " a figure for the time then present." (Heb. ix. 9.) These typical ordinances, persons, and events, are all after the same general plan, and exhibit in shadow the truths which the sinner most requires to know, and especially the person and work of the expected One under interesting and instructive aspects. But they were all at the same time adapted with exquisite skill to their own particular age, and the circumstances of which they formed a part. The ordinances, for instance, were appropriate worship on the part of those who were re- quired to observe them, and, in some cases, they subserved important national and civil purposes. The persons who figure as types were all the while doing a work for their own day, and were, in most cases, we believe, unconscious that they bore a representative character — they were conscious only of looldng onward to the light, and they wist not that their face was shining with the reflection of that Ught. The events, too, did, in most cases, impart a special lesson of their own, and, in all cases, were most THE OLD TESTAMENT TYPES. 515 imj)oi-tant links in the chain of Providence. But just as the paddle of the whale serves a special purpose, but contains divisions not needfid to its special purpose; just as the chick's head contains typical bones not re- quired in order to its extrusion from the egg ; — so the Old Testament types, while each accomplishes an end of its own, have all, at the same time, certain common features of a prefigurative character. Like the different species in the vegetable and animal kingdoms, like the answerable organs in different species, they diverge on either side in order to suit a purpose ; but, meanwhile, they are all after one pattern. In human architecture, we are pleased to see that the portico and the passage leading from it have often a homology to the temple it- self. It is the same in the temple of God. The gate- way, and the pillars and avenues of approach, present the same general outline as the temple to which they form an entrance. The whole of this method of procedure is in beautiful adaptation to the native tendencies and acquired habits of the mind of man. The skilful teacher is accustomed to instruct his younger pupils by means of signs, and pictures, and comparisons ; it is thus that he conveys the ideas of remote objects and abstract truths. In the simpler stages of society, mankind can be taught general truths only by symbols and parables. Hence we find most heathen religions becoming mythic, or ex})laining their mysteries by allegories or national incidents. The great exemplar of the ancient philosophy, and tlie grand archetype of modern science, were alike distinguished by their possessing the power of corajjarison in a high de- irrec, iinil both have told us that man is best instructed ])y siinilitudeH. " It is difficult," says the (Juest in the Stutesuian of Plato, " fully to exhibit greater things 516 THE OLD TESTAMENT TYPES. without the use of patterns," (TntfaSeiyfinTa.) Lord Bacon, in more than one place, has declared, "As hiero- glyphics preceded letters, so parables are older than argu- ments. And, even now, if any one wishes to pour new light into any human intellect, and to do so expediently and pleasantly, he must proceed in the same way, and call in the assistance of jjarahles." It appears, then, that God was acting in accordance with the nature which He had given us, in His method of instructing the early Church. In Bible history there are no myths, but real events are made as lively as myths, and convey far more important instruction. And, even in Christian times, this representative system has been felt by all, but espe- cially by the simple and unlettered, to be a powerful means of imparting great vividness and picturesqueness to the inspired teaching. The truth is exhibited ; not, as in systems of divinity, as a bare abstraction ; not, as in the words of Scripture, by a phrase expressive enough, but still a mere counter, bearing no resemblance to that which it represents ; but by a picture which the mind, as it were, sees before it. With such lively images before us, we feel as if we were walking amid living realities. We find, in particular, that the types of the Bible have ever been especial favourites with the " common people," who experience a difficulty in seizing an abstraction, or in grasping a generalization, but feel none in compre- hending truths which are embodied in an incident, a person, or an ordinance. Take away the typical repre- sentations of the deeper doctrines of the Word of God, take away such figures as sacrifices, as the brazen ser- pent, as the scape-goat, the city of refuge, the sprinkhngs and ablutions under the law — abstract these from the apprehensions of the Christian who moves in the lower walks of life, and there would remain, we suspect, scarcely THE OLD TESTAMENT TYPES. 517 any idea — there would certainly be nothing remaining to enliven and engage the mind. It was in gracious accom- modation to the same peculiarities of our nature, that the greatest of all teachers, " He who knew what was in man," taught the people by parables. The right conclusion has been drawn by one in whose history difficulties have merely been " Schools and School- masters" to strengthen his native genius. " As the veil slowly rises," says Dr. Hugh Miller, " a new signiiicancy seems to attach to all creation. The Creator, in the first ages of his workings, appears to have been associated with what he wrought simply as the producer or author of all things ; but even in these ages, as scene rose after scene, and one dynasty of the inferior animals succeeded another, there was strange typical indications, which pre-Adamic students of prophecy, among the spiritual existences of the universe, might possibly have aspired to read — symbolical indications to the effect that the Creator was, in the future, to be more intimately con- nected with his material works than in these aojes, throuo-h a glorious creature made in his own image and likeness. And to this semblance and portraiture of the Deity — the first Adam — all the merely natural symbols seem to refer. But in the eternal decrees, it had been for ever determined that the union of the Creator with creation was not to be a mere union by proxy or semblance ; and no sooner had the first Adam appeared and fallen, than a new school of prophecy began, in wliicli type and symbol were mingled with what had now its first exist- ence oil»earlh ; and all pointed to the second Ailam, 'the Lord from Heaven.'* In Him creation and the Creator • Thin extract 1« from a notice by Dr. Miller of llio Artlclo In Uie North IJrItlsli Ucvlow previously n-fitrrod to. In tlie Raiiie artlolo lio shews wherein Okon hail erred. " Hcnco the remark of Oken, tliat 'tnon \n tlie sum total of all the uiilinals.' Heneo, too, but with tt ullll brooiler ai.preclatlou of the honiolo;,'le» which bear upon the lord of creation 518 TYPICAL NUMBERS. met in reality, and not in semblance ; on the very apex of the finished pyramid of being sits the adorable Mon- arch of all ; — as the son of Mary, of David, of the first Adam, the created of God — as Grod and the Son of God, the eternal Creator of the universe. And these — the two Adams — form the main theme of all prophecy, natural and revealed. And that type and symbol should refer not only to the second, but, as held by such men as Agassiz and Owen, to the first Adam also, exemplifies, we are disposed to hold, the unity of the style of Deity, and serves to shew that it was He who created the worlds, that dictated the Scriptures." SECT. II. TYPICAL NUMBEKS. There is no object on which a greater amount of extravagant statement has been made, both in ancient and modern times, than the significance of numbers. The Pythagoreans, and later Platonists, evidently sought for some inherent power in numbers to account for the numeral relations that appear in nature. In the pages of Philo-Judseus and Josephus, numbers have a theoso- phic signification. In more than one country, certain as their central type, his cssentiaHy profane and erroneous reniarli, that 'man is God manifest in flesh.' Let the reader, however, observe in what the error and profantlty consists. There is a loose sense in which man is God manifest in the flesh; — he is God's image manifested in the flesh ; and an image or likeness Is a manifestation, or making evident, of thai which it represents, whether it he an image or likeness of body or mind. Originally, at least in moral character, man was a manifestation of his Maker, and in intellect he is a manifestation of his Maker still. But the error and profanity of Oken consists in applying that to man, the image — man, the being in whom merely the homo- lognes or natural prophecies converge — which Is exclusively applied, in revelation, to a higher and more real manifestation of God in the flesh — that manifestation o£ very God himself which has formed the subject, not of natural, but of the revealed prophecies. The transcendentalist has gone, in his irreverent ignorance, a step too far; and yet his mean- ing seems real, though he himself mistook its nature, and employed improper language to convey it." — Witness, Aug. 1861. We may here be permitted to express a wish that the author will some time or other republish a selection from the articles in the Witness newspaper ; they would be acknowledged not to be inferior to the republications from any of the periodicals of our age. TYPICAL NUMBERS. 519 numbers have been supposed to have a magical power. Commentators have discovered a mystical meaning in the special numbers which appear and reappear so con- stantly in the Word of Grod. Others have not known what to make of Scripture numbers, while not a few have looked with suspicion upon the passages which contain them, or the Bible, because it is so full of them. The train of observation and reflection followed in this treatise, may help us to discover what is the true signifi- cancy of such numbers. In comprehending and recollecting the isolated and scattered phenomena of nature, and in the scientific con- struction of them, in order to these ends, man's intellect needs such recurring numbers, and when he does not find them in nature, he places them there. Man seeks them, too, in chronology, as an aid at once to the memory, which calls up events by the law of correlation, and the contemjilative intellect, which loves to collect objects into groups. So strong is this tendency, that when such re- lations are not found among events, mankind will create them from the stores of their own ingenuity., and will lengthen or shorten periods to suit them to the measure of their Procrustes' bed. Hence it is, that in the specu- lations of early philosophers, in history handed down by popular tradition, and in all mythic systems of religion, we have recurrent numbers, such as three and five, seven and ten. The existence of this mystical tendency in pre- mature scientific speculation, should not lead us, by an extreme reaction, to affirm tliat numbers have no signi- ficancy in nature ; it should merely guard us from adopting them too readily — that is, it should j)revent us from receiving them without inductive evidence, which is n• Flowers yellow and purple. Corolla white, with purple spots; the yellow anthers lie on the purple spots. Two petals white ; three are spotted with purple, and are yellow at the base. Leaves yellow-green and red-purple; corolla yellow and purple; ovary first yellow- green, then red-purple. Four petals yellow ; the fifth is yellow, with a purple spot, Corolla yellow ; tips of calyx purple. Corolla yellow; the odd lobe with purple veins. Four petals purple ; the odd petal lias a yellow spot. Flower yellow; the odd piece has purple streaks on the inside. Calyx yellow-green, and red-purple streaks; odd lobe of corolla yellow, with purple on the outside. 534 APPENDIX. Swainsonia purpurea, . Hieracium Pilosella, Aster acris, A. spectabilis, A. cordifolius, A. Novae An- glise, .... Rudbeckia fulgida, Corvisartia Helenium, . Gloxinia grandis, . Ajuga Chamsepitys, A. pyramidalis, Galeopsis Tetrahit, G. versicolor, Melittis grandiflora. Antirrhinum Orontium, Euphrasia officinalis, Linaria Cymbalaria, Schizanthus purpureus, Sarracenia purpurea, Rumex pulcher, . R. Acetosa, . R. aquaticus, Pinus sylvestris, and other Coniferse, . Ficus elastica, Drimys Winteri, . Taxodium sempervirens, Lycaste Skinneri, Corolla red-purple ; odd lobe with a vrhite eye. Flower yellow, outer surface of ray purple. >- Centre yellow, circumference purple. Centre purple, circumference yellow. Circumference and centre yellow ; inner scales of involucre red-purple, outer scales yellow- green; stems red-purple, foliage yellow- green. Odd lobe of corolla red-purple inside ; calyx yellow-green ; stalks red-purple. Flower yellow, with purple on odd lobe. Flower purple, yellow spot on odd lobe. Odd lobe yellow and purple. Odd lobe yellow and purple. Flower yellow, purple on the odd lobe. Flower purple, yellow on the odd lobe. Corolla purple streaked, yellow on the odd ^ lobe. Corolla purple, odd lobe with yellow spots and yellow hairs. Odd lobe of corolla yellow and purple. Pitcher red-purple and yellow-green. Anthers purple below, yellow above. Perianth red-purple and yellow-green. Stem red-purple ; dense masses of yellow- green flowers ; the latter have sometimes red-purple streaks. r Young cones purple and citrine. Buds red-purple, leaves yellow-green. Young shoot red-purple, young leaf yellow- green. Young shoot yellow-green; more advanced, red-purple ; when older, it is citrine. Monocotyledons. Sepals, outside yellow-green, inside red- purple ; two upper petals white, or yellow with purple spots; third petal yellow and purple spots. APPENDIX. 535 Brassia verrucosa, Oncidium Cavendishii, . Epidcndrum cochleatum, Lycaste aromatica, Caltleya Loddigesii, Oncidium Papilio, Cypripedlum venustum, Listera cordata, Iris pseudacorus, . I. Germanica, I. Tricolor, . Pandamis odoratissimus, Caladium pictum, . Strelitzia, several species, Curcuma cordata, and C ovata, Juncus compressus, Avena pratensis, . Papyrus antiquorum, Sepals and two upper petals yeUow-green and red-purple; third petal white, with green warts and yellowish eye; flower-stalks purple. ^ Third petal yellow and purple. Leaves red-purple and yellow-green. Petals yellow-green and red-purple; bract yellow-green, with red-purple line on the midrib, and one near each margin; ovary yellow-green, with red-purple lines corre- sponding to the adherent edges of the pieces of which it consists. Flowers red-purple and yellow-green. Flower yellow, with purple streaks ; stamens variegated with purple. Calyx yellow and purple ; corolla purple ; pollen yellow. Petals yellow ; sepals yellow and purj^le. Teeth and edge of leaf red-purple, centre yellow-green. Centre of leef red-purple, edge of leaf yellow- green. Leaf yellow-green, leaf-stalk red-purple; se- pals orange ; petals blue. ) Tip of bracts red-purple, base of bracts yel- 1 low-green ; flower yellow. Flower russet and green. Glumes citrine, with purple streaks and purple awn ; anthers yellow and purple. Sheaths red-purple ; stalks yellow-green. 1 INDEX, AcUnia, 271-275. Adaptation, principle of, 1, 80^-40, 421, 427-433, 514. .^thetic feelings, 137, 189, 145, 150, 151, 153, 431-492. Ampbipoda, 242. Analogues, 25, 292, 293, 308. Analysis, 452-454. Angles of leaf-veins and branches, 112- 116. A priori speculation, 468-470. Archetype skeleton, ISO. Armature of plants, 134. -Vristotle, 11, 465, 474. Articulata, 233, 266, 3.36-388. Association of ideas, 473-430. Back, vertebrae of, 195. Bacon, 13, 421, 466. Barnacles, 245, 246. Bat's wing, 210. liats, teeth of, 216. Beauty, 481-488. Birds, vertcbraj of, 198, 199; diverging appendages of, 207, 208 ; cutaneous mus- cles of, 295. Blood-corpuscles, 79. Bone, structure ol^ 77; typical form of, 185, .307. BracU, 91, 135. Branches. 112-119. Branchlupoda, 242. Buds, m. Butterfly, month of, 254-257. Calyx, 92, 186. Camel, 66. Cumpatiularla, 27.3. Carnlvora, teeth of, 218. Oirtllagc, 76. Caterpillar, 249. Cause aud effect, 467-470. Cell, 70-71. Centrum of vertebra, 178. Cephalopoda, 227. Cercbflluin, 287. Chance, 40-54. Chemical groups, 363. Cicero, 8, 9. Classification, 422-426, 451, 460-466. Coal epoch, flora of, 34S. Collocation, principle of, 34. Colours, 20-21, 53-58, 481. Colours of plants (and birds), 146-174. Comets, 391, 392. Complementary colours, 154-156. Cones an angles of, 112-116; structure of, 131, 132. Leech, 62. Leibnitz, 494, 495, 501-503. Ligaments, 75. Light, 406-408. Limbs, nature of, 189-192, 208-212. Loins, vertebras of, 195. Ludicrous, sense of, 144 note, 489. Magnetism, 19, 412, 413. Malebranche, 493. Man, preparations for, 346-353 ; distribu- tion of, 384. Mandibles of insects, 61, 252. MaxillK of insects, 258. Mechanical power, 32, 349, 350, 410, 411, 416, 417. Medusv, 277. Mollusca, archetype, 223-226; modifica- tions of, 227-232 ; fossil, 33S. Monsters, 429 note. Mountains, 871, 372. Muscle, 76, 294^298. Nails, 80. Neck vertebras, 194. Nervous tissue, 78 ; nervous system, 280- 288. Neural spine, 178. Neurapophysis, 178. Number as a principle of order, 11, 15-18, . 98, 188, 191, 192, 208, 215, 246, 270, 271, 814, 318, 518-525. Number, faculty which discovers rela- tions of, 458, 459. Ocean, 373; currents of, 379. Oken, 27, 181, 182, 434, 517 note.. Ophidia, skeleton of, 196-203; teeth of, 221. Order, principle of, 1, 420-427, 429-^39. 464, 467, 514. Ostrich, foot of, 209. Oviposltor.s, 264. Ox. foot of, 211. Phyllodia, 85. Physical geography, 370-382. Picturesque, 489, 490. Pines, morphology of, 119-129. Pistil, 94. Pitchers, 85. Planets, 389-891. Plant, typical, 103. Plato, 7, 11, 426, 465. Pleurapophysis, 178. Podura, 263. Pollen, 73. INDEX. 539 Pre-ostabllshed harmony, 431, 441, 442, 40-2-467, 470-473, 494, 495, 501-503. Trcfigurations of Christ, 512-514. rro£;re3.«lon, theories of, 817-'?26. Progressive plan in goolosy, 817-3'27. rrogressiro plan of Providence, 525-527. Property, faculty which discovers rela- tions of, 459, 4G0. Prophetic plan in geology, 827-33.5. Pteropoda, 8.j9. Pythagorean systeni, 10, 465, 518. Quincunx, 126. lladiafa, 267-279; fo.ssil, 814, 8-34-886. Rain, 377, 378. Uelations observed by mind, 450-452. Respiratory system, 291-294. Rodellt^ teeth of, 217. Sacral vertcbr r, 195. Schellin?. 471, 497-499. Seed, .structure of, 82; nature of, 95, 140. Sorpcnts, 60, 196-208. Shells of mollu.sca, 2S, 65, 66. 315. Skeleton, vertebrate, 175-212. Sloth, 67, 68, 197. Spina! cord, 2SS. Spines 80. SpinnoreL", 260. 837. Spinoza, 49.3, 494. Spinal arranKcment of appcndaffos of plant, 88-90, 96. 97; of conifcrae, 121- 128; offos.MIs,311. St. Ililairo, Geoffroy, 27, 431, 434. Stamens, 93, 137. Stars, 892-400. Stem, structure of, 84; typical form of, 187, 807. Stipules, 85, 183. Sublime, 490-192. Sun's rays, 151, 411, 413, 411. Supports of plants, 134. Tail of fish, .56,320. Tail vertebrn'. 200, 201. Teeth, 213-222; fos.sil, 842,843. Teleology. 30, 51, 423-438, 514, Tendons, 75. Time, as a principle of Order, 18-20. Time, faculty whicli discovers relations of. 456-4.58. Tortoise, 2iH. Types, 1, 23, 431, 456. Types, organic, ,364-366. Typical appendage of plant, 88. Typical bone, 185, 807. Typical cell, 69, 70. Typical Ii;nb, 192. Typical nuinber.s, 518-525. Typical plant, 103. Typical skeleton. 180. Typical sy.steni of Now Testament, 627- 532. Typical system of Old Testament, 508- 518. Typical tooth, 214, 215, Typical vertebra, 178. Universal.*, 406. Vascular system, 288-291. Vertebra, typical, 173. Vessels, 72. Whole and Parl.-<, faculty wliich discov- ers relations of, 4.52^54. Winds, trade, 374, 875. Wood, 72. # L 005 491 224 1 ,,.^JS°UTHFRN REGIONAL LIBRARY FACILITY AA 000 183 699