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Cornell University 
 Library 
 
 The original of tliis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924024756763 
 
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 ,,&ell doctrine: 
 
 3 1924 024 756 763 ... 
 
THE CELL DOCTRINE. 
 
BY THE SAME AUTHOR. 
 
 A GUIDE TO THE PRACTICAL EXAMINATION OF URINE. 
 For the use of Physicians and Students. Illustrated. Second 
 edition, revised and improved. Just ready. Price, ^1.25. 
 
 AN INTRODUCTION TO THE STUDY OF PRACTICAL HIS- 
 TOLOGY. For Beginners in Microscopy. Price, )J 1. 00; inter- 
 leaved, Si-So- 
 
 IN PREPARATION. 
 
 A TREATISE ON DISEASES OF THE KIDNEYS, with especial 
 reference to Pathology and Therapeutics. 
 
Fig. 1. Mg. S. ' Fig. 3. 
 
 Youngest layer. 
 
 Middle lay. 
 
 Proiluction of formed material from germinal matter In Epitlieliai cells, ir ui sectioa tlirougli layer uf Epitbelium 
 coveriug papillso oftlie tongue. X700. 
 
 Fig 7. ' ' ""j 
 
 Fig. 10. 
 
 ^//^>f^ 
 
 FORMATIOW OP PUS. 
 
 To illustrate the change in germinal matter of an Enithelial cell, resulting from increased nutrition, sbowing the 
 
 manaer In whioti the (fei'iuliial inacCBi- qi a normal cell, If supplied frcelv with pabulum, may give rise to pus. 
 
 
 a, SarCOl&miua, h, Cmitraetile matter. 
 MUSCLE. 
 
 Young. Fully fonr"1. Young. Fully formtsj. 
 
 TENDON. CAllTILAGE, 
 
 ELASTIC TISSUE. 
 The arrow showi the directiuii i>i which germiual 
 niaiter io ^^pt)osed to be movmg. 
 
 i 
 
 Dsvalopment of Toune, dark -bordered iierve flbres, at an early 
 ^itii-iod, ahowmg (^ermiiULl matter oud fbrmed material of 
 eiGmentaiT parte, x 1800, 
 
 fig. 17. 
 
 >Ma?BA. 
 
 Pure Knrmiiial matter. X5000. 
 
 New centre or nudeoluH 
 
 (xermiuulmaLter(nucleus)._ 
 
 Olftr^t T art of formed 
 111 Li -lal. 
 
 ^'unijeat pnrt of 
 :^_ li "II ed maiepial. 
 
 Course of pabulum. jg^^^^^T^-^ 
 
 PLATE ILLUSTRATING DR. BEALE'S VIEWS. 
 
THE CELL DOCTRINE: 
 
 ITS HISTORY AND PRESENT STATE. 
 
 FOR THE USE OF 
 
 STUDENTS IN MEDICINE AND DENTISTRY. 
 
 ALSO, 
 
 A COPIOUS BIBLIOGRAPHY OF THE^ SUBJECT. 
 
 By JAMES TYSON, M.D., 
 
 PROFESSOR OF GENERAL PATHOLOGY AHD MORBID ANATOMY IN THE UNIVER- 
 SITY OF PENNSYLVANIA ; ONE OF THE VICE-PRESIDENTS OF THE 
 PATHOLOGICAL SOCIETY OF PHILADELPHIA ; 
 ONE OF THE VISITING PHYSICIANS TO THE PHILADELPHIA HOSPITAL ; FELLOW 
 OE THE COLLEGE OP PHYSICIANS, PHILADELPHIA; 
 ETC., ETC., ETC. 
 
 SECOND EDITION, 
 
 REVISED, CORRECTED, AND ENLARGED. 
 
 ILLUSTRATED. 
 
 PHILADELPHIA: 
 LINDSAY & BLAKISTON. 
 
 1878. 
 
CORNELL^ 
 UNIVERSITY 
 
 LjBRAR\V 
 
 Entered according to Act of Congress, in the year 1878, 
 
 Br LINDSAY & BLAEISTON, 
 
 In the Ofi&ce of the Librarian of Congress, at Washington, D. C. 
 
 CAXTON PRESS OP 
 SHERMAN & CO., PHILADELPHIA. 
 
 JX 
 
THE MEDICAL CLASS 
 
 OF 
 
 THE UNIVERSITY OF PENNSYLVANIA, 
 
 aci)i6 Cittle ibolume 
 
 IS RESPECTP-ULLY INSCRIBED, 
 
 BY 
 
 THE AUTHOR. 
 
PEEFACE 
 
 TO THE SECOND EDITION. 
 
 The highly favorable and quite unexpected reception 
 accorded the first edition of this book has stimulated my 
 interest in the subject, and in preparing a second, I have 
 sought to improve it as much as possible. In doing so, 
 many of the original sources of my information have 
 been re-examined, and from them some additions made 
 and inaccuracies corrected. The section on the Present 
 State of the Cell Dootritie, incorporating my own views, 
 has been entirely rewritten, as was necessitated by the 
 very important and numerous contributions to the subject 
 since the first edition appeared. 
 
 The bibliography has been increased by the addition 
 of over three hundred and fifty new references, mostly 
 to papers contributed directly on the subject since the 
 first edition was issued. To make room for these, many 
 of the references included in the bibliography of the 
 first edition have been omitted where there did not seem 
 to be a sufficiently close bearing on the subject. 
 
Vlll PRKFACE TO THE SECOND EDITION. 
 
 The suggestion of one of the reviewers of the first edi- 
 tion, that the bibliography should be chronologically in- 
 stead of alphabetically arranged was carefully considered, 
 and at one time I had concluded to adopt it, but when 
 I attempted to do so, I found that the inconvenience 
 resulting from the wide separation of several papers by 
 a single author, more than oflfeet the advantages of a 
 chronological arrangement. I therefore adhered to the 
 original plan. 
 
 For valuable assistance in collecting references and 
 examination of papers I am greatly indebted to my as- 
 sistant. Dr. H. F. Formad. 
 
 1506 SPBrcE Street, 
 October 1st, 1878. 
 
PEEFACE 
 
 TO THE FIEST EDITION. 
 
 The author has become convinced, by several years' 
 intimate intercourse with students of medicine, that their 
 acquaintance with the subjects he has endeavored to in- 
 clude in this little volume would be facilitated, if the 
 views, which are now taught and scattered throughout 
 the often expensive works of their authors, were collected 
 in a convenient form for study and reference. Taking 
 it for granted that a knowledge of this subject is of fun- 
 . damental importance in its bearing upon the study of 
 physiology and pathology, and stimulated by the frequent 
 inquiries of students for an appropriate source of infor- 
 mation, he has prepared what he now submits to them. 
 
 He has sought to obtain a continuous history of the 
 evolution of the " cell doctrine " up to its present state, 
 without embarrassing his pages with a large number of 
 isolated facts. He has attempted, however, to secure a 
 completeness, and to make the work useful to physicians 
 
X PREFACE TO THE FIRST EDITION. 
 
 and others engaged in research, by careful references, and 
 the addition of a bibliography, which he has sought to 
 make accurate and extended. Some authors may have 
 been overlooked; such the writer cordially invites to 
 send him references to their own papers, or to those of 
 others they believe to have a bearing upon the subject. 
 
ILLUSTRATIONS. 
 
 Plate. — Illusteatistg Db. Bbale's Views. 
 
 Figs. 1 to 7. Production of formed material from germinal matter in 
 epithelial cells, from section through layer of epithelium 
 covering papillae of tongue. 
 
 Figs. 7 to 11. Formation of Pus. 
 
 Fig. 11. 
 
 a 
 
 " Tendon. 
 
 Fig. 12. 
 
 a 
 
 " Cartilage. 
 
 Fig. 13. 
 
 Cl 
 
 " Muscle. 
 
 Fig. 14. 
 
 n 
 
 " Elastic Tissue 
 
 Fig. 15. 
 
 it 
 
 " Nerve. 
 
 Fig. 16. 
 
 Amoeba. 
 
 
 Pig. 17. 
 
 Illustrating 
 
 Nutrition of Cell. 
 
 Intercalated. 
 
 Fig. 1. Illustrating Globular Theory. After Virchow. 
 
 Fig. 2. Cellular Tissue from the Embryo Sac of Chamsedorea Schie- 
 deana in the act of formation. After Schleiden. 
 
 Fig. 3. From the Point of a Branchial Cartilage of Eana Esculenta. 
 After Schwann. ■ 
 
 Figs. 4 to 12. Formation of Nuclei and Cells from Molecules, accord- 
 ing to Bennett. 
 
XU ILLUSTRATIONS. 
 
 Fig. 12. Diagram of the Investment Theory. From Virchow. 
 
 Fig. 13. Formation of Pus from subcutaneous connective tissue. 
 From Virchow. 
 
 Fig. 14. Formation of Pus from interstitial connective tissue of mus- 
 cle. From Virchow. 
 
 Fig. 15. Development of Cancer from connective tissue. From Vir- 
 chow. 
 
 Fig. f6. Connective Tissue Corpuscles anastomosing one with the 
 other. From Virchow. 
 
 Fig. 17. Formation of Elastic Tissue, according to Virchow. 
 
 Fig. 18. Formation of Connective Tissue, according to Schwann and 
 Henle. From Virchow. 
 
 Fig. 19. Formation of Connective Tissue, according to Virchow. 
 From Virchow. 
 
1^ 
 
 THE CELL DOCTRINE. 
 
 The idea that animals and plants, however com- 
 plex their organization, are really composed of a 
 limited variety of elementary parts, constantly re- 
 curring, was appreciated by Aristotle, who was born 
 384 years before Christ, while it appears to have 
 been little more clearly conceived by the acknowl- 
 edged father of medical science, Galen, who lived 
 400 years later. Aristotle distinguished as " partes ^ 
 similares," those structures, such as bone, cartilage, 
 fat, flesh, blood, lymph, nerve, ligament, tendon, 
 membrane, vessels, nails, hairs, and skin, which 
 were not confined to one part of the body, but 
 distributed throughout it generally. He applied 
 the term "partes dissimilares " to the regions of 
 the head, neck, trunk, and extremities. Fallopius 
 of Modena, 1523-1562, to whom we are indebted for 
 our knowledge of the conceptions of Galen in regard 
 to these " partes similares " or " simplices," has fur- 
 ther developed the subject of general anatomy in his 
 " Lectiones de Partibus Similaribus Humani Corpo- 
 ris." These, however, plainly do not correspond 
 with the " elementary parts " or " cells " of the pres- 
 ent day. As Prof. Huxley says in his valuable essay 
 
 2 
 
14 THE CELL DOCTRINE. 
 
 on "The Cell Theory," they were ultimate to Fallo- 
 pius, because he could go no further, " though it is, 
 of course, a very cliflferent matter whether we are 
 stopped by the imperfection of our instruments of 
 analysis, as these older observers were, or by having 
 really arrived at parts no longer analyzable."* These 
 " partes similares " really correspond to the " tissues " 
 of the present day, which are collections of elementary 
 parts. The conceptions of these older writers with 
 regard to the " vital endowment " or " independent 
 vitality " of their similar parts or tissues, were sin- 
 gularly correct, and correspond almost identically 
 with those held by the majority of physiologists of 
 the present day. 
 
 Further than this, however, the anatomists of the 
 period of Fallopius could not go — not because, as we 
 now well know, they had arrived at parts no longer 
 analyzable, but because of their imperfect means of 
 analysis. 
 
 It is probable that the magnifying properties of 
 lenses were known to the Egyptians, as well as the 
 Greeks and Romans, over 2000 years ago ; since 
 a table of refractive powers is introduced into 
 his "Optics" by Ptolemy, since Aristophanes, the 
 Athenian poet (B.C. 500), speaks of "burning 
 spheres" of glass as sold in the grocers' shops of 
 Athens, and since both Pliny and Seneca refer to 
 lenses and their magnifying properties ; while lenses 
 themselves have been found in the ruins of Nineveh, 
 
 * The Cell Theory— a Keview, by T. H. Huxley ; Br. and For- 
 eign Med. Chir. Kev. for October 1853, No. xxiv. 
 
THE CELL DOCTRINE. 15 
 
 Herciilaneum, and Pompeii. But it is quite certain, 
 also, that they did not become available as com- 
 pound microscopes until about 1590, when the Jan- 
 sens, father and son, of Holland, are said to have in- 
 vented the compound microscope. Fontana, in 1646, 
 writes that he had invented the microscope in 1618. 
 Galileo, as early as 1612, is said to have sent a micro- 
 scope to.King Sigismund of Poland, though whether 
 it was his own invention, or made after the pattern 
 of another, is not easily determined. In 1685, 
 Stelluti published a description of the parts of a bee 
 he had examined with the microscope, and although' 
 George Hufnagle is said to have published in Frank- 
 fort, in 1592, a work upon insects, illustrated by fifty 
 copper plates, it is highly probable that these, as well 
 as very many most important observations made after 
 the invention of the compound microscope, were 
 made with the simple instrument.* 
 
 It is impossible to estimate the assistance the 
 microscope has been to us in opening up the minute 
 structure of animals and vegetables, and in thus af- 
 fordins; a reliable basis on which to build a doctrine 
 of organization. Prof, lluxley further says, " The 
 influence of this mighty instrument of research upon 
 biology, can only be compared to that of the galvanic 
 battery, in the hands of Davy, upon chemistry. It has 
 enabled •proximate analysis to be ultimate."\ But it 
 is more than this. Since, as he correctly states, it 
 
 * Piir Hn interesting and exhaustive history of the invention of 
 the compound mici-oseopp, see Das Mikroskop, Theorie, Gebrauch, 
 Geseliic'hte und gegenwartiger Zustand dessclben. Von P. Hurting. 
 In drei Bandon. Braunschweig, 1866. Dritter Band, ss. 1-35. 
 
 f Huxley, loc. citat., p. 290. 
 
16 THE CELL DOCTEINE, 
 
 has enabled proximate physical analysis to become 
 ultimate, it corresponds, not to the galvanic battery 
 alone, but to all the appliances made use of in ulti- 
 mate chemical analysis. 
 
 The time prior to the invention of the compound 
 microscope may be considered as the first period in 
 histology ; that between this date and that of the ob- 
 servations of Schleiden and Schwann (1838), inclu- 
 sive, the second period ; while the time subsequent to 
 these observations becomes appropriately the third 
 period. Notwithstanding the imperfect state of in- 
 struments during quite two hundred years after the 
 invention of the compound microscope, a flood of 
 facts was added to oar knowledge of the minute 
 structure of living things, 
 
 Borellus, of Pisa, seems first to have used the mi- 
 croscope in the examination of the higher animal 
 structures, about the year 1656, but his observations 
 were grossly misinterpreted in his attempt to adapt 
 them to the prevailing idea of the day, that diseases 
 were caused by animalculse in the blood and tissues. 
 As a result, he describes pus-corpuscles as animalcules, 
 and even says he has seen them delivering their eggs. 
 
 According to Boerhaave, Swammerdam had recog- 
 nized the blood-corpuscle in the frog in 1658. 
 
 Malpighi,* between 1661 and 1665, had seen the 
 blood -corpuscle in the hedge-hog, had witnessed the 
 circulation of the blood, and had published observa- 
 tions upon the minute structure of the lungs, which 
 he had even compared to a racemose gland,t of the 
 
 * Malpighi, Opera Omnia. London, 1686. 
 
 t Fort, Anatomie et Physiologie du Poumon, considere comme 
 
THE CELL DOCTRINE. 17 
 
 kidneys, spleen, liver, and membranes of the brain, 
 and with some of these structures his name has 
 become inseparably associated. In 1667, Robert "i 
 Ilooke* pointed out the cellular structure of plants, 
 and Malpighif further elaborated the same subject 
 with considerable accuracy in his " Anatome Planta- 
 rnm," in 167i>. He showed that the walls of the 
 " cells " or " vesicles," were separable, that they could 
 be isolated, and gave to each the name " utrioulus" 
 believing also the " cell," or " utriculus," tb be an 
 independent entity. The latter observer;]: also recog- 
 nized the blood corpuscle. Leeuwenhoek, in 1673,§ 
 described these corpuscles with considerable accuracy, 
 not only in man, but also in the lower animals. He 
 also demonstrated the capillaries, examined most of 
 the tissues, and made the discovery of the sperma- 
 tozoids, which he conceived to be spermatozoa or 
 sperm animals, and of diiJerent sexes. 
 
 Theory of Sailer, 1757. — N"o attempt, however, 
 seems to have been intelligently made at building up 
 the tissues by an ultimate physical element, to cor- 
 respond with the " atom " of the inorganic chemist, 
 prior to that of Haller. He resolved the solid parts 
 of animals and vegetables into the '■'■fibre" {fibra), 
 
 un organe de Secretion. Piivis, 1867, Preface; or a notice of Dr. 
 Fort's book, by the writer, in American Journal of Medical 
 Sciences, October, 1869. 
 
 * Hooke, Rob., Micrographia. London, 1C67. ^ 
 
 f Slalpighi, Anatome Plantarura. London, 1670. 
 
 X Malpighi, Opera Posthuma. London, 1697. 
 
 g Leeuwenhoelj, Opera Omnia seu Arcana Naturas detecta. 
 Tom. ii, p 421. Leyden, 1687. Vel Opera Omnia, etc., Lugd. 
 Batav., 1722. 
 
 2* 
 
18 THE CELL DOCTRINE. 
 
 and an " organized concrete." To the former he as- 
 signs the most important position, asserting that it 
 is to the physiologist what the line is to the geome- 
 trician ; that a "fibre," in general, may be con- 
 sidered as resembling a line made up of points, 
 having a moderate breadth, or rather as a slender 
 cylinder.* 
 
 The second elementary substance of the human 
 ' body according to Haller, the " organized concrete," 
 must not be lost sight of, as appears to have been 
 the case with many eminent authorities who have 
 attempted to give his views. This, he says, is a 
 mere glue, evasated and concreted, not within the 
 fibres, but in the spaces betwixt them, in illustration 
 of which it is stated, that cartilages seem, to be 
 scarcely anything else besides this glue concreted. 
 But these views of Haller were clearly not based upon 
 microscopic observation, though the microscope had 
 been for some time in use. For Haller himself tells 
 us that the fibre is invisible, and to be distinguished 
 only by the "mind's eye," — invisihilis est ea Jibra, 
 sold mentis acie distinguimus.\ No allusion, to the 
 cell beyond the imperfect description of the blood- 
 
 * Haller, Elementa Physiologise, vol. i, lib. i, sec. i. Lausan., 
 Helvet.,1757. 
 
 ■j- A singular discrepancy exists between these words of Haller 
 and those found in both the Latin and English editions of the 
 " elegant compend " of Haller's works printed in Edinburgh, the 
 former in 1766, and the latter (an edition in the possession of the 
 writer), in 1779, under the inspection of William CuUen, M.D. 
 In the latter, we have the following : " The solid parts of animals 
 and vegetables have this fabric in common, that their elements, or 
 
THE CELL DOCTRINE. 19 
 
 corpuscles and spermatozoids appears to have been 
 made by Haller. 
 
 Theory of Wolff, 1759-74.~Better founded, in 
 being based upon observation, was the theory of 
 Wolff, and it contained many of the elements of 
 truth. For an available exposition of these views, 
 physiologists are much indebted to Prof Huxley, 
 who in the able review already cited, has pre- 
 sented them as agreeing partially, also, with his 
 own. The doctrine of Wolff, as given by Prof. 
 Huxley, is as follows : " Every organ is composed, at 
 first, of a mass of clear viscous, nutritive fluid, which 
 . possesses no organization of any kind, but is at most 
 composed of globules. In this semifluid mass, cavi- 
 ties (Blaschen, Zellen) are now developed ; these, if 
 they remain rounded or polygonal, become the sub- 
 sequent cells, if they elongate, the vessels ; and the 
 process is identically the same, whether it is ex- 
 amined in the vegetating point of a plant, or in the 
 young budding organs of an animal. Both cells and 
 vessels may subsequently be thickened by deposits 
 from the ' solidescible ' nutritive fluid. In the plant, 
 the cells at first communicate, but subsequently be- 
 come separated from one another ; in the animal, 
 they always remain in communication. In each case,, 
 they are mere cavities and not independent entities ; or- 
 ganization is not effected by them, hut they are the visible 
 results of the action of the organizing power inherent in 
 
 the smallest parts we can see hy the finest microscope, diVe either 
 fibres or an organized concrete.'" 
 
 ' First Lines of Physiology. By the celebrated Baron Albertus Haller, M.D. 
 Translated from the correct Latin edition, and printed under the. inspection of 
 William Cullen, M.D. Edinburgh, 1779. 
 
20 THE CELL DOCTRINE. 
 
 the living mass, or what Wolft' calls the vis essentialis. 
 For him, however, this vis essentialis is no Archceus, 
 hut simply a convenient name for two facts which 
 he takes a great deal of trouble to demonstrate ; the 
 first, the existence in living tissues (before any pas- 
 sages are developed in them), of currents of the nu- 
 tritious fluid determined to particular parts by some 
 power which is independent of all external influence ; 
 and the second, the peculiar changes of form and 
 composition, which take place in the same manner."* 
 'Two points are here particularly to be observed as 
 cardinal, — first, the non-independence of cells, either 
 anatomically or physiologically ; that they are effects, 
 passive 'results, and not muses of a vitalizing or or- 
 ganizing force ; second, that organization takes place 
 from the " differentiation " of the homogeneous 
 living mass in these parts, through the agency of the 
 vis .essentialis or inherent vital force. The radical 
 difterence between these principles of development 
 and those generally held at the present day, will be 
 better appreciated when these latter have been 
 worked out. An acknowledged error may, however, 
 be pointed out, — the probable result of the inferiority 
 of the instruments of that day — that of supposing 
 the cells of plants and animals in all instances to 
 communicate when in their youngest state, and in 
 the latter to continue thus in communication through- 
 ,out life. It will be observed, also, that this theory 
 involved the spontaneous origin of the cell, that is, 
 independent of any previously existing cell. 
 
 * Huxley, loo. citat., p. 293-4. Wolff, 0. P., Theoria Genera- 
 tionis, 1769. Ed. Nova, Halae, 1774. 
 
THE CELL DOCTRINE. 21 
 
 The theory of Wolff, however, full as it was of origi- 
 nal conception, and based on actual observation, seemed 
 to claim little attention, and would have been still 
 less known but for the labors of Prof. Huxley. The 
 " fibre " theory of Haller was still further expanded, 
 and that fibres were the groundwork of nearly all 
 the tissues, continued the prevailing view, until the 
 latter part of the eighteenth century, and there are 
 few of the older Physiologies even of a later date, 
 which do not contain an account of it. IsTaturally, 
 it maintained itself longest in the case of the fibrous 
 tissues, since the appearances of these tissues, when 
 examined by the highest powers, are those of struc- 
 tures apparently composed of fibres. 
 
 Oken, 1808 .-^The first clear expression with regard 
 to the cellular or vesicular composition of animal or- 
 ganisms as well as vegetable, comes from the physical 
 school in the language of Oken, who, as early as 
 1805, in his work on " Generation," refers to elemen-~' 
 tary parts as " vesicles;" and who says in his " Pro- 
 gramm fiber das Universum " in 1808, " The first 
 transition of the inorganic to the organic is the con- 
 version into a vesicle (Blaschen), which I, in my 
 theory of generation, have called infusorium. Ani- 
 mals and plants are throughout nothing else than mani- 
 foldly divided or repeating vesicles, as I shall prove 
 anatomically at the proper time." This most ex- 
 plicit statement seems also to have been overlooked. 
 The Globular Theory, 1779-1842.-.-The reaction 
 which took place at the date referred to against the 
 ■ " fibre " theory, culminated in the " globular '' theory,' 
 due less to speculation than erroneous methods of ob- 
 
22 THE CELL DOCTRINE. 
 
 * 
 
 servation and imperfect instruments. Leeuwenhoek* 
 (1687) early announced the "globular" structure of 
 the primitive tissues of the body, but the " globule" 
 apparently attracted little notice until this period of 
 reaction against the " fibre," when it claimed the 
 attention of Proehaskaf (1779), Fontana:): (1778), the 
 brothers Wenzelg (1812), Treviranus|| (1816),Eauerl 
 (1818 and 1823), Heusinger** (1822), MM. Prevost 
 and Dutnas,tt Milne- Ed wards ft (1823), Hodg- 
 kin§§ (1829), Baumgartner|l|| (1830-42), Frederick 
 
 * Lceuwenhoek, op. citat. 
 
 f Proehaska, De Structura Nervorum. Vind., 1779. Opera 
 min., Piirs i. 
 
 J Fontana, Sur les Poisons, 1787, ii, 18; Abhandlung tiber das 
 Viperngift, das Amerikanische Gift, u. s. w. Aus dem Italian. 
 Berlin, 1787. 
 
 § Wenzel, Joseph and Charles. De structura cerebri. Tubing., 
 1812. * 
 
 II Treviranus, Vermischte Schriften, Anatom. und Physiolog. 
 Inhalts Bd. i. Gottingen, 1816. 
 
 T[ Bauer, Philosoph. Transac. for 1818, and SirE. Home's Lec- 
 tures oil Comparative Anatomy, vol. iii, Lect. iii. London, 1823. 
 
 ** Hi'usinger, System der Histolngie. Thl. i Eisenauh, 1822-4 
 
 ft MM. Prevost and Dumas, Bibliothdquo Universulle des Sci- 
 ences et Arts, T. xvii. 
 
 Xt Milne-Edwards, M^moire sur la Structure Elementairo des 
 Principaiix Tissues Organiques des Animaux. Paris, 1823. Also, 
 Eecherches Microscopiques sur la Structure Intime des Tissues Or- 
 ganiques des Animaux, in Ann. des Sci. Nat. December, 1826. 
 
 ?§ Hodgkin, in Grainger's Elemontsof General Anatomy. Lon- 
 don, 1829. Also Hodgkin and Fisher's translation of M. Edwards 
 " Sur les Agens Physiques." London, 1832. Hodgkin's Lectures 
 on the Morbid Anatomy of the Serous and Mucous Membranes. 
 London, 1836, p. 26. Am. Ed., Philadelphia, 1838, vol. i, pp. 
 ■17-18. 
 
 nil Baumgartner, K. H., Beobachtungen uber "die Nerven und 
 das Blut in ihrem gesundcn und Krankhalten Zustande, February, 
 
THE CELL DOCTRINE. 23 
 
 Arn9ld* (1836), Dutrochett (1837), EaspailJ (1839); 
 all except Hodgkin admitting in greater or less de- 
 gree the importance of the globule as an ultimate phys- 
 ical element ; while it is evident, also, that there 
 was much confusion in the use of terms, the words 
 globule, granule, and ynolecule,^ being often indiscrimi- 
 nately used, and the word globule sometimes used 
 to indicate what is now clearly recognized as the 
 " cell." 
 
 1830. His views are further elaborated in his Beitiage zur Phy- 
 siologic und Anatomie. Aus der Lehre von der Gegensazen in 
 den Kraften in lebenden thierschen Korper, ein Grundriss zur 
 Physiologie und zur allgenieinen Pathologie und Therapie, 2te 
 Auflage, besonders abgcdruikt. Stuttgart, 1842. 
 
 * Arnold, Friedreich, Lehrbuch der Phj'siologie des Menschen. 
 Erst. Thnil, Zurich, 1836. 
 
 f Dutrochet, Memoires pour servir a I'Histoire Anatomique et 
 Physiologique des Vegetaux et des Animaux, t. ii. Atlas. Paris, 
 1837. 
 
 J Raspail, Eechereh. sur la struct, et le developm. de la feuille et 
 du tronc, et sur la struct., etdevel. des tissus Animale, Paris, 1837. 
 
 I The German authors of this period, and even more recent 
 times (Henle, 1841, Virchow, 1858), at least in speaking of the 
 development of histology, seem to use indiscriminately the terms 
 granule or molecule and globule, whereas they s.,v<i morphologically 
 something distinct. A globule is usually held to be a body which, 
 under the microscope, is more or less spherical in form, possessing 
 a bright centre, and dark outline, — the width of this outline being 
 directly as the difference between 'the refracting power of the 
 globule itself and that of the menstruum in which it floats. Thus, 
 the dark outline of a globule of oil floating in water is wider than 
 that of the same globule floating in glycerin. A granule or 
 molecule, on the other hand, is indeterminate in size and shape, and 
 appears as a mere dot under the highest powers of the microscope. 
 It is true that what appears as a granule under a low power, may 
 appear as a globule under a higher. 
 
 / 
 
24 THE CELL DOCTRINE. 
 
 Prochaska * in 1779, described the brain as made 
 up of globules eight times smaller than blood-glob- 
 ules. In the year 1801, the philosophic mind of 
 Bichat elaborated his excellent classification, but he 
 seems to have made no original investigations in 
 minute structure, or to have adopted any special 
 theory of an ultimate physical element. The bro- 
 thers, Joseph and Charles Wenzel,t in 1812, de- 
 scribed the brain as composed of, globules of small 
 size. Among the earliest histologists worthy of 
 mention, is Treviranus,:]: whose elements, according 
 to Ilenle, were first, a homogeneous, formless matter ; 
 second, fibres; third, globules (kiigelchen). Mr. 
 Bauer,§ quoted as a most experienced microscopic 
 observer by Sir Everard Home, in 1818, and again 
 in 1823, described the ultimate globules of the brain 
 and of muscular fibre as of the size of a globule of 
 blood when deprived of its coloring matter, or about 
 j-jjig^ of an inch in diameter. The fibre was excluded 
 as an ultimate element of organization by Heusingeri 
 in 1822-4, who started all tissues from the globule, 
 still, however, retaining the formless material of 
 Haller and Treviranus. Heusinger formed the fibre 
 by the linear apposition of his globular elementary 
 parts, and even explained how canals and vessels 
 were formed by a similar arrangement of vesicles 
 which had originated from the globules. The ac- 
 count given by Henlel" of the method in which Heu- 
 
 * Proschaska, Opera Minora, Part I, p. 342 
 
 ■j- Wenzel, op. citat., p. 24. { Treviranus, op. oitat. 
 
 g Bauer, op. citat. || Heusinger, op. citat., p. 112. 
 
 I' Henle, Allgemeine Anatomie. Leipzig, 1841, p. 128. 
 
THE CELL DOCTRINE. 25 
 
 singer built up his fibres and vessels is interesting 
 and important, since there is in these views an ap- 
 proximation to the truth. "As the result of an 
 equal contest between contraction and expansion, 
 there arises the globule, of which all organisms, all 
 organic parts, are originally composed. By a stron- 
 ger exercise (Spannung, tension) of power, there 
 originates from the often more homogeneous globule, 
 the vesicle. "Where in an organism globules and a 
 formless mass are present, the globules arrange them- 
 selves according to chemical(?) laws and forni_^6res. 
 Where vesicles arrange themselves, there arise canals 
 and vessels." In the latter sentence one cannot fail 
 to note a close approximation to the truth, though 
 the facts upon which the theory was based are partly 
 false and partly misinterpreted. 
 
 But the observations and writings of Milne Ed-'- 
 wards* may be looked upon as having given, more 
 than those of any other author, position and popular- 
 ity to the " globular theory." He examined all the 
 principal tissues, and announced that the fibres of the 
 then so-called cellular (fibrous) tissues, membranes 
 composed of these fibres, muscle and nerve, were 
 composed of globules of about the same size, from 
 B^TTr *° ^bW °^ ^^ inch, in diameter; whence he 
 concluded that these spherical corpuscles, by their 
 aggregation, constituted all organic textures, vege- 
 table or animal, and whatsoever their properties or 
 functions. There is little doubt but that many of 
 these so-called globules described by Edwards were' 
 
 * Edwards, loo. oitat. 
 
26 THE CELL DOCTRINE. 
 
 really cells, seen with itjditterent instruments, and 
 further distorted by the glare of direct sunlight. 
 
 Similar, as regards the element of organization, 
 were the views of Baumgartner* and Arnold,t who 
 were joint observers. 
 
 They considered:]: the fundamental elements of or- 
 ganization to be the formative globule (Bildungskugel', 
 and the molecular granule (Molecular-kugelchen). 
 The first is primarily formed by a simple aggrega- 
 tion of smaller granules first represented by the gran- 
 ules of the yolk united by a formless material. The 
 " molecular granule " arises from a breaking up of 
 the " formative globule." A modification of the 
 " formative globule " out of an aggregation of which" 
 the entire embryo is first formed, is the hsematoid 
 body (Hamatoidkorper). This is a nucleated dis- 
 coid body with a distinct ring-like border (geringtes 
 Korperkern nnt einem Ringe). 
 
 Further, " Out of these two kinds of globules and 
 out of formless material," says Baumgartner, " all 
 tissues are formed, namely, the tissue-fibres (threads) 
 out of the molecular granules, and the hsematoid 
 bodies out of the formative globules and newly- 
 formed tissue-fibres. The molecular form is not 
 everywhere equally expressed, which is owing in the 
 first place to the fact that often the molecular gran- 
 
 * Baumgartner, loe. citat. ; also, Virchow, Cellular Pathology, 
 Am. Ed. of Chance's Translation. Philadelphia, 1863, p. 53. 
 
 t Arnold, loo. citat. ; also, Virchow, Cellular Pathology, Am. 
 Ed. of Chance's Translation. Philadelphia, 1863, p. 63. 
 I % Baumgartner, Beitrage zur Physiologie und Anatomie, 1842, 
 p. 36. 
 
THE CELL DOCTRINE. 27 
 
 ules more or less fuse together, and second, that 
 formless material surrounds the molecular granules 
 and makes their ontline indistinct. The theory here 
 brought forward of the fundamental form of organi- 
 zation in animals may well he called the globular 
 theory." P. 83. 
 
 It is evident that the " formative globule," or at 
 least the modification of it called the Hosmatoidkor- 
 per, is nothing more nor less tlian the nucleated cell, 
 which,however, Baumgartnerdidnot admit, contend- 
 ing as late as 1842 against the cell doctrine ; asserting 
 also (p. 40, op. citat.) that in the development of tissues 
 the formative globule never divides to form two, in 
 other words, that there is no such thing as cell di- 
 vision.* 
 
 Arnold also says thatf all fluid and solid parts of 
 the human body are resolvable first into a fluid or 
 half fluid material of no determinate form, and sec- 
 ond, into granules which are more or less completely 
 spherical-, and in all solid structures appear for the 
 most part as minute globules. The granules, which 
 are the second more important element, occur not 
 only in all fluids and solid parts of the completely 
 formed human organism, but they are also the origi- 
 nal and essential constituents of the human embryo. 
 Out of these by their aggregation are formed the.most 
 complex tissues of the organism. 
 
 * To the student desiring to pursue further this very interesting 
 subject, with the argument against the cell theory by Baumgart- 
 ner, I would recommend the perusal of the very interesting " Bei- 
 trago zur Anatomie und Physiologie " alluded to. 
 
 f Lehrbuoh der Physiologie des Menschen, 1836, p. 82. 
 
28 THE CBIili DOCTRINE. 
 
 The error of these and other observers seems to 
 have been clearly pointed out by Dr. Hodgkin,* 
 though much importance was stHI attached to the 
 
 Fig. 1. 
 
 Illustrating the Globular Theory. 
 
 A, Fibre, composed of elementary granules (molecular granules), drawn up in 
 a line. B, Cell, with spherically arranged granules. (After Virchow, slightly 
 modified.) 
 
 globule as an element of organization (but perhaps 
 from this time forward, more in the stricter sense of 
 the term granule), which has continued, in this latter 
 sense, to the present day. 
 
 It should be mentioned that in 1828 Dollingerf 
 announced that the tissues of the body are built up 
 of blood-corpuscles, which move in wall-less (wandlos) 
 channels in these tissues. 
 
 From the foregoing facts it is evident that for 
 some time prior to the year 1838, the cell had come 
 to be quite universally recognized as a constantly re- 
 curring element in vegetable and animal tissues, 
 though as yet little importance had been attached to 
 it as an element of organization, nor had its charac- 
 ters been clearly determined. As stages in its grow-,- 
 ing importance may be mentioned, the demonstration 
 of the cellular structure of plants by Robert Hooke, 
 
 * Hodgkin, loo. citat. 
 
 t DoUinger, Ignaz, Vom Kreislaufe des Blutes, 1828. 
 
THE CELL DOCTRINE. 29 
 
 in 1 667, the further elaboration of this subject by 
 Malpighi, and his statement that each " utriculus " 
 was an independent entity, the very clear statement of 
 Oken in 1808 with regard to the cellular composition 
 of animals and vegetables, the description of Heusin- 
 ger,in 1822, of the mode of formation of vessels by the 
 apposition of vesicles, already referred to, and the an- 
 nouncement, though erroneous, of DoUinger, in 1828, 
 that the body is built up of blood^corpuscles which 
 move in wall-less (wandlos) channels .in the tissues. 
 
 Haspail, 1837. — Singularly near the truth did Ras- 
 pail* approach, in 1837, when he tells us that in the 
 condition of development there are vesicles or cells, ■ 
 endowed with life and the property, almost unlimited, 
 of producing out of themselves other cells of the same 
 structure and similar endowments, of spherical form, 
 and capable of taking up oxygen when exposed to 
 the atmosphere ; that the cell membrane in its fresh 
 state is structureless. Yet he considers the organic 
 cell as made up of granules or atoms, spirally ar- 
 ranged about an ideal axis, comparing the cell with 
 the crystal, and speaks of organization as crystalliza- ' 
 tion in vesicles (crystallization vesiculaire). 
 
 Dutrochet, 1837. — Similar was the view of Dutro- 
 chet,t who divided the component parts of the body \ 
 into solids anA. fluid. The solids were formed by the 
 aggregation of cells of a certain degree of firmness ; 
 the liquids, as the blood, are also made up of cells 
 which, however, float freely among each other, and 
 there are also tissues in which the cells are so feebly 
 
 * Kaspail, op. citat. f Dutrochet, op. citat. 
 
 3* 
 
30 THE CELL DOCTRINE. 
 
 united, that one can scarcely tell in what class to 
 place them. The contents of the cell may he more 
 or less solid, but the highest degree of vitality is 
 only compatihle with liquid cell contents. Muscular 
 
 fibres, and the remaining animal fibres, are cells much 
 elongated. And he considers the same general plan to 
 prevail in the animal and vegetable. The approach of 
 
 Hboth of these observers to the truth is striking. 
 Both, however, either failed to detect the nucleus or 
 to attach any importance to it. They failed also to 
 lay down a law of organic development, and their 
 views were soon forgotten. 
 
 -y Discovery of the Nucleus, 1833. — A most important 
 contribution to the anatomy of the cell was made be- 
 fore this, however, in the discovery of the "nucleus," 
 by Dr. Robert Brown, of Edinburgh, whose paper, 
 " Organs and Mode of Fecundation in Orchidese and 
 Asclepiadese," appeared in the Transactions of the 
 Linneau Society of London, in 1 833. He failed, how- 
 ever, to appreciate its importance, though its dis- 
 
 j covery was another fact added to those necessary to 
 complete the data on which has been founded the 
 so-called " cell theory." 
 
 Meyen, 1836. — Meyen* sought to establish the 
 opinion that the cell is formed of spiral fibres which 
 lie closely upon one another, founding his view upon 
 his own observation. 
 
 Since the discovery of the nucleus, by Dr. Robert 
 Brown, in the vegetable cell, it had been recognized 
 by many observers in various pathological, as well as 
 
 * Meyen, Pflanzenphysiologie, Bd. i, 1886. 
 
THE CELL DOCTRINE. 31 
 
 healthy animal cells, and in the germ cell or ovule of 
 birds, as early as in 1825, by Purkinje ;* while Pur- 
 kinje,t Valentin,;]: and Turpin,§ had actually called 
 attention to the relations of the animal and vegetable 
 cell to each other. 
 
 The pr'e-existence of the nucleus, and the gradual 
 development of the cell about it, Valentin had at- ^ 
 tempted to demonstrate in the case of pigment cells, 
 C. H. Schultzll in the blood-corpuscle, Rudolph Wag- 
 ner in the egg, and Heule in epithelium, all before 
 the work of Schleiden had appeared. Miiller had 
 also insisted on the analogy between the cells of the 
 chorda dorsalis and vegetable cells.T Valentin, too, 
 had said, when describing the nucleus,of epidermic 
 cells, which he was the first to point out, that they 
 reminded him of the nucleus of the cells of vege- 
 table tissues.** Not only this, but Armand de Qua- 
 trefagesft and Dumortier:j::|: had actually observed the 
 origin of young cells from' the full grown, in the 
 
 * Purkinje, J., Ev. Symtolse ad ovi avium historiatn ante incu- 
 bationem, cum duobus lithographs. Vratis., 1825. 
 
 f Purliinje and Easchkow, Meletemata circa Mammaliura Den- 
 tium Evolutionem. Diss. Inaug. Vratis., 1835, p. 12. 
 
 \ Valentin, TJeber den Verlauf und die Enden der Nerven, aua 
 den Nov. Act. Nat. Curios., vol. xvii ; besonders abgedruckt. Bonn, 
 1836. 
 
 \ Turpin, Ann. d. Sci. Nat., 2 ser. vii, 207. 
 II Sehultz, C. H., Mailer's Archiv fur Anatomie, Physiologie 
 und Wissenschaft. Med., p. cvii, 1837. 
 
 \ Strieker, Manual of Human and Comparative Histology, 
 New. Syd. Soc. Translat., 1870, p. 1. 
 ** Valentin, Nov. Act., N. C. xvii, pt. I, p. 96. 
 +f Quatrefages, Annales des Sci. Nat., 2 ser. ii, p. 114. 
 \% Dumortier, Annales des Sci. Nat., 2 ser. vii, p. 129. 
 
82 THE CELL DOCTRINE. 
 
 embryo of the freshwater snail, while Valentin had 
 furnished examples of the development of fibres 
 out of cells in the muscular fibres, and in the sub- 
 stance of the crystalline lens. In fact, as stated by 
 Dr. Waldo J. Burnett, in his admirable paper,* Val- 
 entin " perceived the true physiological relations of 
 cells as far as he well could without apprehending 
 the grand fact that the nucleated cell is the funda- 
 mental expression of organic forriis." 
 
 Virchow had also compared the whole organism 
 to a free state containing individuals endowed with 
 equal privileges if not with equal powers.f 
 
 SCHLEIDEN AND SCHWANN, 1838. 
 
 It was reserved for Schwann to accomplish this mas- 
 terstroke in observation and generalization, through 
 the intermediate results of Schleiden, without whose 
 observations on vegetable structures, the true position 
 of the cell would probably have remained undetected 
 foi» some time longer. Schleiden, in 1838, clearly 
 pointed out the formation of cells in vegetable struc- 
 tures, according to a single and uniform method, and 
 elaborated the theory of development of which the 
 cell was the unit, and which Schwann immediately 
 extended to animal tissues. 
 
 * Burnett, W. J., The Cell; its Physiolosy, Pathology, and 
 Philosophy, as deduced from original investigations. To which is 
 added its History and Criticism. A prize essay, read before the 
 American Medical Association, and published in vol. vi of its 
 Transactions. Philadelphia, 1853. 
 
 f Strieker, op. citat., p. 2. 
 
THE CELL DOCTRINE. 33 
 
 A formidable obstacle for some time in the vtaj of 
 a law of development, applicable to animal' and vege- 
 table tissues, was the opinion, long entertained, that 
 the growth of animals, whose tissues are furnished 
 with vessels, is essentially difterent from that of plants ; 
 an independent vitality being ascribed to the elemen- 
 tary particles of vegetables growing without vessels. 
 So firmly was this believed, that the ovum, which 
 exhibited undoubted evidences of an actual vitality 
 at one period of its growth, was said by all phj'siolo- 
 gists to have had a plant-like growth. This obstacle 
 was removed in 1837, by Henle,* who showed that 
 an actual growth of the elementary parts of epithe- 
 lium took place without vessels. 
 
 Taking up the nucleus as discovered by Robert 
 Brown, Schleiden,t in reference to its function, ap- 
 plies the name cytoblast {xuto<;, a cell, j^^darvq, a bud 
 or sprout), or " cell bud," and in a careful study of 
 its anatomy, discovers that " in very large and beau- 
 tifully developed cytoblasts, there is observed a 
 small, sharply defined body, which, judging from the 
 shadow which it casts, appears to represent a thick 
 ring, or thick-walled hollow globule."! One, two, three, 
 and even four of these may be present. Without fur- 
 ther present comment than that these characters, as 
 
 * Henle, Symbolae ad Anatumiam vill.intest. Berol., 1837. 
 
 t Schleiden, Beitrage ziir Phytogenesis, MuUer's Archiv, 1838, 
 p. ii ; Contributions to Phylogenesis, Sydenham Soc. Transl., p. 
 233. 
 
 X The term nucleolus or nucleus-corpuscle (Kernkorperehen), 
 seems to have been first applied by Schwann. (See Introduction 
 to Schwann's Researches, Syd. Society's Translation.) 
 
84 THE CELL DOCTRINE. 
 
 given by Schleiden, are by no means constant, it is 
 plain tbat wbat is commonly known as tbe nucleolus 
 is here intended, to tbe discovery of which we are 
 therefore indebted to him, though Valentin also 
 claims its discovery at an earlier period.* He fur- 
 ther states that the observations he has made upon 
 all plants, lead him to the conclusion that these small 
 bodies are found earlier than the cytoblasts. 
 
 According to Schleiden, when starch, which is 
 superfluous nutritive material deposited for future 
 use, is to be employed in new formations, it becomes 
 dissolved into sugar or gum, which are convertible 
 into one another. The sugar appears as a perfectly 
 transparent fluid, not rendered turbid by alcohol, 
 and receiving from tincture of iodine only so much 
 color as corresponds to the strength of the solution. 
 The gum is somewhat yellowish, more consistent, 
 less transparent, and coagulated into granules by 
 tincture of iodine, assuming a pale yellow color, 
 which is permanent. In further progress of organi- 
 zation, in which the gum is always the last inmiedi- 
 ately preceding fluid, a quantity of exceedingly mi- 
 nute granules appears in it, most of which, from 
 their exceeding minuteness, appearing as black points. 
 It is in this mass that organization takes place, 
 though the youngest structures are composed of 
 another distinct, homogeneous, perfectly transparent 
 substance — so transparent as to be invisible when 
 
 * Valentin, "Outline of the Development of Animal Tissues,'' 
 in Wagner's Elements of Physiology, translated by Dr. Willii". 
 London, 1844, p. 214; Leipzig, 1839 ; where he refers to Valen- 
 tin's Eepertorium, vol. i, p. 143. 
 
THE CELL DOCTRINE. 35 
 
 not surrounded by opaque or colored bodies, — and 
 continuing thus after pressure. This substance, which 
 frequently occurs in plants, Schleiden calls vegetable 
 gelatin, and considers as slight modifications, pectin, 
 the basis of gum tragacanth, and many of the sub- 
 stances usually enumerated under the term vegetable 
 mucus. It is this gelatin vphich is ultimately, 
 through the agency of the nucleus, converted into 
 the actual cell-wall, or structures which consist of it 
 in a thickened state, and into the matter of vege- 
 table fibre. 
 
 There are two situations in the plant in which 
 new organization may be observed most easily and 
 clearly, in consequence of there being cavities closed 
 by a simple membrane, Ist, in the large cell, which 
 subsequently contains the albumen of the seed, the 
 embryonal sac, and 2d, in the extremity of the pollen 
 tube, from which the embryo itself is developed. The 
 embryonal sac never contains starch originally, but 
 probably in most instances the saccharine solution or 
 gum. The pollen always contains starch, or repre- 
 senting it, a semi-granulous substance identical with 
 the small granules in the gum above alluded to, which 
 Schleiden calls mucus. 
 
 In both of these situations the above-mentioned 
 minute mwcMs-granules are very soon developed in 
 the gum, upon which the solution, previously homo- 
 geneous, becomes clouded and more or less opaque. 
 
 Single, larger, more sharply defined granules next 
 become apparent, A, Fig. 2, constituting the nucleoli, 
 and soon after the cytoblasts or nuclei, B, appear, look- 
 ing like granulous coagulations about the granules. 
 
36 
 
 THE CELL DOCTRINE, 
 
 Thecytoblasts then grow considerably in the free state, 
 C, but 80 soon as they have attained their full size, 
 a delicate transparent vesicle rises upon their surface, 
 assuming the relation of the watch-crystal to a 
 watch, D, E. This is the young cell, which at first 
 
 Fig. 2. 
 
 B o 
 
 Cellular Tissue, from the embryo sac of Chamsedorea 
 Scbiedeana, in the act of formation. 
 
 A, Formative substance, gum, mucus-granules, nu- 
 clei of oytoblasts (nucleoli). 
 
 B, Cytoblasts. 
 
 C, Single and free cytoblast, more highly magni- 
 fied. 
 
 D, Cytoblast with cell forming in it. 
 
 E, Same, more highly magnified. 
 
 F, Cytoblast isolated after destruction of cell. 
 
 From Schloiden's " BeitrSge zur Phytogenesis." 
 
 represents a very flat segment of a sphere, the plane 
 side of which is formed by the cytoblast, and the 
 convex side by the young cell, which is placed upon 
 it somewhat like a watch-glass of a watch. In a 
 natural medium it is distinguished almost by this 
 circumstance alone, that the space between its con- 
 vexity and the cytoblast is perfectly clear and trans- 
 parent, and probably filled with a watery fluid, and 
 is bounded by the surrounding mucus-granules, which 
 have been aggregated at its first formation, and are 
 pressed back by its expansion, as shown in 1), E. But 
 if these young cells be isolated, the mucus-granules 
 may be almost entirely removed by shaking the 
 stage. They cannot, however, be absent for any 
 length of time, for in a few minutes they become 
 
THE CELL DOCTRINE. SJ 
 
 completely dissolved in distilled water, leaving only 
 the cytoblasts behind. The vesicle gradually ex- 
 pands and becomes more consistent, and with the 
 exception of the eytoblast, which always forms a 
 portion of it, the wall now consists of gelatin. The 
 entire cell then increases beyond the margin of the 
 eytoblast, and quickly becomes so large that the 
 latter at least merely appears as a small body inclosed 
 in one of the side-walls in such a manner that the wall 
 of the cell splits into two laminse, one of which passes 
 exterior and the other interior to the eytoblast. That 
 upon the inner sideis generally the more delicate, and 
 in most instances only gelatinous, and is also absorbed 
 simultaneously with the eytoblast. Within these cells, 
 again, new cytoblasts arise, grow, and form young 
 cells, which grow and fill up the mother cells, and 
 finally cause the latter to disappear., This is endogen- 
 ous ceU formation, while the formation of cells external 
 to other cells constitutes exogenous cell formation. 
 But according to Schleiden -" the entire growth of the 
 plant consists only of a formation of cells within 
 cells."* No other method of formation of new cells 
 seems to have been conceived by him. For although 
 the multiplication of cells, by fissiparous division of 
 previously existing cells, had been demonstrated by 
 Mirbel,t and confirmed by Von Mohl,:^ ^^^ ^^^ ^^g- 
 
 • ? 
 
 * Loo. citat., p. 257. 
 
 f Mirbel, Kecherches sur la Marchantia, 1833. Schleiden, how- 
 ever, says distinctly (op. cit. p. 232), "JVTirbel does not make any 
 allusion to the process of cell formation." 
 
 I Von Mohl, Bntwicklung und Bau der Sporen der Kryptogam. 
 Gew., Flor., 1833. 
 
 4 
 
38 THE CELL DOCTRINE. 
 
 mentation of the egg had been observed even earlier 
 (1824) by Prevost and Dumas, all before the inves- 
 tigations of Schieiden had been made, the latter 
 author considered the apparent growing across of the 
 partition vk'alls an illusion, and that the young cells 
 escape observation in consequence of their transpar- 
 ency, until, at a late stage, their line of contact is re- 
 garded as the partition wall of the parent cell ; while 
 even Schwann states somewhat hesitatingly what is 
 now so generally admitted .* This is the cell theory of 
 Schieiden, which he assumes to be the universal law 
 for the formation of vegetable cellular tissue in the 
 phanerogamia. At that time the cryptogamia had 
 not been examined, and Schieiden had not- then ex- 
 pressed his views in reference to the cambium. 
 
 The merit of Schwann consisted in applying this 
 theory to animal tissues, his conclusions being based 
 upon the study of the formation of the chorda dor- 
 salis and cartilage, and a comparison of their cells 
 with those of vegetable tissues. Thus, in a cyto- 
 blastema, either structureless or minutely granulous, 
 " a nucleolus is first formed ; around this a stratum 
 ■ of substance is deposited, usually minutely granulous, 
 but not yet sharply defined on the outside. .As new 
 molecules are constantly being deposited in this stra- 
 tum between those already present, and as this takes 
 place within a precise distance of the nucleolus only, 
 the stratum becomes defined externally, and a cell 
 nucleus, having a more or less sharp contour, is formed. 
 The nucleus grows by a continuous deposition of new 
 
 ♦ Schwann, op. citat, Introduction, p. 4. 
 
THE CELL DOCTRINE. 39 
 
 molecules between those already existing, that is by- 
 intussusception. (See Fig. 3, e.) If this go on equally 
 throughout the entire thickness of the stratum, the 
 
 Fig. s. 
 
 From the point of a Branchial Cartilage of Kana esculenta. 
 (From Schwann.) 
 
 nucleus may remain solid ; but if it go on more vigor- 
 ously in the external part, the latter will become 
 more dense, and may become hardened into a mem- 
 brane, and such are the hollow nuclei."* 
 
 "When the naeleus has reached a certain stage of, 
 development, the cell is formed around it. The fol- 
 lowing is the process by which this takes place: 
 " A stratum of substance, lohich differs from the cyto- 
 blastema, is deposited upon the exterior of the nu- 
 cleus. (See Fig. 3, d.) In the first instance, this 
 stratum is not sharply defined externally, but be- 
 comes so in consequence of the progressive deposition 
 of new molecules. The stratum is more or less thick, 
 sometimes honfogeneous, sometimes granulous: the 
 latter is most frequently the case in the thick strata 
 which occur in the formation of the rnajority of ani- 
 
 * Schwann, op, citat., p. 175. 
 
40 THE CELL DOCTRINE. 
 
 mal cells. We cannot, at this period, distinguish a 
 cell cavity and cell wall. The deposition of new 
 molecules, between those already existing, proceeds, 
 however, and is so effected that when the stratum is 
 thin, the entire layer, and when it is thick, only the 
 external portion, becomes gradually consolidated into 
 a membrane. The external portion of the layer may 
 become consolidated soon after it is defined on the 
 outside ; but, generally, the membrane does not be- 
 come perceptible until a later period, when it is 
 thicker and more defined internally ; many cells, 
 however, do not exhibit any appearance of the for- 
 mation of a cell membrane, but they seem to be solid, 
 and all that can be remarked is that the external por- 
 tion of the layer is somewhat more compact.* 
 
 " Inmiediately that the cell membrane has become 
 consolidated, its expansion proceeds as the result of 
 the progressive reception of new molecules between 
 the existing ones ; that is to say, by virtue of a growth 
 by intussusception, while at the same time it becomes 
 separated from the cell nucleus The inter- 
 space between the cell membrane and the cell nu- 
 cleus is at the same time filled with fluid, and this 
 constitutes the cell contents. During this expansion 
 the nucleus remains attached to a spot on the internal 
 surface of the cell membrane." Though, according to 
 Schwann, in animal cells the nucleus is never covered 
 by a lamella passing over its inner surface, as is the 
 case with the vegetable cell according to Schleiden. 
 
 * Schwann, op. citat., p. 176. Strieker also informs us (Syden- 
 ham Soc. translation, p. 5) that the corpuscles of mucus and pus, 
 oven in the eyes of Schwann, had no cell-wall. 
 
THE CELL DOCTRINE. 41 
 
 Thus is formed the animal cell according to 
 Schwann, and although its method is very similar to 
 that of Schleiden, hoth as to endogenous and exoge- 
 nous cell formation (for Schwann did not restrict 
 cell genesis to endogenous cell formation), we have' 
 quoted his own paper because he is plainly fuller and 
 more precise in his descriptions. The object of each 
 observer was, however, the same with regard to the 
 Uissues studied; the additional object of Schwann 
 being to show that all organisms,'v{'h&ih%r animal or 
 vegetable, are formed on a common principle, and that 
 this principle is origin from cells, — that the various 
 tissues of the plant and animal, however simple or 
 complicated, are all combinations of these cells, modi- 
 fied in adaptation to the special peculiarities of tis- 
 sues. 
 
 The conception of Schleiden was truly original, 
 though its application was less difficult in conse- 
 quence of the simplicity of vegetable tissues. The 
 conception of Schwann was easier, in being the re- 
 flection of that of Schleiden, while its application 
 was more difficult, in consequence of the great diver- 
 sity of animal tissues ; so difficult that he acknowl- 
 edged that " there are some exceptions, or at least 
 differences, which are as'yet unexplained." This need 
 not surprise us when we recollect that one of the ablest 
 modern exponents of the cell theory admits the diffi- 
 culty of its application to some of the so-called higher 
 tissues.* Indeed, the careful reader of Schwann's 
 
 * Virchow, Cellular Pathologj, Chance's Translation. Am. 
 Edit., Philadelphia, 1863, p. 78. 
 
 4* 
 
42 THE CELL DOCTRINE. 
 
 researches cannot but be surprised at the accuracy of 
 the observations of this histologist, nor can he fail to 
 realize how comparatively few have been the changes 
 necessitated in his descriptions, or the method of ap- 
 plication of his theory to the formation of the differ- 
 ent tissues ; while the portion of the theory of 
 Schleiden and Schwann which does not accord with 
 the latest expression of the cell doctrine, is not so 
 much that which pertains to the formation of tissues 
 from existing cells as that which relates to the 
 method in which they supposed the cells to origi- 
 nate; which, it will be recollected, was by a species 
 of spontaneous generation of the essential parts of the 
 cell, in a homogeneous cytoblastema. 
 
 A difference in the anatomy of the cell as given by 
 Schwann and physiologists of the present day, is 
 seen in the location of the nucleus by the former, 
 who places it not merely eccentrically, but actually 
 "separated from the surface only by the thickness of 
 Ihe assumed cell-wall."* At the present day, the 
 situation of the nucleus, though usually central, is 
 known to be not unvarying. Again, the primary 
 J and absolutely essential presence of the nucleolus, as 
 well as the universal presence of the cell-wall, may be 
 considered characteristics of Schleiden and Schwann's 
 idea of the cell, which are now no longer insisted 
 upon. 
 
 As already stated (p. 38), Schwann would seem 
 to have admitted also, the formation of cells by di- 
 vision, though with some hesitation. Thushewrites:t 
 
 * Schwann, op. citat., p. 87, a. f. 
 
 t Schwann, op. citat., Introduction, p. 4. 
 
THE CELL DOCTRINE. 43 
 
 " A mode of formation of new cells, different from 
 the above described, is exhibited in the multiplica- 
 tion of cells by division of the existing ones ; in this 
 case, partition vs-alls grow across the old cell, if, as 
 Sehleiden supposes, this be not an illusion, inasmuch 
 as the young cells might escape observation in con- 
 sequence of their transparency, and at a later stage, 
 their line of contact would be regarded as the parti- 
 tion wall of the parent cell." 
 
 Schwann believed that the cell-wall was the most 
 active constituent of the cell, that it possessed the 
 power not only of producing physical and chemical 
 changes in its own substance and the cell contents, 
 but of secreting materials from the surrounding sub- 
 stance, and depositing them in its interior, explain- 
 ing in this manner the secretions of glands, the for- 
 mation of fat in some cells, pigment in others, etc. 
 
 It would be easy to point out other defects in the 
 theory of Sehleiden and Schwann, when it is tested 
 by comparison with the more accurate observation 
 of the last twenty-five years, none of which should 
 be permitted to detract from the credit which at- 
 taches to the originators of this conception. It must 
 not be forgotten, that it is no less true of science than 
 of art, that great and important truths in their en- 
 tirety are gradually developed, and that no single 
 mind is capable of elaborating them from their in- 
 cipiency to their complete expression. And as many 
 clever people had daily noticed the rising of steam 
 from the boiling kettle without thinking of utilizing 
 its principles of expansion, so also, many careful ob- 
 servers had time and again witnessed the cellular or 
 
44 THE CELL DOCTRINE. 
 
 vesicular composition of plants, and yet failed to ap- 
 preciate the importance of the-nucleated cell, and to 
 deduce from it a law of development applicable to 
 all organic forms. Again, as the engine of "Watt was 
 far different from the beautiful and powerful crea- 
 tion of the mechanic of the present day, so the cell 
 theory, as developed by Schleiden and Schwann, has 
 been further evolved by later histologists, We 
 may therefore truthfully reiterate, with Prof. Hux- 
 ley, that " whatever cavillers may say, it is certain 
 that histology before 1838, and histology since then, 
 are two different sciences — in scope, in purpose, and 
 in dignity — and the eminent men to whom we allude, 
 may safely answer all detraction by a proud ' circum- 
 spice.' "* 
 
 ,^ According to these observers, then, a perfectly 
 formed cell would be defined as a closed vesicle, with 
 certain contents, among which were essentially a nu- 
 cleolus and nucleus. .. 
 
 HBNLE, BBRGMANN, REICHERT, AND OTHERS, 1840-46. 
 
 It is not consistent with our object to include all 
 of the numerous observations which were multiplied 
 after this period, incited by the researches of Schlei- 
 den and Schwann. It is simply to point out the 
 salient features of those results which point towards 
 and have culminated in accepted views. It has been 
 stated that previous to Schleiden's researches, in 
 1838, the formation of cells by division had been as- 
 serted as one mode of origin, that Schleiden had de- 
 clared this an error of observation, and that Schwann 
 
 * Huxley, op. citat., p. 290. 
 
THE CELL DOCTRINE. 45 
 
 had hesitatingly, if at all, accepted it as a rare 
 method of cell formation. 
 
 Henle,* who, in general, adopted the view of 
 Schwann as to the ■primary origin of cells, though he 
 made exception to its universality of application, 
 says that ceils multiply in three ways: 
 
 1. By budding (durch Sprossen), as in certain lower 
 plants. 
 
 2. By endogenous cell development (durch endo- 
 gene Zeugung), where the cell contents of the mother 
 cell become the cytoblastema of the daughter cells, 
 as originally given by Schleiden and Schwann. 
 
 3. By division or segmentation (durch "Theilung), 
 of which he says, however, no examples are found 
 among animals ; though he also states in the para- 
 graphf immediately following, " We would, with 
 Schwann, consider cell formation in the yolk, by 
 ' furrowing,' an analogous process, if we may con- 
 sider the yolk as a simple cell." He then proceeds 
 to describe how, by a constriction of the surface, the 
 yolk is divided into two equal parts, these into four, 
 and so on until the entire yolk becomes a mulberry 
 mass, made up of little round bodies. This segmen- 
 tation of the ovum already observed in the yolks of 
 frogs, fish, molluscs, and medusse, Henle says at 
 this time (1841), has perhaps merely escaped notice:}: 
 in the case of the higher animals, as plausibly sus- 
 pected by Bergmanu,§ a suspicion which we need 
 
 * Henle, Allgemeine Anatomie. Leipzig, 1841, p. 172 et seq. 
 •j- Henle, op. cit., p. 176. J Henle, op. cit., p. 177. 
 
 J Bergmann, Miiller's Arehiv, 1841. Bergmann also in this 
 paper objected to the existence of a cell membrane, and correctly 
 
46 TBB CELL DOCTRINE. 
 
 scarcely say was amply confirmed a little later. But 
 Henle also states, in the same connection, tbat certaiTi 
 cases arise in which perfect cells are developed in a 
 cytobla8tema,in a manner which is inexplicable, and 
 that from these cells tissues are finally developed.* 
 Whence the undetermined state of the question at 
 that time may be easily inferred. Nor is mention 
 here made by Henle of the nucleus of the cell as the 
 pri mary seat of the segmen tation. The su rface of the 
 cell is said to be " constricted " or " furrowed," deeper 
 and deeper, until the division takes place. This de- 
 scription is still adhered to by many physiologists of 
 the preserit day, who consider that there is a simple 
 disappearance of the germinal vesicle or nucleus of the 
 ovum after fecundation, rather than a division of it 
 into two, and substitution of these for the original one. 
 While endeavoring to trace out the steps by which the 
 present most generally accepted views with regard to 
 the origin of cells were arrived at, it must not be for- 
 gotten that other dissenting views were also ad- 
 vanced, though tending differently from those incor- 
 porated in the text, where it is desired more particu- 
 larly to trace those culminating in existing doctrines, 
 '^hus did Reichertf early (1840), dissent from Schwann, 
 since he failed to find the nucleus universally present 
 in the yolk, and he was the first to defend the view 
 
 maintained that the spheres of segmentation are cells which are at 
 first destitute of a cell membrane, though they become invested by 
 one at a subsequent period. 
 
 * Henle, op. cit., p. 177. 
 
 f Reichert, Das Entwickelungsleben im Wirbelthierreioh. Ber- 
 lin, 1840, pp. 6, 93. 
 
THE CELL DOCTRINE. 47 
 
 that the segments into which the egg breaks tip are 
 cells. Karsten* (1843), published a dissertation upon 
 the cell, in which he stated that cells originate with- 
 out a pre-existing nucleus, and by the expansion of 
 anaorphous granules of organic matter; and more 
 recently (1863), the same author practically reiterates 
 this view, since he says that all " cells of vegetables 
 originate as minute free vesicles in the •fluid contents 
 of previously existing cells," and regards the nucleus 
 as a "small tertiary cell, retarded in its develop- 
 ment."t Again, " when the nucleus is present, the 
 origin of new cells is quite independent of \i"X In 
 addition to the statement already given, Henle also 
 (1843), alleged that some of the so-called fibrous tis- 
 sues were " formed by the aggregation of granules 
 in a certain wa-y without the intervention of true 
 nucleated cells."§ Kolliker,|| one of the foremost 
 exponents of the cell doctrine of the present day, in 
 1844 expressed his dissent from the idea of unity in 
 the mode of cell formation, and states that if there 
 is a single method of cell formation which is in- 
 variable, it remains to be discovered, although he 
 interpreted the segmentation of the germ of ce- 
 phalopods in the same manner as Bergmann. Mr. 
 
 * Karsten, De Cella vitaie Dissertatio. Berlin, 1843. 
 
 f Karsten, Ann. and Mag. of Nat. History, vol. xiii, p. 268. 
 London, 1864. 
 
 X Karsten, Ann. and Mag. Nat. History, vol. xiii, p. 281. 
 
 g Henle, Traite d'Anatomie G^nerale. Trad. d'Allemand, 
 par A. J., Jourdan, 2 vol., Paris, 1843, torn. 1, p. 374. 
 
 II Kolliker, EntwickelungsgeschichtederCephalapoden. Zurich, 
 1844. 
 
48 THE CELL DOCTRINE. 
 
 Paget,* 80 well known from his Lectures on Surgical 
 Pathology, suggested in 1846, that a cell might arise 
 in some other way than from a nucleus, since he had 
 met morbid growths composed entirely of fibres, in 
 which not a nucleated cell was present. Most of these 
 statements are, however, reconciled by the informa- 
 tion which has since been added to our knowledge of 
 the subject. • 
 
 MARTIN BARRY, 1840. 
 
 It was in his first series of erabryological researches, 
 published in Part II of the " Philosophical Transac- 
 tions" of the Royal Society of London, for 1838, p. 
 310, that Dr. Martin Barry declared " that the ger- 
 minal vesicle (which he regarded as the nucleus), and 
 its contents constitute throughout the animal king- 
 dom the most primitive portion of the ovum." In his 
 second series. Part 11, 1839, in stating that the ger- 
 minal vesicle returns to the centre of the cell, post 
 coituni,he first pointed out that'the nucleus does not 
 always accompany the cell through the whole vital 
 process at the periphery (the original position accord- 
 ing to Schleiden and Schwann), but that it also passes 
 to the centre, as we now well know. Here, also, he 
 declares, but in his third series. Part II, 1840, he 
 demonstrates, that there arise in the parent vesicle, two 
 or more infant vesicles, the parent vesicle disappear- 
 ing by liquefaction. And in his third series, p. 529, 
 he says, "The germinal vesicle does not burst, or dis- 
 solve away, or become flattened, on or before the fecun- 
 
 * Paget, Report on the Progress of Anatomy and Physiology, 
 Br. and For. Med. Rev., July, 1846. 
 
THE CELL DOCTRINE. 49 
 
 dation of the ovum as hithei-to supposed. It ceases 
 to be pellucid." And on page 531, "The germinal 
 vesicle fills with cells, and these become filled with 
 the foundations of other cells ; so that the germinal 
 vesicle is gradually rendered opaque." 
 
 He \also describes in this series, in great detail, the 
 mode in which these cells are produced from ' the 
 germinal spot, which he considers in the light of a 
 nucleus to the germinal vesicle. Part II, 1839, p. 
 360. And though the minute details may not pre- 
 cisely accord with those of the most recent observa- 
 tions, the correct idea is clearly grasped. In fact, it 
 may be said that in minuteness of detail alone does 
 he differ from later observers, and had he simply 
 stated that the young cells arise from the nucleus or 
 nucleolus of the parent cell, he would accord pre- 
 cisely with the most recent observers. But he is, if 
 possible, even more explicit when he says, " The pro- 
 cess inherited from the germinal vesicle by its off- 
 spring, reappears in the descendants of these. Every 
 cell, whatever its minuteness, if its interior be dis- 
 cerned, is filled with the foundations of new, cells, 
 into which its nucleus has been resolved." Again 
 he says,* " Schleiden has seen the nucleus undergoing 
 such changes (division), but failed to recognize them." 
 And finally, in " Philosophical Transactions " for 1841, 
 pp. 207-8, we have the following striking paragraphs, 
 which would seem also to correct some previous 
 errors : 
 
 " § 77. I am very much inclined to believe, that 
 
 * Barry, Philosophical Transac, 1840, p. 348, § 385. 
 5 
 
50 THE CELL DOCTRINE. 
 
 in the many instances in which authors on 'cells' 
 have described and figured more than one nucleolus 
 in a nucleus, there has been either an incipient divi- 
 sion of the nucleus into discs, or the nucleus has 
 consisted of two or more discs ; the nucleoli of those 
 authors having been the minute and highly refract- 
 ing cavities or depressions in the discs. If this has 
 really been the case, it afl:brd8 additional evidence, I 
 think, that the reproduction of cells by the process I have 
 described — namely, division of the nucleus of the parent 
 cell — is universal — so numerous have been the in- 
 stances in question. I may refer to the figures given 
 by Schwann, who examined nearly every tissue, and 
 to those of Schleiden, whose observations have been 
 so extensive on plants. I think, indeed, that many 
 of the figures of Schwann aftbrd evidence of the 
 division in question having taken place. It is to be 
 recognized in his delineation of the cells of cartilage, 
 cellular tissue, middle coat of the aorta, muscle, ten- 
 don, feather, etc. The same remark is applicable to 
 a figure given by Reichert of ciliated epithelium 
 cells. Dr. Henle found that in the layers of his 
 ' pflaster-epithelium ' cells, the nucleus, very distinct 
 in the lower cells, had almost disappeared in those 
 situated in the upper part. From this observation, 
 and from the presence of two nucleoli in some of the 
 nuclei figured by this observer, as well as from the 
 nucleus becoming more granular,! think it extremely 
 probable that these cells (including those of the epi- 
 dermis), are reproduced by the process just referred 
 to,— division of the nucleus ; additions being no doubt 
 continuously made at the lower part of the layer, by 
 ' which cells previously there are pushed farther out.' 
 
THE CELL DOCTRINE. 51 
 
 " § 83. The nuclei whicli various observers have 
 found lying among the fibres of various tissues, have 
 been considgred by them as the ' remains of cells.' 
 This may have been the case, but so far from think- 
 ing with those observers, that the nuclei in question 
 were ' destined to be absorbed,' I am disposed to con- 
 sider that they were sources from which there would 
 have arisen new cells." 
 
 Without doubt, we can say, as did Goodsir,* in the 
 above by Martin Barry, we have the " first consistent 
 account of the development of cells from a parent 
 centre, and more especially of the appearance of 
 centres within the original sphere." Nothing more 
 definite, or directly to »the point, could be desired, 
 and we think it may be justly said of Barry, that 
 he completed the expression of the cell theory in- 
 augurated by Schleiden and Schwann, in modifying 
 the mode of origin to conform to most recent obser- 
 vation. 
 
 PROF. JOHN GOODSIR, 1845. 
 
 In 1845, Prof. John Goodsir published his paper on 
 " Centres of Nutrition, "f in " Anatomical and Patho- 
 logical Observations," in which he clearly grasped the 
 two important principles of the modern Cellular Pa- 
 thology ; first, the activity of these centres (nuclei), their 
 power " to draw from the capillary vessels, or from 
 other sources, the materials of nutrition, and to distrib- 
 ute them by development to each organ or texture after 
 its kind ; " second, the origin of such centres or nuclei 
 
 * Goodsir, Turner's Edition of Anatomical Memoirs. Edin- 
 burgh, 1868. Note on p. 390. 
 f Goodsir, op. citat., p. 389. 
 
52 THE CELL DOCTRINE. 
 
 from previously existing nuclei. In this short paper of 
 three pages, are contained, as stated, the essentials of 
 the cell doctrine of Virchow, and as it has recently as- 
 sumed additional interest on controversial* grounds, 
 it may be well to introduce as much as bears directly 
 upon the subject. " The centre of nutrition with 
 which we are most familiar, is that from which the 
 whole organism derives its origin, — the germinal 
 Sfot of the ovum. From this, all the other centres 
 are derived, either mediately or immediately ; and 
 in directions, numbers, and arrangements, which 
 induce the configuration and structure of the being. 
 As the entire organism is formed at first, not by si- 
 multaneous formation of its parts, but by the suc- 
 cessive development of these from one centre, so the 
 various parts arise each from its own centre, this 
 being the original source of all the centres with 
 which the .part is ultimately supplied. 
 
 "From this it follows, not only that the entire or- 
 ganism, as has been stated by the authors of the 
 cellular theory, consists of simple or developed cells, 
 each having a peculiar independant vitality, but 
 that there is in addition, a division of the whole into 
 departments, each containing a certain number of de- 
 veloped cells, all of which hold certain relations to one 
 central or capital cell, around which they are grouped. 
 It would appear that from this central cell, all the 
 other cells of its department derive their origin. It 
 is the mother of all those within its own territory. 
 
 * Edinburgh Monthly Medical Journal, February and April, 
 1869, pp. 766 and 959. 
 
THE CELL DOCTRINE. 53 
 
 It has absorbed materials of nourishment for them 
 while in a state of development, and has passed 
 them off after they, have been fully formed, or have 
 arrived at a stage of growth when they can be de- 
 veloped by their own powers. 
 
 " Centres of nutrition are of two kinds, — those 
 which are peculiar to the textures, and those which 
 belong to the organs. The nutritive centres of the 
 textures are in general permanent. Those of the 
 organs are in most instances peculiar to their em- 
 bryonic stage, and either disappear ultimately or 
 break up into the various centres of the textures of 
 which the organs are composed. 
 
 " A nutritive centre, anatomically considered, is merely 
 a cell, the nucleus of which is. the permanent source of 
 successive broods of young cells, which from time to time 
 fill the cavity of their parent, pass off in certain 
 directions and under various forms, according to the 
 texture or organ of which their parent forms a part." 
 
 Prof. Goodsir does not fail to state in the first para- 
 graph of his paper, that with many of these centres 
 anatomists have been for some time familiar, but 
 further remarks, that with few exceptions they have 
 looked upon them as embryonic structures. He al- 
 ludes in a note to the observations of Bowman and 
 Barry, the former on " Muscle," and the latter " On 
 the Corpuscles of the Blood," in Philosophical Trans- 
 actions, respectively, of 1840 and 1841, and states in 
 a second note that " for the first consistent account 
 of the development of cells from a parent centre, and 
 more especially the appearance of new centres within 
 the original sphere, we are indebted to .Martin 
 
 5* 
 
54 THE CELL DOCTRINE. 
 
 Barry."* We have carefully read the references in 
 each instance. In Bowman's paperf we can recog- 
 nize a brief reference to a possible influence of the 
 cell upon nutrition, but none as to its origin, in the 
 following sentence: "It is, however, not impossible, 
 that in all these cases, there may be during develop- 
 ment, and subsequently, a further and successive de- 
 posit of corpuscles (nuclei) from which both growth 
 and nutrition may take their source." That Dr. 
 Barry's paper is more explicit has been shown. 
 
 REMAK, 1853-55. 
 
 Remak;]: defended most effectually the view that 
 cells originate from previously existing cells by divi- 
 sion, and that at least in the early stages of the de- 
 velopment of the embryo, no other mode of cell devel- 
 opment occurs than by division. Remak also con- 
 tended for, and according to Strieker,§ established 
 the same law in respect to the pathological develop- 
 ment of cells, although Strieker admits also that 
 Yirchow played an important part in the extension 
 of our knowledge in this direction. 
 
 HUXLEY, 1853.11 
 Allusion has already been made to Prof. Huxley 
 
 * Goodslr, Anatomical. Memoirs, yol. ii, p. 889, and note on 
 pp. 390-91. 
 
 ■j- Bowman, " Muscle," Philos. Transac, 1840, pt. i, p. 485. 
 
 X Bemak, Untersuchung ilber die Entwickelung der Wirtel- 
 thiere. Berlin, 1852-55. 
 
 g Strieker, Manual of Human and Corporative Histology. New 
 Syd, Soc. Transl., 1870, p. 84. 
 
 II We presume it will scarcely be inferred by any reader, that 
 
THE CELL DOCTRINE. 55 
 
 in connection with Wolff, of whose theory he has 
 been the able exponent. In the same paper* he has 
 given us his own views — " conceived in the spirit, 
 and not unfrequently borrowing the phraseology, 
 of Wolff and Von Baer." We present them, as 
 far as may be consistent with brevity, in his own 
 words : 
 
 " Vitality, the faculty, that is, of exhibiting defi- 
 nite cycles of change in form and composition, is a 
 property inherent in certain kinds of matter. There 
 is a condition of all kinds of living matter in which 
 it is an amorphous germ — that is, in which its exter- 
 nal form depends merely on ordinary physical laws, 
 and in which it possesses no internal structure. Now, 
 according to the nature of certain previous condi- 
 tions, the character of the changes undergone, or the 
 different states exhibited — or, in other words, the 
 successive differentiations of the amorphous mass 
 will be different. 
 
 " The morphological differentiation may be of two 
 
 the views of Prof. Huxley here presented are brought forward as 
 those now entertained by him, and with which the public have 
 been made so generally familiar through his lecture on "Proto- 
 plasm," or the " Physical Basis of Life," delivered at Edinburgh, 
 November 18th, 1868, and originally published in the " Fort- 
 nightly Review" for February, 1869; but also largely republished 
 in numerous English and American periodicals, as well as in a 
 separate pamphlet, to be had of the publishers of the Yale College 
 Courant, New Haven, Conn. To one closely observing, however, 
 we think that these latter views will appear to be foreshadowed 
 in the theory hero given, and which we think of sufficient his- 
 torical importance to justify its presentation here. 
 
 * Huxley, Eeview of the Cell Theory. Br. and For. Med. 
 Chir. Eev., October, 1853, p. 305. 
 
56 THE CELL DOCTRINE. 
 
 kinds. In the lowest animals and plants, — the so- 
 called unicellular organisms — it may be said to be ex- 
 ternal, the changes of form being essentially confined 
 to the outward shape of the germ, and being unac- 
 companied by the development of any internal struc- 
 ture. 
 
 " But in all other animals and plants, an internal 
 morphological differentiation precedes or accompa- 
 nies the external, and the homogeneous germ becomes 
 separated into a certain central portion, which we 
 have called the endoplast, and a peripheral portion, 
 the periplast. Inasmuch as the separate existence of 
 the former necessarily implies a cavity in which it 
 lies, the germ in this state constitutes a vesicle with a 
 central particle, or a ' nucleated cell.' There is no 
 evidence whatever that the molecular forces of the liv- 
 ing matter (the ' vis essentialis ' of VV'^olff, or the vital 
 forces of the moderns), are by this act of differentia- 
 tion localized in the endoplast to the exclusion of 
 the periplast, or vice versa. Neither is there any evi- 
 dence that any attraction or other influence is exercised 
 hy the one over the other ; the changes which each sub- 
 sequently ondergoos, though they are in harmony, 
 having no causal connection with one another, but each 
 proceeding, as it would seem in accordance with the 
 general determining laws of the organism. On the 
 other hand, the ' vis essentialis ' appears to have es- 
 sentially different and independent ends in view, in 
 thus separating the endoplast from the periplast. 
 
 "The endoplast (nucleus) grows and divides ; but, 
 except in a few more or less doubtful cases, it would 
 seem to undergo no other morphological change. It 
 
THE CELL DOCTRINE. 57 
 
 frequently disappears altogether ; but as a rule it 
 undergoes neither chemical nor morphological meta- 
 morphosis. So far from being the centre of activity 
 of the vital actions, it would appear much rather to 
 be the less important histological element. 
 
 " The periplast, on the other hand, which has 
 hitherto passed under the name of cell-wall, contents 
 and intercellular substance, is the subject of all the 
 most important metamorphic processes, whether mor- 
 phological or chemical, in the animal and plant. By 
 its differentiation, every variety of tissue is pro- 
 duced ; and this differentiation is the result, not of 
 any metabolic action of the endoplasi, which has fre- 
 quently disappeared before the metamorphosis begins, 
 but the intimate molecular changes in its substance, 
 which take place under the guidance of the ' vis 
 essentialis,' or, to use a strictly positive phrase, occur 
 in a definite oi'der, we know not why. 
 
 " The metamorphoses of the periplastic substance 
 are twofold, — chemical and structural. The former 
 {chemical),- may be of the nature either of conversion, 
 — change of cellulose into xylogen, intercellular sub- 
 stance, etc., of the indifferent tissues of embryos, 
 into collagen, chondrin, etc., — or of deposit, — as of 
 silica in plants, of calcareous salts in animals. The 
 structural metamorphoses, again, are of two kinds, 
 vacuolation or the formation of cavities, as in ,the 
 intercellular passages of plants, the first vascular 
 canals of animals ; and fbriltation, or the develop- 
 ment of a tendency to break up in certain definite 
 lines rather than in others." 
 
 These views he illustrates by examples from vege- 
 
58 THE CELL DOCTRINE. 
 
 table life in the sphagnum leaf, and from animal life 
 in connective tissue and striped muscle. 
 
 As characteristic and distinguishing features of 
 this theory, we desire to point out, first, the substi- 
 tution of the term " endoplast " for " nucleus ; " that 
 of " periplast " for " cell-wall," and " intercellular," 
 " substance." Second, the absolutely passive nature 
 of the " endoplast," which is neither itself the author 
 of changes nor the subject of changes. Third, the 
 passive nature. as well of the "periplast," so far as 
 it is the author of changes, though it is pre-emi- 
 nently the subject of changes, the seat in which changes 
 take place. And herein, we believe Huxley to have 
 been misinterpreted by some who have presented 
 his views elsewhere, as Dr. Beale,* who repre- 
 sents him as believing the periplast active, that it is 
 the efficient agent, that it sends in partitions, etc. 
 But that Prof. Huxley considered it passive we be- 
 lieve may be legitimately inferred from his text. 
 As the seat of change, however, accomplished not as 
 " the result of any metabolic action of the endoplast, 
 but of intimate molecular changes in its substance, 
 which take place under the guidance of the vis essen- 
 tialis" the periplast is differentiated into every variety 
 of tissue. Finally, we have the distinct admission, 
 as seen in the sentence last quoted, and also through- 
 out the entire expression of the theory, of a con- 
 trolling, guiding principle, through which the dift'er- 
 
 * Beale, Microscope in Medicine. Third Edition. London, 
 1867, page 147. Beale, Structure and Growth of the Tissues, 
 London, 1865, pp. 9, 10. 
 
THE CELL DOCTRINE, 59 
 
 entiation is accomplished. This principle, which is here 
 referred to as the " vis essentialis," is elsewhere in- 
 cluded under the expressions " vitality," and " general 
 determining laws of the organism." Though this ad- 
 mission is seemingly so at variance with the views of 
 the same observer in 1870, when, in common with 
 other physicists, he emphatically denied the exist- 
 ence of " vital force," or even such a thing as life 
 itself, yet, as already intimated, we deem it possible 
 to detect a foreshadowing of his more modern views, 
 in the following paragraph of the paper whence we 
 have derived our information : 
 
 " We have therefore maintained the broad doctrine 
 established by Wolft", that the vital phenomena are 
 not necessarily preceded by organization, nor are in 
 any way the result or effect of formed parts, but 
 that the faculty of manifesting them resides in the 
 matter of which living bodies are composed, as such ; 
 or, to use the language of the day, that the, vital 
 forces are molecular forces"* 
 
 Huxley moreover says that the three botanical 
 data upon which Schwann's theory was based, viz. : 
 
 1. The anatomical independence of the vegetable 
 cell as a separate entity. 
 
 2. His conception of the structure of the vege- 
 table cell, and 
 
 3. Its mode of development, were all erroneous. 
 Since first, he (Huxley) considers that the fact 
 
 that by certain chemical or mechanical means, a 
 plant may be broken up into vesicles, corresponding 
 
 * Huxley, loc. citat., p. 314. 
 
60 THE CELL DOCTRINE. 
 
 with the cavities which previously existed in it, is of 
 no more value in proving the independence of these 
 vesicles, than the fact that a rhombohedron of spar, 
 broken up with the hammer, into minute rhombohe- 
 drons, is evidence that those minuter ones were once 
 independent, and formed the larger bj their coales- 
 cence. 
 
 Second, Schwann's view of the anatomy of the cell 
 was incorrect, since he regarded the nucleus as in- 
 variably present, whereas in certain vegetable cells 
 (as in Hydrodictyon, Vaucheria, Caulerpa, Sphag- 
 num), it is indubitably absent ; and since he did not 
 include the nitrogenous primordial utricle, discov- 
 ered by Mohl, in 1844,* as one of the elements of 
 the cell. 
 
 Finally, Schwann's mode of cell-development is 
 erronous, having " been long since set aside by the 
 common consent of all observers ; " cell-development 
 always occurring by division, except in the embryo 
 sac of the Phanerogamia, the sporangia of Lichens, 
 and of some Algse and Fungi ; and even the free 
 cell-development of the latter is quite difterent from 
 that of Schleiden and Schwann, being by the develop- 
 ment of a cellulose membrane (periplast) around a 
 mass of nitrogenous substance (endoplast), which 
 may or may net contain a nucleus. 
 
 The difference between the views of Schwann and 
 Huxley are best expressed by the latter in the con- 
 trast he draws between those of Schwann and Wolff: 
 
 * The existence of the primordiul utricle is denied by many 
 botanists of the present day. 
 
THE CELL DOCTRINE. 61 
 
 " For Schwann, the organism is a beehive, its action 
 and forces resulting from the separate but harmo- 
 nious action of all its parts. For Wolff (and Hux- 
 ley), it is a mosaic, every portion of which expresses 
 only the conditions under which the formative power 
 acted, and the tendencies by which it was guided." 
 The statements of Prof. Huxley with regard to 
 cell-development entirely accord with the most recent 
 observations on the subject, and are quite important to' 
 us in tracing out the present state of the cell doctrine. 
 
 J. HUGHES BENNETT, 1855.* 
 
 Dr. Bennett, of Edinburgh, considered that " the 
 ultimate parts of organization are not cells nor nu- 
 clei, but the minute molecules from which these are 
 formed They possess independent physical and vital 
 properties, which enable them to unite and arrange 
 themselves so as to produce higher forms; Among 
 these are nuclei, cells, fibres, and membranes, all of 
 which may be produced directly from molecules. 
 The development and growth of organic tissues is 
 owing to the successive formation of histogenetic 
 and hystolytic molecules. The breaking down of 
 one substance is often the necessary step to the for- 
 mation of another ; so that the histolytic or disin- 
 
 * Bennett's Practice of Medicine. Am. Ed. of William Wood 
 & Co., N. Y., 1866, p. 118. 
 
 Prof. Bennett has further elaborated his views in the Edinburgh 
 Medical Journal, March, 1868, and The Popular Science Review, 
 January, 1869, but his conclusions are substantially the same as 
 quoted. 
 
62 THE CELL DOCTRINE. 
 
 tegrative molecules of one period become the histo- 
 genetic or formative molecules of another." 
 
 Again : " As to development, the molecular is the 
 basis of all the tissues. The first step in the process 
 of organic formation is the production of an organic 
 fluid ; the second, the precipitation in it of organic 
 molecules, from which, according to the molecular 
 law of growth, all other textures are derived either 
 directly or indirectly."* 
 
 Figs. 4, 5, 6, 7, illustrate these views amply. 
 
 Fig. 4. Fig. 5. Fig. 6. Fig. 7. 
 
 Fig. 4, Molecular structure of the scum on its first appearance, in a clear ani- 
 mal infusion. Fig. 5, Molecular structure of the same six hours afterwards. 
 The molecules are separated, and the long ones (so-called vibriones) in active 
 movement. Fig. 6, The same on the second day. Fig. 7, Filaments (so-callid 
 spirilla) formed by aggregation of the molecules, in the same scum on the third 
 and fourth days, all In rapid motion. 800 diam. linear. (From Bennett's Prac- 
 tice.) 
 
 Prof. Bennett contends, also, that morbid growths 
 may easily be shown to originate in a molecular 
 blastema, though not to the exclusion of pre-existing 
 cells. The accompanying figures are sufficiently ex- 
 planatory. 
 
 It should be stated also that this author, in com- 
 mon with others not accepting the cell doctrine in 
 its entirety, admits the production of cells by buds, 
 division or proliferation, without a new act of gen- 
 eration, and that " this fact comprehends most of the 
 admitted observations having reference to the cell 
 doctrine."t 
 
 * Op. citat., p. 119. t Op. cilat., p. 123. 
 
THE CELL DOCTRINE. 
 
 63 
 
 We have in the expression of this theory, a prac- 
 tical admission of the spontaneous origin, of animal 
 life, of which Dr. Bennett, in the paper referred to 
 in the Popular Science Review, for January, 1869, 
 
 Fig. 10. 
 
 Fig. 11. 
 
 Fig. 8, Nuclei imbedded in a molecular blastema. Fig. 9, Young fibre-cells 
 formed by the aggregation of molecules around the nuclei of Fig. 8. Fig. 10, 
 Cancer cells, one with a double nucleus. Fig. 11, Histolytic or so-called granule- 
 cells, breaking down from fatty degeneration. 250 diam. linear. (From Ben- 
 nett's Practice.) 
 
 openly declares himself the advocate, while the views 
 are in no way essentially different from those of 
 Schwann. 
 
 Closely allied to this theory is the so-called in- 
 vestment or cluster theory (Umhiillungs-theorie), de- 
 scribed by Virchow on page 53 of Cellular Pathology 
 (Am. Ed. of Chance's Translation): according to 
 which " originally a number of elementary globules 
 
 Fig. 1?, 
 
 Diagram of the Investment (cluster) theory, a. Separate elementary granules. 
 6, Heap of granules (cluster), c, Granule-cell, with membrane and nucleus. 
 
 existed scattered throughout a fluid, but that under 
 certain circumstances they gathered together, not in 
 the form of vesicular membranes, but so as to consti- 
 tute a compact heap, a globe (mass, cluster — Kliimp- 
 chen), and that this globe was the starting-point of 
 
64 THE CELL DOCTRINE: 
 
 all further development, a membrane being formed 
 outside and a nucleus inside, by the differentiation 
 of the mass, by apposition, or intussusception." 
 
 TODD AND BOWMAN, 1856. 
 
 Notwithstanding earlier approximations to the 
 truth, we find free cell formation still admitted by the 
 eminent authorities, Toddand Bowman, as one mode 
 of origin of cells, so late as December, 1856, though 
 the spontaneous origin of organs is spoken of as ex- 
 ceedingly doubtful. After describing the elements 
 of the ovum, considered in its entirety as a nucleated 
 cell, and referring to the period after fecundation, it 
 is stated, " At this period the embryo consists of an 
 aggregate of cells, and its further growth takes place 
 by the development of new ones. This may be ac- 
 complished in two ways : first, by the development 
 of new cells within the old, through the subdivision 
 of the nucleus into two or more segments, and the 
 formation of a cell around each, which then becomes 
 the nucleus of a new cell, and may in its turn be the 
 parent of other nuclei ; and, secondly, by the forma- 
 tion of a granular deposit between the cells, in which 
 the development of the new cells takes place. The 
 granules cohere to each other in separate groups, here and 
 there, to form nuclei, and around each of these a delicate 
 membrane is formed, which is the cell membrane. The 
 nuclei have been named cytoblasts, because they appear 
 to form the cells ; and the granular deposit in which 
 these changes take place is called the cytoblastema. 
 
 " In every part of the embryo the formation of 
 nuclei and of cells goes on in one or both of the ways 
 
THE CELL DOCTRINE. 65 
 
 above mentioned, and, by and by, ulterior changes 
 take place, for the production of the elementary 
 parts of the tissues."* 
 
 Thus did physiologists adhere to the original free 
 cell formation of Schleiden and Schwann. Singu- 
 larly, Dr. Carpenter,t who expressly states, in his 
 Manual of Physiology, edition of 1865, that he has 
 been led to the view of Professor Beale by compari- 
 son of the results of the recent inquiries of several 
 British and Continental histologists with those of 
 his own studies, says, a few pages further on (p. 150), 
 " JSTew cells may originate in one of two principal 
 modes; either directly from a previously existing 
 cell, or by an entirely new process in the midst of an 
 organizable blastema." He then proceeds to give 
 the two methods in detail, without in any way deny- 
 ing the latter. 
 
 viRCHOw, 1858. 
 
 Less than two years later, August 20th, 1858, 
 Prof. Virchow published his " Cellular Pathology, 
 as based upon Physiological and Pathological His- 
 tology." According to him, the cell is the only 
 possible starting-point for all biological doctrines. 
 This cell can only originate from a previously exist- 
 ing cell, taking its primary origin from the ovum, 
 and the Harveian maxim omne vivum. ex ovo, becomes 
 in its special application, omnis cellula e celluld. This 
 
 * Todd and Bowman, The Physiological Anatomy and Physi- 
 ology of Man. Am. Edit., Philadelphia, 1857, p. 63. 
 
 f Carpenter, Manual of Physiology. London, 1865. Note on 
 p. 14. 
 
 6* 
 
66 THE CELL DOCTRINE. 
 
 is true of all physiological and pathological processes 
 in the vegetable and animal. In all editions of 
 "Cellular Pathology" which we have met, the 
 'typical cell is described as consisting essentially of 
 "cell-wall," "cell contents," and "nucleus;" the 
 " nucleolus," though usually met in fully developed 
 older forms, is not considered an essential constit- 
 uent of the cell. The object of the " nucleus," ac- 
 cording to Virchow, is entirely connected with the 
 life of the cell, that which maintains it as an element 
 and which insures its reproduction. While to the 
 " cell contents " over and above the nucleus, that is 
 the " residual cell contents," is due the function of 
 the cell, that to which is due the contractility of 
 muscle, the neurilityand sensation of nerve, and the 
 secretory office of the gland cell.* 
 
 To secure the universal application of the cell 
 doctrine, it becomes necessary to eliminate from the 
 vegetable cell, the external non-nitrogenous mem- 
 brane, known as cellulose, and restrict it to the nitro- 
 genized portion comprised in the primordial utricle 
 as the proper cell-wall, and in the ■protoplasmic con- 
 tents of the cavity as the proper cell contents, which 
 contain also the nucleus. " It is only when we ad- 
 here to this view of the matter, when we separate 
 from the cell all that has been added to it as an after- 
 development, that we obtain a simple, homogeneous, 
 
 * Virchow, Cellular Pathology, as based upon Physiological 
 and Pathological Histology. Sebond Edition. Translated by 
 Prank Ohance, M.B., etc. Am. Edition, Philadelphia, 1863, p. 
 37. 
 
THE CELL DOCTRINE. 67 
 
 extremely monotonous structure, recurring- with ex- 
 traordinary frequency in living organisms."* 
 
 More recently, however, Virchow is reported as 
 not regarding the " cell-wall " as an essential part of 
 the cell, as stated in Cellular Pathology ; but that a 
 nucleus surrounded by a molecular blastema was suffi- 
 cient to constitute a cell ; then he says that the outer 
 part of this cell blastema consolidates and forms a 
 cell-wall as Beale has shown, and that this takes 
 place in the amoeba when placed in water. f 
 
 As thus defined, the cell is the seat of pathologi- 
 cal and phj'siological processes rather than the blood, 
 or the nerves. The cell is active — the ultimate mor- 
 phological element in which there is any manifesta- 
 tion of life, and beyond which the seat of real ac- 
 tion cannot be removed. Hence the term Cellular 
 Pathology rather than humoral, or neural, or soUd- 
 istic. The so-called exudations are not such in the 
 strict sense of the term, and the cells which they 
 contain, whether of pus or organizable lymph, are 
 the result of proliferation of previously existing cells. 
 Even " fibrin, wherever it occurs in the body exter- 
 nal to the blood, is not to be regarded as an excre- 
 tion from the blood, but as a local production," re- 
 sulting from the activity of the cells of the tissue 
 in which it is found, and conveyed to the surface by 
 the transudation of the serous fluids alone. :[: In the 
 
 * Op. cit.,pp. 31, 34. 
 
 ■j- Letter from Berlin, in Edinburgh MedicalJournal, February, 
 1865. 
 J Virchow, op. cit., pp. 485-6. 
 
68 THE CELL DOCTRINE. 
 
 above statements we have the Jirst distinctive feature 
 of Virchow'e theory. 
 
 Again, since every organized body is usually made 
 up of a number of these cells, each independent in 
 itself, yet combined and arranged for the attainment 
 of a special end, and therefore mutually dependent, 
 there result certain communities or cell territories 
 into which the body is portioned out by Virchow. 
 But not only is the relation of these cells to each 
 and to the central cell whence they took their origin 
 mutually dependent, but in many animal tissues, at 
 least, we have the so-called inter cell alar substance, in 
 a certain definite manner dependent upon the cell 
 or cells which it surrounds, " so that certain districts 
 belong to one cell and certain others to another." 
 Especially is this the case in pathological processes, 
 where sharp boundaries may often be drawn between 
 cell territories. Herein have we the second dis- 
 tinguishing character of Virchow's theory. 
 ^ There are also a third and fourth distinctive fea- 
 tures. It has already been explained that the prin- 
 ciple of the theory of Schleiden and Schwann lay 
 in this, that every tissue, healthy or morbid, results 
 from the apposition of cells, and that this principle 
 is still observed as correct, the mode of origin of the 
 primary cell being alone the object of dispute. Ac- 
 cording to Virchow, however, it is a special cell 
 which becomes the starting-point of physiological 
 and pathological processes, and by its various meta- 
 morphoses constitutes the healthy or morbid tissue, 
 excepting epithelial formations. This cell is the so- 
 called connective tissue corpuscle, or cell of the con- 
 
THE CELL DOCTRINE. 
 
 69 
 
 nective tissue, wMch,, according to Virchow, is a cell 
 with all its essential constituents (cell-wall, cell con- 
 tents, and nucleus), and not a nucleus alone, as origi- 
 nally described by Schwann, and later by Henle* and 
 Landois.t From the well-known universal preva- 
 lence of connective tissue, this view receives support. 
 Thus, it is from the connective tissue corpuscles of 
 the soft, silk-like connective tissue, so universally 
 present in muscle, that the muscular fasciculi are 
 primarily developed. It is from these that^^nerve- 
 
 FlG. 13. 
 
 Fig. l.S. Purulent granulation from the subcutaneous tissue of a rabbit, round 
 about a ligature, a, Connective tissue corpuscles, b, Enlargement of the cor- 
 puscles with division of the nuclei, c, Division of the cells (granulations), d, 
 Development of the pus-corpuscles. X300. (From Virchow.) 
 
 Fio. 14. Interstitial purulent inflammation of muscle in a puerperal woman, 
 m m, Primitive muscular fibres, i i. Development of pus-corpuscles by means 
 of the proliferation of the corpuscles of the interstitial connective tissue. X280. 
 (From Virchow.) 
 
 fibres take their origin. It is by the rapid prolifera- 
 tion of these corpuscles that pus is formed (Figs. 
 13 and 14) ; it is from the perverted growth and de- 
 
 * Henle, Bericht iiber die Fortschritte d. Physiol., 1859 ; 1866, 
 p. 41. 
 I Iiandois, Zeits. f. wiss. Zool., Bd. zyi, p. 1. 
 
70 THE CELL DOCTRINE. 
 
 velopment of these that tubercle and cancer arise 
 (Fig. 15), and similarly all pathological new forma- 
 tions. N'one of these products are exudations from 
 
 
 Development of cancer from connective tissue in carcinoma of the breast, a, 
 Connective tissue corpuscles. 6, Division of the nuclei, c, Division of the cells. 
 d, Accumulation of the cells in rows, e. Enlargement of the young cells and 
 formation of the groups of cells (foci, Zellenheerde), which iill the alveoli of 
 cancer. /, Further enlargement of cells and groups, g, The same development 
 seen in transverse section. (From Virchow.) 
 
 the blood, according to Virchow. They are entirely 
 local in their origin. In these views he is supported 
 by the majority of German observers. 
 
 Another mode of formation of pus is however ad- 
 mitted by Virchow, in the growth and development 
 of new cells in epithelium, whether in cuticle or mu- 
 cous membranes. Whether forms of suppuration 
 exist which may be referred to muscular, nervous, 
 and capillary elements, he considers doubtful. 
 -' A fourth and final distinctive feature of Virchow's 
 views, concerning which there is less unanimity, even 
 among German histologists, is his peculiar system of 
 canals or tubes, produced by the anastomosis of one 
 
/ THE CELL DOCTRINE. 71 
 
 cell with another, aud which he considers must be 
 classed with the great canalicular system of the body, 
 as forming a supplement to the blood and lymphatic 
 vessels, and as filling up the vacancy left by the old 
 vasa serosa, which do not exist.* (See Fig. 16.) Of 
 
 Fio. 16. 
 
 
 Coiinective tissue fronl the embryo of a pig after long-continued boiling. 
 Large spindle-shaped cells, connective tissue corpuscles (Bindegewebeskorper- 
 chen), some isolated and some still imbedded in their basis substance, and anas- 
 tomosing one with the other. Large nuclei with their membrane detached; 
 cell contents in some cases shrunken. X350. (From Virchow.) 
 
 this system he also considers the cordlike fibres of 
 yellow elastic tissue as forming a part.f These he 
 considers, with Donders,:}: as originating by a traus- 
 
 * Virchow, op. citat., p. 76. 
 
 •|- Virchow, op. citat., p. 133, a. f. 
 
 J Donders, Siebold und KolUker's Zeitschrift, Bd. iii. 
 
72 THE CELL DOCTRINE, 
 
 formation of the connective tissue corpuscles them- 
 selves. He says, " The transformation of these latter 
 into the former, can gradually he traced with such 
 distinctness, that there' remains no doubt, that even 
 the coarser elastic fibres directly result from a chemi- 
 cal change and condensation of the walls them- 
 selves.* Where originally there lay a cell, provided 
 with a delicate membrane and elongated processes, 
 there we sec the membrane gradually increasing in 
 
 Fig. 17. 
 
 Elastic networks and fibres from the subcutaneous tissue of the abdomen of 
 a woman, a a, Large elastic bodies (cell bodies), with numerous anastomosing 
 processes. 6 b, Dense elastic bands of iibres on the border of larger meshes. 
 c c, Moderately thiols fibres spirally coiled up at the end. d d, Finer elastic fibres, 
 at e with more minute spiral coils. X300. (From Virchow.) 
 
 thickness and refracting the light more strongly, 
 whilst the proper cell contents continually decrease 
 and finally disappear. 
 
 " The whole structure becomes in this way more 
 
 * Virchow, op. citat., p. 133. 
 
THE CELL DOCTRINE. 73 
 
 homogeneous, and to a certain extent sclerotic, and 
 acquires an incredible power, of resisting the influ- 
 ence of reagents, so that it is only after long-con- 
 tinued action that even the strongest caustic sub- 
 stances are able to destroy it, whilst it completely 
 resists the caustic alkalies and acids in the degree of 
 concentration usually employed in microscopical in- 
 vestigation. The farther this change advances, the 
 more does the elasticity of the parts increase, and in 
 sections we usually find these fibres, not straight or 
 elongated, but tortuous, curled up, spirally coiled, or 
 forming little zigzags (.Fig. 17, c, e). These are the 
 elements which by virtue of their great elasticity, 
 cause retraction in those parts in which they are 
 found in considerable quantity, as, for example, in the 
 arteries. The fine elastic fibres, which are those 
 which possess the greatest extensibility, are usually 
 distinguished from the broader ones, which certainly 
 do not present themselves in tortuous forms. As re- 
 gards their origin, however, there seems to be no 
 difference between the two kinds : both are derived 
 from the connective tissue cells, and their subsequent 
 arrangement is only a reproduction of the original 
 plan. In the place of a tissue consisting of a basis 
 substance and anastomosing reticulated cells, there 
 afterward arises a tissue with its basis substance 
 mapped out by long elastic networks with extremely 
 compact and tough fibres." This may be looked 
 upon as the least well determined of the important 
 points of Virchow's doctrine, though most German 
 histologists also favor it. Among these may be 
 
74 THE CELL DOCTRINE. 
 
 classed Kolliker,* C. 0. \Veber,t Leydig,:j: Fried- 
 reich,! His,! Donders,! Wittich,** Bbttcher,tt Bill- 
 roth41: and Strieker. They are opposed.by Schwann, 
 Reichert, and Henle, and find little favor among 
 English and American histologists. 
 
 A part of this system, also, according to Virchow, 
 are the so-called dentinal tubules, the lacunae and 
 canaliculi of bone, even the continuity traced by 
 Gerlach,§§ between the ciliated cells of the aqueduct 
 of Fallopius; that by HeidenhainU and BriickeTfT 
 between the lacteals and cylinder epithelium of the 
 intestinal villi of the rabbit, by means of corpuscles 
 of connective tissue ; in the epithelium of the endo- 
 cardium by Luschka;*** and the results of similar 
 
 * Kolliker, Manual of Human Microsnopic Anatomy, p. 41, 
 1860. Also recent paper, in which he completely assents to Vir- 
 chow's views, according to N. Y. Quart. J. Pschy. Med., July, 
 1869. 
 f Weber, C. O., Virehow's Archiv, Bnd. xiii-xv. 
 J Leydig, Handbuch der Histologie, 1856. 
 § Friedreich, Virehow's Archiv, Bd. xv. 
 
 11 His, Beitrage zur Normalen und Pathol. Histol. d. Cornea. 
 Basel, 1856. 
 
 ^ Ponders, loc. citat. 
 ** Wittich, Virehow's Archiv, Bd. ix. 
 tt Bottcber, Virehow's Archiv, Bd. xiii. 
 
 11 Billroth, in Beitrage zur Pathol. Histol., 1858, admits all 
 but the tubular nature of the processes, 
 ^g Gerlach, Mikrosk. Studien, 1858. 
 
 III! Heidenhain, Molesohott's Untersuchungen, Bd. iv, 1858, p. 
 261. 
 
 f1[ Briioko, Moleschott's Untersuchungen, Bd. viii, 1862, p. 495. 
 *** Luschka, Virehow's Archiv, Bd. ix, p. 569. 
 
THE CELL DOCTRINE. 75 
 
 observations by Eckbart* Billrotb,t and Fried- 
 reicb.J 
 
 The other fibrous element of areolar or connective 
 tissue, which forms the mass of its bulk, the pure 
 vjhite fibrous or waving, does not, according to Vir- 
 chow, have its origin in cells, but is a modification 
 of a previously homogeneous intercellular substance, 
 deposited between the cells; a view which in its glar- 
 ing departure from the primary proposition that the 
 cell is the starting-point, and that every tissue is 
 composed of cells or some modification of cell forms, 
 presents one of the few inconsistencies traceable in 
 the theory of Virchow. 
 
 We think it proper, in a historical memoir of this 
 kind, to refer to some severe critical remarks vt'hich 
 appeared in the Edinburgh Medical Journal, of Feb- 
 ruary and April, 1869, in which Prof. Virchow is ac- 
 cused of appropriating the observations of Prof. 
 Groodsir as his own. That there are points in com- 
 mon, it will be recollected, and, also, that these are 
 1st, the invariable origin of cells from previously ex- 
 isting cells, and 2d, the division of the tissues into 
 cell territories. Now on the one hand we deem that 
 the dedication of Virchow's volume to Prof. Goodsir 
 is as handsome an accredit as could possibly be given 
 for whatever of common there may be in the writings 
 of the two authors, and on the other hand we have 
 seen that Martin Barry is acknowledged even by 
 
 * Eckhart, Beitrage Anat. und Physiol., 1855. 
 f Billroth, Mailer's Archiv, 1858. 
 J Friedreich, loc. citat., p. 538. 
 
76 THE CELL DOCTRINE. 
 
 Goodsir, to be the author of the " first consistent 
 accoun.t of the development of cells from a parent 
 centre." The idea of cell territories seems, however, 
 to have originated with Goodsir, nor do we believe, 
 for the reason stated, that Virchow intended to usurp 
 his prerogative. The merit of Virchow consists in 
 his application by actual demonstration of the first 
 of these points to so large a variety of physiological 
 and pathological processes, to which is added original 
 conception in the prominence given to the. connec- 
 tive tissue corpuscle and the canalicular system, 
 whatever may be the truth with regard to. either. 
 
 SARCODE OF DUJARDIN — PROTOPLASM OF MAX SCHULTZE. 
 
 1835-61.- 
 
 Dujardin* had, in 1835, discovered in the lower 
 animals a living, moving, contractile substance, 
 which he called sarcode. The peculiar appearances of 
 this substance ..attracted the attention of many ob- 
 servers, among whom were Kiihne, Eeichert, Ecker, 
 Henle, Meyen, Huxley, Max Schultze, John Miiller, 
 and others. ■ It was thought peculiar to the lower 
 animals, and there was assigned to it a property of 
 "irritability without nerves."t ' 
 
 The observation of Siebold,:]: that the yolk glob- 
 ules (vitelline spheres of the egg) of Planaria exhibit 
 contractions and expansions, which with suitable 
 care continue for hou rs, and the discoveries which fol- 
 
 * Dujanlin, Ann. d. Sciences Nat., torn, iii et v. 
 f Schultze, Max, Organis. d. Polythalamien, 1854. 
 X Siebold, Froriep'a Notizen, Nr. 880, p. 85. 
 
THE CELL DOCTRINE. 77 
 
 lowed of similar movements and changes in form, in 
 colorless blood-corpuscles, pigment cells, arid else- 
 where, led Kblliker* to express the conjecture that 
 the contents of all cells are contractile. Virchowf 
 attributed' the ciliary movement to a contractile sub- 
 stance. Leydig:]: and Ecker considered the move- 
 ments of the yolk spherules as phenomena of life, 
 and Kiihne§ had studied physiologically and chemi- 
 cally, sarcode and muscular tissue, and pointed out 
 the similarity of the phenomena presented in the act 
 of dying, by both. But all considered sarcode as 
 something difterent from the animul cell, as a body 
 sui generis. 
 
 According to HseckelH the protoplasm or sarcode 
 theory, that is, the theory that the albuminous con- 
 tents of animal and vegetable ceils as well as the 
 freely moving sarcode of Rhizopoda, Myxomycetse,. 
 etc., are identical, and that in both cases this albu- 
 minous material is the original active substratum of 
 all vital phenomena, was brought forward in its ele- 
 mentary form by F. Cohnl" in 1850, and by linger in 
 1855.** Hseckel says also that it may be considered 
 one of the greatest achievements in modern biology 
 and one of the richest in results. It was further dc- 
 
 * Kolliker, Wurzb. Verb., Bd. viii. 
 f Virohow, Archiv, Band v., 1858. 
 J Leydig, Handbuoh der Histologie, 1856. 
 g Kuhne, Miill. Archiv, 1859, p. 817. 
 II Quart. J. Mic. So. July, 1869, p. 223. 
 
 ^ P. Cohn, Naohtrage zur Naturgeschiohte des protococous plu- 
 vialis, Nova Acta Ac. Leop. Carol., vol. xxii, pars. 2, 1850, p. 605. 
 ** linger, Anatomie und Physiologie d. Pflanzen, 1855. 
 
 7* 
 
78 THE CELL DOCTRINE. 
 
 velopecl by Max Schultze in 1858, and finally estab- 
 lished by him in 1861.* He first showed the anal- 
 ogy between sarcode and the contents of the animal 
 cell, and that the entire infusorial world, simple or 
 compound, is made np of cells, thus extending the 
 typical formative element of Schwann to the entire 
 organized creation. 
 
 The comparison between sarcode and the proto- 
 plasm of plants on the one hand, and that of animal 
 cells on the other, was also made by PringBheim,f 
 E. Brueke,t E. H8eckel,§ and W. Kiihne,l| and by 
 their eftbrts, together with those of Max Schultze, 
 linger, and Cohn, our knowledge of the indepen- 
 dent life of the cell was extended, in a very short 
 space of time, further than in the twenty years pre- 
 vious.Tf 
 
 The name protoplasm ior a portion of the contents 
 of the animal cell had already been brought into use 
 by Remak, who extended it from the layer which 
 bore that name in the vegetable cell to the analogous 
 element in the animal cell.** 
 
 * Schultze, Max, Mull. Archiv, 1861, p. 17. 
 
 ■j- Pringsheim, Untersuchungnn iiber d. Bau. u. d. Bildung d. 
 Pflanzenzellen, 1854. 
 
 X Briicke, E., Elementar-organismen, Wien. Sitzungsb., 1861. 
 
 § Hseckel, E., Die Radiolaren, 1862. 
 
 II Kiihne, W., Protoplasm und die Contractilitat. Lpzg.,1864. 
 
 Tf Strieker, S., Handbuch der Lehre von den Geweben des 
 Menschen und der Thiere. Leipzig, 1868, p. 8, German Ed. 
 ** Sterling, J. H., As regards Protoplasm in relation to Prof. 
 Huxley's Essay on the Physical Basis of Life. Edinburgh, 1869, 
 p. 14. Conf. also McNab, Monthly Mioroso. J., No. xvii, vol. 
 iii, 1870, p. 33. 
 
THE CELL DOOTKINB. 79 
 
 Pringsheim had also shown, in 1,854, that no such 
 memhrane as a primordial utricle existed, hut that 
 all. within the cellulose wall of the living vegetable 
 cell was protoplasm and cell fluid, however complex 
 its composition. 
 
 " He admitted that in the cortical layer of the pro- 
 toplasma a distinct arrangement into layers often 
 occurred, and these he distinguished as the cutaneous 
 and granular layers of the protoplasnia, but he de- 
 nied that the primordial utricle could be differen- 
 tiated as a membrane from the subjacent protoplasm. 
 If, in animal cells, partly from their relatively small 
 size, and partly from their greater average wealth in 
 protoplasraa, it is more rarely possible to make a 
 sharp demarcation between a cortical layer of pro- 
 toplasm and a cell fluid, there' nevertheless exists a 
 difference in the constitution of the former, such 
 that a cutaneous layer, destitute of or scantily sup- 
 plied with granules, incloses the remaining more 
 granular material. The white blood cell may serve 
 as an example. This is, however, very different, from 
 a proper membrane."* 
 
 Ungerf (1855), had been struck with the close 
 similarity of the mobile phenomena of the Poly tha- 
 lamic with those of the processes of protoplasm 
 stretched across the. cavity of many vegetable cells. 
 Although he had not personally investigated the for- 
 mer, he became convinced from Schultze's description 
 that a resemblance amounting to identity existed 
 
 * Duffin, A. B., On Protoplasm. Quart. Jour. Mio. Soi., N. 
 S., vol. iil, 1863, p. 252. 
 + Unger, op. cital., p. 280. 
 
80 THE CELL DOCTKINE. 
 
 t 
 
 between their movements and the protoplasm streams 
 of vegetable cells.* 
 
 Leydig,t in 1856, claimed for the contents of the 
 cell a higher dignity than for the membrane or cell- 
 wall. He claimed that a cell was but frotoptasm 
 (klumpchen-substanz) inclosing a nucleus. The cell 
 membrane, according to him, was simply the hard- 
 ened periphery of the substance of the cell. 
 
 To Max Schultze, however, as already stated, be- 
 longs the credit of having fully overturned the vesic- 
 ular idea of cells. In 1861,:}: he insisted upon some 
 modification of prevailing views, respecting the rela- 
 tion of cell-wall to cell contents, and contended for a 
 higher position for that part of the cell correspond- 
 ing to the protoplasm of Von Mohl (that within the 
 so-called primordial utricle), and showed how a care- 
 ful study of the phenomena presented by the pseado- 
 podia, extended by the various Rhizopods, might aid 
 in clearing up the life of the elements of the cell. 
 
 He also defined the cell as " protoplasm surround- 
 ing a nucleus." The importance of this definition, 
 as stated by Stricker,§ lay not so much in the fact 
 that many cells were denied a cell-wall, as that 
 the so-called cell contents could now be made to har- 
 monize with the animal primordial substance or sar- 
 code. Schultze illustrates his definition by the em- 
 
 * Duffin, A. B., loo. citat., p. 262. 
 f Leydig, op. citat. 
 
 % Schultze, Max, Ueber Muskelkorperchen, in Beichertand Du- 
 bois Eeymond's Archiv, 1861. 
 
 g Strieker, op. citat., 5. (German Ed.) 
 
THE CELL DOCTRINE. 81 
 
 bryo cells resulting from the segmentation of the ovum, 
 as typical cells, which are thus composed of proto- 
 plasm surrounding a nucleus, which nucleus, as well 
 as protoplasm, are products of like constituent parts 
 of another similar cell. "The cell leads in itself an 
 independent life, of which the protoplasm is espe- 
 cially the seat, although to the nucleus also undoubt- 
 edly falls a most important, though not yet precisely 
 determined role. Protoplasm is for the most part 
 no further distinct than that it will not commingle 
 with the surrounding medium, and in the peculiarity 
 that with the nucleus it forms a unit. Upon the 
 surface of the. protoplasm, there may form a mem- 
 brane, which, although derived from it, may he chemi- 
 cally different, and the assertion that it is the begin- 
 ning of a retrogression may be defended. A cell with 
 a membrane cannot divide .itself, unless the proto- 
 plasm within the membrane divides itself. A cell 
 within a membrane chemically different from proto- 
 plasm, is like an encysted infusorium."* 
 
 Briickef went even further in his definition, and 
 said that it was not shown that the nucleus even is 
 an essential element of the cell. In proof of which 
 he adduces the cells of cryptogams and says: "We 
 have no positive knowledge either of the origin or 
 function of the nucleus, and, indeed, the constancy 
 of its occurrence seems subject to certain limitations 
 if we take into consideration the ceils of cryptogams, 
 
 » Schultze, Max, Protopl. d. Bhizopoden. Leipzig, 1863. 
 j- Bi'iiclte, B., Die Elementar-orgiinisraen, p. 18-22. 1861. 
 
82 THE CELL DOCTRINE. 
 
 and do not start out with the belief that the nucleus 
 is there even though wo do not see it." Facts iu 
 justification of Briicke's doubt are adduced by 
 Strieker* in the discovery by Max Schultze,t in the 
 Adriatic Sea, of a non-nucleated amoeba (Amoeba 
 porrecta), by Hseckel,:]: in the Mediterranean, of a 
 non-nucleated protozoon (Protogenes primordialis), 
 and by Cienkowsky§ of two non-nucleated monads, 
 namely, Monas amyli and Protomonas ainyli. Hsec- 
 kel says of his Protogenes primordialis that it mul- 
 tiplies by division. Stricker's|| own observations on 
 the fecundated egg of the frog, which confirm those 
 of Von Baer, incline him to adopt the view of Briicke, 
 and to omit the nucleus in a theory of elementary 
 organization.Tf 
 
 Such is the history of and such the properties of 
 the substance known as " protoplasm." But of late 
 
 * Strieker, op. citat., p. 6. (German Ed.)' 
 
 f Sehultzfe, Max, Organis. d. Polythalam. 185i. 
 J Hseckel, Zeitschr. f. w. Zoolog., 1865, Bd. xv. 
 
 I Cienkowsky, Max Sehultze's Archiv, 18G5. 
 
 II Strieker, op. citat.. New Sydenham Society's Translation, 
 vol. i, p. 8, London, 1870. See also Strieker's paper On the De- 
 velopment of the Simple Tissues, in vol. iii, London, 1873. 
 
 ][ Hseckel' also considers that by no phenomena is the correct- 
 ness of the " protoplasm theory" so thoroughly proved, and at the 
 same time in so simple and unassailable a manner, as by the vital 
 phenomena of the Monera, by the processes of their nourishment 
 and reproduction, sensitiveness and motion, which entirely pro- 
 ceed from one and the same very simple substance, a true " primi- 
 tive slime." 
 
 * Heeckel, Ernst, Monograph on the Monera, and Kemarks on the Protoplasm 
 Theory. Q. Jour. Mic. Soi., N. S. vol. ix, 1869. 
 
THE CELL DOCTRINE. 83 
 
 years another meaning has heen given to the term, 
 an anatomical one, in which the original general ap- 
 plication has been altogether ignored, and that is 
 that part of the cell outside of the nucleus without re- 
 gard to the properties of the matter, corresponding 
 to the "cell contents " in cells which have a cell-wall. 
 Thus we speak of the protoplasm of the colorless 
 corpuscle or the liver-cell, or of the squamous epithe- 
 lial cell, whereas the properties of the substance thus 
 named are vastly difterent. In the former two in- 
 stances living growing matter is meant, in the latter 
 dead formless material, incapable of growth and re- 
 production through its own inherent properties. 
 l"hese differences should be always remembered. 
 
 With these general considerations in the history 
 of " protoplasm," we are the better prepared to take 
 up the theory of 
 
 DK. BEALE, 1861. 
 
 , In April and May, 1861, Prof Lionel S. Beale de- 
 livered the lectures before the Royal College of Phy- 
 sicians of London, in which he promulgated the 
 views which have since been further elaborated and 
 become permanently associated with his name. These 
 views were published in part, in Beale's " Archives 
 of Medicine," and in September, 1861, in a volume 
 " On the Structure of the Simple Tissues of the 
 Human Body," in the preface to which he says, " he 
 thinks it right to state that the conclusions which 
 have now assumed a definite form have gradually 
 grown upon him during the course of observations 
 
84 THE CELL DOCTRINE. 
 
 extending over a period of several years. In fact 
 some of the drawings in this volume, and others 
 vi'hich have "been published elsewhere, equally favor- 
 able to this view, were made long before any specific 
 theory had been arrived at." 
 
 'The " cell" or " elementary -part" as Dr. Beale pre- 
 fers to call it, is composed of matter in two states, 
 matter which \s forming, and matter which is formed ; 
 matter which has the power of growing by produc- 
 ing matter like itself out of pabulum or food, and 
 matter which possesses no such power, but results 
 from the death of the forming matter. The former 
 is known as germinal or living matter, the latter as 
 formed matter. The former, in varying quantity in 
 diiferent cells, is central in its situation (see frontis- 
 piece. Fig. 17), and includes what, has been called by 
 others nucleus, cell contents, protoplasm, endoplast. 
 The latter, also present in different quantity in differ- 
 ent cells, is peripheral (frontispiece, Fig. 17), and in- 
 cludes what is known as cell-wall, periplast, inter- 
 cellular substance, and products ot secretion. 
 
 In its structural characters, germinal matter is soft, 
 transparent, colorless, and as far as can be determined 
 by the highest powers, structureless, being visible 
 only through its difference in refracting power as 
 compared with the menstruum in which it floats, or 
 by the granular matter it may entangle ; and these 
 characters are the same at every period of its exist- 
 ence. In the simplest vegetables they may be studied, 
 in the thallus of the sugar fungus, among the lowest 
 animals, in the amoeba (frontispiece, Fig. 16), and in 
 higher animals in the mucus-, pus-, or white blood-cor- 
 
THE CELL DOCTRINE. 85 
 
 puscles (frontispiece, Fig. 10), all of which are com- 
 posed almost purely of germinal matter ; the very thin 
 periphery of formed material being scarcely appreci- 
 able or distinguishable from the diffraction band. 
 
 In its endowments and 'properties, germinal matter 
 is acting, living, growing, and moving^ through some 
 inherent power of its own. It alone, as stated, is 
 capable of producing material like itself out of pabu- 
 lum, and of multiplying by division, or dropping off 
 of a portion of itself, which portion immediately 
 assumes an independent existence, and grows, main- 
 tains, and reproduces itself like the parent germinal 
 matter. It is also capable of being stained by an 
 ammouiacal solution of carmine, and the younger it 
 is, or more recently formed, the deeper is the stain it 
 assumes. And since the latest formed always ap- 
 pears in the centre of the mass, successive tints, or 
 zones of color, will often be produced in the staining 
 process, growing deeper from without inward, as 
 seen in Fig. 17 of the frontispiece. 
 
 It has been stated that what is called nucleus by 
 Virchow and others, is included in germinal matter. 
 This is true, though the nucleijs is not always the 
 whole of the germinal matter. There may be other 
 older germinal matter beyond the nucleus, on its 
 way to conversion into formed material, but still 
 germinal matter, which assumes a tint with carmine, 
 but not so deep as the nucleus. Thus, the entire mass 
 of the pus-corpuscle (frontispiece. Fig. 10), except, 
 perhaps, its extreme periphery, is germinal matter, 
 yet there is within this another younger portion of 
 germinal matter, taking a deeper tint with carmine, 
 
86 THE CELL DOCTRIN-B. * 
 
 but which alone of the elements of this cell we are in 
 the habit of calling " nucleus." The " nucleus" then, 
 is nothing but a new centre of germinal matter, and 
 the " nucleolus " is a younger centre. And there may 
 even be within this a still younger portion of living 
 matter, taking even a deeper stain, which might be 
 called a " nucleoleolus." By this staining process may 
 we distinguish the nucleolus from a minute oil-drop 
 often mistaken for it, and which will not admit of 
 being stained. 
 
 On the other hand, germinal matter in a compar- 
 atively quiescent state is often quite destitute of 
 nuclei. But let the mass be freely supplied with nu- 
 trient matter, and nuclei and nucleoli rapidly make 
 their appearance. 
 
 So with regard to the " cell contents " over and 
 above the nucleus, although they may all be germinal 
 matter, yet this is not necessarily the case. Thus 
 in the white blood-corpuscle and mucus-corpuscles, 
 what Virchow would consider cell contents is all ger- 
 minal matter ; but the superficial epithelial cell lining 
 the interior of the mouth has its nucleus alone com- 
 posed of germinal matter, and much that has been 
 described as cell contents is really formed matter. 
 (Figs. 5 and 6 of frontispiece.) More nearly does the 
 germinal matter of Beale* correspond with the "proto- 
 plasm " of Max Schultze, with which , indeed , it seems 
 identical, except that the latter observer seems some- 
 what at a loss how to dispose of the nucleus, of 
 
 * Beale, Protoplasm; or, Life, Force, and Matter. London, 
 1870, p. 38. 
 
THE CELL DOCTRINE. 87 
 
 which he does not speak as a new or young centre 
 of protoplasm. 
 
 Formed material, instead of being active, so far as 
 the vital acts described as characteristic of germinal 
 matter are concerned, is 'passive, non-acting, dead, and 
 can only increase at the expense and death of the 
 germinal matter, on the periphery of which it is 
 formed. It difters widely in its appearance, and is 
 often " structured " as in muscle and nerve, but not 
 necessarily so, as is seen in^the intercellular sub- 
 stance of hyaline cartilage. It possesses also cer- 
 tain properties, different in different situations, and 
 widely different also from those of germinal matter. 
 Thus it is contractile in the sarcous tissue of muscle, 
 exhibits neurility in the nerve, is protective in epi- 
 thelium, is diffluent as the formed material of the 
 milk-cell (milk), and in the formed material of the 
 liver-cell (bile). Again, it is hard and elastic in the 
 intercellular substance of cartilage and epidermis, 
 horn and nails. It does not become stained on being 
 soaked in weak solution of carmine in ammonia, and 
 if by reason of the strength of the solution it should 
 happen to be stained, the color will wash out on 
 soaking in glycerin, which is not the case with the 
 coloring of the germinal matter. 
 
 The cause of this permanent staining of the ger- 
 minal matter by an ammoniacal solution of carmine, 
 is thought by Dr. Beale to be due to an acid reaction 
 of this matter, in consequence of which the carmine 
 is precipitated from its alkaline solution. This view 
 would seem to be confirmed by the researches of 
 Eanke on the Beaction of the Tissues. 
 
88 THE CELL DOCTRINE. 
 
 The size of the elementary part, as thus composed, 
 is extremely various. The smallest' particles of ger- 
 minal matter, measured by Dr. Beale, are less than 
 j-^jI-^-^-^ of an inch in diameter, and would not be 
 called cells in the ordinary sense of the word, yet 
 they are functionally such ; that is,. they grow, multi- 
 ply by division, and under appropriate circumstances 
 assume the characters of fully formed cells. On the 
 other hand, the largest epithelial cells, including 
 their germinal matter and formed material, are often 
 as large as the ^ Jjj of an inch in diameter, or larger ; 
 cells of morbid growths are sometimes ^J,,, while the 
 hunian ovum, which is a typical cell, varies from the 
 s^-g- to Tin of an inch. .Pure germinal matter is 
 rarely seen in masses as large as the jj^ of an inch 
 in diameter, without breaking up into smaller par- 
 ticles of germinal matter, and as constituting the 
 nuclei of fully formed cells, is usually from g^'^j- to 
 ^^0 5 of an inch in diameter. 
 
 The method of ■production of formed material is best 
 studied in the epithelial structures, particularly in 
 the epithelium lining mucous cavities, of which sec- 
 tions may be easily made down to the vessels whence 
 their nourishment is obtained. In the deep layers, 
 next the nutrient surface, the cells will be found to 
 consist of almost pure germinal matter (frontispiece, 
 Fig. 1), imbedded in a soft, mucus-like, yet continuous 
 formed matter. These masses of germinal matter 
 divide and subdivide, pushing the older masses to- 
 wards the surface, to make up for those which are 
 constantly exfoliated. While this is going on, how- 
 ever, the germinal matter keeps increasing in size 
 
THE CELL DOCTRINE. 89 
 
 until the cells arrive half way towards the surface, 
 by absorption of nutrient pabulum, which has to dif- 
 fuse itself through any formed material already ex- 
 isting. At the sarrie time, a portion of the germinal 
 mattei' is being converted into formed material, 
 which accumulates on its surface, within that already 
 formed, stretching it, and becoming more or less in- 
 corporated with it. Thus, both constituents of the cell 
 increase up to a certain point, the cells constantly growing 
 in consequence. As new cells are, however, produced 
 from below," the older ones are removed farther and 
 farther away, the formed matter becoming more and 
 more impervious to nutrient pabulum. At length a 
 point is attained when the entire cell ceases to in- 
 crease in size, since no pabulum reaches the masses 
 of germinal matter, though the latter is still being 
 converted into formed material. Hence, the masses 
 of germinal matter actually grow smaller as the cell 
 increases in age ; and when the periphery is reached, 
 there remains but a small nucleus of germinal matter, 
 with a large quantity of formed material. Thus, we 
 are enabled to judge of the age of the cell by the 
 relative quantity of germinal matter and formed 
 material ; if the former be large, and the latter small, 
 the cell is young, whereas, if the opposite relation 
 exists, the cell is old and almost ready to exfoliate. 
 But exfoliation in health probably does not take 
 place until the last particle of germinal matter dies, 
 and the entire cell becomes a mass of passive, life- 
 less, formed material. 
 
 The production of formed material from germinal 
 matter may also be studied in the conversion of the 
 
90 THE CELL DOCTRINE, 
 
 white blood-corpuscle into the red. In the spring of 
 the year many white corpuscles can be found in the 
 blood of the frog and newt, undergoing conversion 
 into formed material at their edges, where the usual 
 granular appeara'nce is being substituted by the 
 smooth and slightly colored. This goes on until all 
 except the nucleus is thus converted. In mammalia 
 this change goes on until the whole white corpuscle 
 is thus converted into the red. 
 
 Secondary Formed Material. — There are certain 
 kinds of formed material to which this term is ap- 
 plied by Dr. Beale. These are the oil of the fat-cell 
 or vesicle and the starch-granule of the vegetable 
 cell. It results, as does all formed material, by a con- 
 version of the germinal matter into this special form. 
 The young fat-cell, as all young cells, is almost pure 
 germinal matter ; as it grows older, however, and is 
 exposed to oxidizing influences, the conversion of 
 germinal matter takes place, partly into the cell-wall 
 proper of the fat-vesicle, and partly into the second- 
 ary formed material or oil, until finally it becomes a 
 mere dot on the inner surface of the cell-wall, or dis- 
 appears altogether. 
 
 The increase of cells, according to Beale, takes place 
 in several ways ; every cell coming from, a pre-existing 
 cell, but the germinal matter is always the portion 
 in which it originates. 
 
 There is not generally a symmetrical division of 
 the nucleus into two, and these into four, as is so 
 often described, and as is often seen in the vegetable 
 cell, but there is rather a budding, and subsequent 
 dropping off of the portions of germinal matter 
 
THE CELL DOCTRINE. 91 
 
 "which is to produce the new cell, and which almost 
 alwaj's assumes the spherical form when allowed to 
 float freely. (See Figure 10 of frontispiece.) The 
 formed material is never active, according to Beale, 
 but entirely passive in the process of cell multiplica- 
 tion. 
 
 Nutrition of Cells. — So, too, in the nutrition of the 
 cell, the germinal matter is the sole active agent. 
 The formed material may act as a filter to the nu- 
 trient matter, but is quite passive. The pabulum, 
 which is coursing through the bloodvessels, becomes 
 converted into germinal matter, which in turn be- 
 comes formed material, aud so long as this is kept 
 up, the cell continues to grow. The course taken by 
 the pabulum, and the order of conversion, is shown 
 by the arrows, in Figure 17, of frontispiece, and will 
 be readily understood by reference to the explanation. 
 Occasionally, and especially in disease, the formed 
 material may become the pabulum for rapidly mul- 
 tiplying cells, and thus be consumed. 
 
 Intercellular substance has already been spoken of 
 as formed material. We have it most strikingly 
 present in the white fibrous tissue, or tissue of ten- 
 dons, and in hyaline cartilage. If the former be 
 stained by carmine, and examined in thin section 
 under the microscope, it will be found composed of 
 beautiful' bands of gently waving fibrous tissue, or 
 tissue exhibiting a fibrous appearance, at varying in- 
 tervals in which are noted nuclear masses of germinal 
 matter, which have assumed the tint of carmine. Or, 
 if dilute acetic acid be added to the specimen, the 
 fibrous appearance will at once become homogeneous, 
 
92 THE CELL DOCTRINE. 
 
 while the nuclei will be rendered distinct, and clearly 
 visible. In j'oung tendon (frontispiece, Fig. 11), the 
 masses of germinal matter will be found very abun- 
 dant, and the intercellular fibrous substance in smaller 
 quantity than in old tendon where the masses of ger- 
 minal matter occur only at long intervals. These 
 masses of germinal matter, or connective tissue cor- 
 puscles, it will be recollected, are considered by Vir- 
 chow as perfect cells, presenting cell-wall, cell con- 
 tents, and nucleus, and the fibrous intercellular sub- 
 stance as a subsequent modification of a homogene- 
 ous matrix, deposited between the cells by the blood- 
 vessels. These connective tissue corpuscles are re- 
 garded by Beale as simple masses of germinal matter, 
 the conversion of which into formed material pro- 
 duces the fibrous intercellular substance, as seen in 
 Fig. 11, frontispiece, and between which and the 
 intercellular substance immediately adjoining, there 
 is no line of separation, constituting a cell-wall. 
 
 As the tendon grows older, the masses of germinal 
 matter become less abundant, because a larger num- 
 ber have been totally converted into formed material ; 
 and the bands of indestructible material which some- 
 times join them, and which are considered by Virchow 
 as a part of his canalicular system, are, according to 
 Beale, nothing but im'perfedly converted formed material, 
 or rather germinal matter, which has not been con- 
 verted. While the twisted and curling cord-like 
 fibres of the so-called yellow elastic tissue, also con- 
 sidered by Virchow as a part of his canalicular sys- 
 tem, are thought by Beale to be composed in part of 
 true yellow elastic tissue, such as is found in the 
 
THE CELL DOCTRINE. 93 
 
 ligamentum nuchse, and likewise formed from nuclei 
 (frontispiece, Fig. 14), but in part also of the remains 
 of nerves and vessels, which were active at an earlier 
 period of life* 
 
 So, also, with hyaline cartilage. According to Beale, 
 the intercellular substance of cartilage results from 
 the cojiversion of the so-called cartilage-corpuscles or 
 cells into formed material, and here also the germinal 
 matter is directly continuous with the matrix, no 
 proper cell-wall intervening. 
 
 Cartilage is not to be considered as a distinct class 
 of tissue from epithelium, nor can the latter, in all 
 cases, be distinguished from cartilage by the exist- 
 ence of separate cells, since in many forms of epi- 
 thelium, at an e&v\y period of existence, the formed 
 material corresponding to the masses of germinal 
 matter is continuous throughout, and presents no 
 indication of division into cells.f A " cell," or "ele- 
 mentary part," then, of fully formed tendon or carti- 
 lage, would consist of a portion of germinal matter, 
 with a proportion of formed material about it, ex- 
 tending to a line midwa}' between that mass of ger- 
 minal matter and the masses immediately adjacent, 
 of which the cartilage or tendon is composed ; and 
 such a line would correspond to the outer part of 
 the surface of an epithelial cell.:}: In very young car- 
 tilages, as in very young epithelium, the cells consist 
 
 * Beale, On the Structure and Growth of the Tissues, and on 
 Life. London, 1865, pp. 95, 96, and 101. 
 
 f Beale, Protoplasm ; or. Life, Force, and Matter. London, 
 1870, p. 51. 
 
 % Beale, Protoplasm, pp. 51-2. 
 
94 THE CELL DOCTRINE. 
 
 of germinal matter only, with a small quantity of 
 soft formed material intervening ; and to understand 
 the true relation of the cells to the intercellular sub- 
 stance, the tissue should be studied at different pe- 
 riods of its growth. 
 
 So, too, a " cell " or elementary part of muscle or 
 nerve, would consist of a mass of germinal matter 
 (the eo-called nucleus), with a portion of muscular or 
 nervous tissue corresponding with it, and with which 
 it is uninterruptedly continuous. 
 
 In the formation of the contractile tissue or muscle, 
 the germinal matter seems to move onward, under- 
 going conversion at its posterior part, into the mus- 
 cular tissue, while it maintains itself by absorbing 
 and converting pabulum. This will be understood by 
 reference to Fig. 18, of frontispiece. The fibres of 
 yellow elastic tissue are formed in precisely the same 
 manner. (See frontispiece. Fig. 14.) Nerve fibres, 
 which in their completed state consist almost wholly 
 of formed material, are similarly produced. In the 
 youn^ state, the fibre is composed of masses of germi- 
 nal matter, linearly arranged, and in close proximity. 
 As the conversion takes place and the fibre is pro- 
 duced, these become more widely separated, and the 
 tissue resulting from such conversion is nerve (fron- 
 tispiece, Fig. 15). 
 
 The " Cell " or " Elementary Part " in Disease. 
 
 Here, as in normal nutrition, the germinal matter 
 is alone active. It is impossible to state precisely 
 every instance, but it is probable that in the majority 
 
THE CELL DOCTRINE. 95 
 
 of cases of disease, the morbid state consists essen- 
 tially in- a modification of the healthy nutrition of 
 the cell, that is, the cell is made to grow more or 
 less rapidly, or is perverted in its mode of growth, 
 though it is likely that within certain limits, the 
 conditions under which cells ordinarily live may be 
 modified without deviation from health. But in in- 
 flammat'ory processes attended by local products, as 
 pus or lymph, and in the production of tubercle and 
 cancer we see the results of excessive multiplication 
 and perversion of germinal matter consequent upon 
 the appropriation of an excess of nutrient pabulum. 
 In other instances, as cirrhosis, where there is shrink- 
 ing, and hardening, and wasting, we see the effects 
 of a diminished supply of pabulum, either through 
 a diminution in the quantity supplied, or an imper- 
 meability in the septum through which it is com- 
 pelled to pass. 
 
 An increased supply of pabulum may be admitted 
 to germinal matter, either in consequence of the 
 removal of barriers through which it is ordinarily 
 compelled to pass, or in consequence of the nature 
 of the fluids by which it is bathed. A simple illus- 
 tration is seen in suppuration in epithelium, or the 
 germinal matter of any tissue ; for, according to 
 Beale, suppuration and morbid processes generally, 
 are not restricted to any one kind of germinal 
 matter, as the connective tissue corpuscle, but may 
 occur in all germinal matter to which the conditions 
 are supplied. Using epithelium by way of illustra-tion-, 
 as the result of the increased supply of pabulum, the 
 germinal matter first grows, as seen in the frontispiece, 
 
96 THE CELL DOCTRINE. 
 
 Mgs. 7 and 8, then in the luxuriance of its growth, 
 even at the expense of the formed matter, sends out 
 buds or processes, which soon drop off and become 
 separate pus-corpuscles. (Figs. 9 and 10.) These 
 are produced so rapidly that there is not time for 
 formed material to form upon their surface in any 
 quantity, and they have not time, therefore, to pass 
 on into epithelium. Hence pus-corpuscles are almost 
 pure germinal matter. So soon as the process ceases, 
 in consequence of the supply of pabulum being di- 
 minished, the germinal matter multiplies less rapidly ; 
 opportunity is permitted for the production of formed 
 material on its periphery, and the cell now passes 
 through the different grades of epithelium, as de- 
 scribed on pages 88, 89, and 90. The pus-corpuscles 
 are analogous to the deepest layers of epithelial cells 
 there referred to, which deep cells are in fact the 
 " mucus-corpuscles," so-called, well known to be mor- 
 phologically identical with pus-corpuscles ; the for- 
 mer being simply the young epithelial cell on its way 
 to become perfect epithelium, while the latter is the 
 same also, though never allowed to pass into the 
 perfectly formed state. 
 
 Again, in pneumonia, and here we note where the 
 paths of Virchow and Beale separate more widely, the 
 so-called " exudation," or product which tills up the 
 vesicular portion of the lung, is regarded by Beale as 
 the result of a proliferation of minute "particles of 
 germinal matter (very much smaller than white blood- 
 corpuscles), which have passed out through the capil- 
 lary walls with the liquor sanguinis. 
 
 In all inflammatory processes and fevers, this is 
 
THE CELL DOCTRINE. 97 
 
 believed by Dr. Beale to take place to a greater or 
 less extent, the little masses of germinal matter or 
 nuclei in the capillary walls also taking part, often 
 increasing in size to such degree that they materi- 
 ally obstruct the passage of the blood, and by drop- 
 ping oft" portions give rise to bodies floating in the 
 blood precisely similar to white blood-corpuscles, or 
 pus-corpuscles ; indeed, Dr. Beale considers that this 
 may be one of the sources of origin of the white 
 blood-corpuscle.* 
 
 So, also, tubercle is believed by Dr. Beale to result 
 either from the multiplication of masses of germinal 
 matter which have passed through the capillary 
 walls from the blood, or from the masses of germinal 
 matter usually termed nuclei, in connection with 
 the capillary walls. He says, in illustration : " In a 
 case of tubercle, which was very rapidly developed 
 upon the surface of the pia mater, in a man of tuber- 
 cular constitution,. I proved most distinctly that the 
 tubercles were connected with the vascular walls, 
 and that if the nuclei had not given origin to them, 
 they were certainly implicated. My own opinion is, 
 that these nuclei gave origin to the tubercle-cor- 
 puscles, in consequence of receiving from the blood 
 peculiar nutrient matter. In the lung I have seen 
 appearances which point to a similar conclusion."t 
 Would not these views arise from appearances pre- 
 
 * Beale, Microscope in Clinical Medicine, third ed. London, 
 1867, p. 166. 
 f Microscope in Clinical Medicine, third ed., 1867, p. 205. 
 
 9 
 
98 THE CELL DOCTRINE. 
 
 cisely analogous to those represented as giving sup- 
 port to the view, that tubercle originates in the 
 perivascular sheaths of bloodvessels ? The views of 
 Beale, H. Charlton Bastian * and Cornil,t would 
 then constitute simply different modes of expression 
 of the same truths. 
 
 KOBiN,:]: 1867. 
 
 Eobin, who may be considered the mouthpiece of 
 the French school of histologists, reduces the human 
 body to elementary parts, usually microscopic, which 
 he calls anatomical elements. The forms he makes 
 threefold,— ^^fo'fis, tubes, and cells. 
 
 The fibres are generally of considerable length, 
 sometimes extending from the lower part of the 
 spinal cord to the extremity of the foot. Their di- 
 ameter is, however, small, often not exceeding .001 
 millimeter, or .00003987 of an inch. 
 
 The tubes offer as objects of study the walls and 
 the cavity. 
 
 * Bastian, H. 0., Tubero. Meningitis, Edinb. Med Jour., 1867, 
 p. 875. 
 
 f Cornil, Tubercle in Connection with the Vessels, Arcbiv. de 
 Phys. Norm, et Path., Jan. et Fev., 1868. 
 
 J Our information with regard to M. Eobin's views, is derived 
 from an admirable exposition of them published in vol. iv, 1867, 
 of the New York Medical Journal, by Dr. "William T. Lusk, who 
 there states that he has them mainly from a course of familiar 
 and private instruction, furnished to him by M. C. H. Georges 
 Pouchet, assistant to M. Robin, Lecturer upon Anatomy and His- 
 tology to the Ecolo Pratique, author of " Un Precis d'Histologie,'' 
 etc., and son of the eminent physiologist. Prof. F. A. Pouchet ; so 
 that they may be said to be the views also of the elder Pouchet. 
 
THE CELL DOCTRINE. 99 
 
 The cells of vegetables have a M'all, a cavitj', and 
 contents (air, oil, etc.). The cells oi animals, on the 
 contrary, are, as a rule, homogeneous. Animal cells 
 containing a cavity are only found exceptionally. 
 The substance of cells is ordinarily granular. Most 
 cells contain an ovoid nucleus more granular than 
 the substance itself. 
 
 In all cells the nuclei afford different chemical 
 reactions from those of the substance of the element. 
 Each cell is an independent organism, passing through 
 various stages of development, from birth to death. 
 
 The birth (origin) of the elements takes place by 
 1st, segmentation; 2d, genesis; 3d, epigenesis ; 4th, 
 germination. 
 
 1st. Segmentation. — The human ovum is a small 
 hollow sphere, containing in its interior the vitellus 
 or yolk, which consists of granular matter in a hya- 
 line substance. At the end of a certain time par- 
 ticles of the granular matter approximate, unite, and 
 form a nucleus in the vitellus. Next, the nucleus 
 elongates, takes an hour-glass form (biscuit), then 
 divides. The division of the yolk occurs simulta- 
 neously. In the same way, the division takes place 
 into 4, 8, 16, and more parts. These divisions of the 
 vitellus have received the name vitelline globules. 
 Their mode of formation is called segmentation. 
 
 2d. Genesis. — "When the vitelline globes have be- 
 come very small by successive segmentation (diame- 
 ter .008 millimeter, .00031396 of an inch), these little 
 bodies take the name of embryonic cells. 
 
 According to M. Eobin, these cells dissolve. From 
 the fusion results a blastema, in the midst of which 
 
100 THE CELL DOCTRINE. 
 
 nuclei make their appearance. This is known as 
 genesis. It is the second and most frequent mode of 
 the formation of anatomical elements. It is char- 
 acterized by. the appearance of an anatomical ele- 
 ment in 'a fluid termed blastema, in which the 
 element did not previously exist. 
 
 3d. Epige.nesis. — When the embryonic cells dis- 
 solve, the embryo -plastic nuclei are produced by 
 genesis in the blastema which results from their 
 fusion. Then little cone-like prolongations of trans- 
 parent matter are observed at the extremities of the 
 nuclei, giving rise to the fusiform bodies, which are 
 the connective tissue corpuscles. This mode of forma- 
 tion by growth upon another element is known as 
 epigenesis, and is the mode in which connective tissue 
 is developed. The prolongations of these fusiform 
 bodies constitute the non-elastic fibres or white 
 fibrous tissue element of connective tissue. Some- 
 times the substance deposited by epigenesis upon the 
 nucleus has several prolongations, forming a stellate 
 cell or connective tissue corpuscle. These fusiform 
 and stellate cells are likewise known as emhrgo-jylastio 
 ov fibro -plastic bodies, and this latter term is a most 
 common one in French histology. 
 
 The elastic fibres of connective tissue are likewise 
 formed by epigenesis, but upon special nuclei, and 
 the prolongations are insoluble in acetic acid. 
 
 There is an early period of foetal life, previous to 
 the formation of connective tissue, in which we find 
 only embryo-plastic nuclei and fusiform bodies in 
 amorphous matter. This is called embryo-plastic 
 tissue. Growth at this epoch is most rapid, the 
 
THE CELL DOCTRINE. . 101 
 
 fcEtus reaching in a short space of time the dimen- 
 sion of .030 millimeter (.0118 of an inch). 
 
 4th. Germination. — This is very frequent in vege- 
 tables, but in animals only one exam-pie is known, 
 viz., at a period previous to the fecundation of the 
 ovum. Before segmentation takes place the vitellus 
 is observed to retract. The hyaline substance pushes 
 out a prolongation, which becomes round, separates, 
 and constitutes, an independent anatomical element 
 exterior to the vitellus, and bearing no part in the 
 future development of the ovum. 
 
 The following account of certain special elements 
 illustrates and further explains the views of M. 
 Robin. Red blood-globules (hematics), dianieter, .007 
 millimeter (^-'n^ of an inch); thickness .002 milli- 
 meter (t2^52 of an inch). Blood-globules are elastic, 
 — a property enabling them to elongate, and pass 
 through capillaries which have a calibre less than 
 the diameter of the blood-globule. They are homo- 
 geneous throughout — i. e., have no cell-wall. Blood- 
 globules are formed by genesi^ in tHe blood ■plasma. In 
 the foetus they make their appearance before the 
 white blood-globules (leucocytes). In man there are 
 two kinds of red blood-globules, viz. : first, embry- 
 onic ; second, normal. The embryonic blood-globules 
 are double the size of the normal ones. They have 
 a slightly granular nucleus, situated nearly in the 
 centre, which is insoluble in acetic acid. The nor- 
 mal blood-globules are not a transformation of the 
 embryonic. They appear by genesis in the midst of 
 the blastema of the blood. After the fourth month, 
 the embryonic globules cease to form, and as the 
 
102 THE CELL DOCTRINE. 
 
 mass of the blood increases, the proportionate num- 
 ber diminishes with great rapidity. 
 
 Leucocytes, or white blood-globules, are found in 
 many tissues, in the blood, on the surface of mucous 
 membranes ; in a word.they are the pus-corpuscles. In 
 form, they are round, with pale, well-defined bor- 
 ders, and contain extremely fine gray granules. They 
 possess a very thin envelope, and a granular cell con- 
 tents. The normal diameter is .008 millimeter 
 (?T»']nr ^^ ^'^ inch). On the addition of water, the 
 leucocytes swell, the granular particles are agitated 
 by a peculiar movement (first observed by Brown), 
 and finally, a considerable number of these particles 
 unite, so as to form, two or three little masses, that have 
 been mistaken for nuclei. Upon the addition of acetic 
 acid the same reaction follows, but with greater 
 rapidity. 
 
 The mode of production may be followed, step by 
 step, upon the surface of wounds, especially little 
 ones. At first a hyaline liquid appears. At the end 
 of a couple of hours, this liquid becomes finely gran- 
 ular, and then all at once, in the midst of the granu- 
 lations, we perceive small granular bodies analogous 
 to leucocytes, offering the same chemical reactions, 
 but measuring only .003 millimeter (.000118 of an 
 inch) in diameter. They are, in fact, leucocytes of 
 young growth. When leucocytes are retained in the 
 ecbnomy, as in shut sacs, they increase in size, and 
 reach a diameter of .012 millimeter (j^'j^ of an inch). 
 Then they fill with fat-granules, and are known as 
 corpuscles of inflammation (exudation corpuscles, com- 
 pound granule-cells). Finally the substance and in- 
 
THE CELL DOCTRINE. 103 
 
 vesting membrane of the leucocytes disappear, the 
 granules dissolve and are reabsorbed. 
 
 Capillaries.— The finest capillaries are anatomical 
 elements of tubular form, with transparent resistant 
 walls which measure .001 mm. (.00003937 of an inch) 
 in diameter. These walls contain granular ovoid 
 nuclei, which project, sometimes exteriorly, some- 
 times upon the inner surface of the tubes. These 
 nuclei measure .006 mm. (.00028022 of an inch) in the 
 transverse, and .008 mm. (.00031596 of an inch) in 
 the long diameter. Their long axis is parallel to 
 that of the vessel. The finest capillaries have a 
 diameter of .007 mm. (.0003756 of an inch), leaving 
 a calibre (after deducting the walls) of .005 mm. 
 (.00019685 of an inch), or .002 mm. (.00007874 of an 
 inch) less than the average diameter of the blood- 
 globules Avhich traverse them. 
 
 They are formed as follows : 1st. In new tissues, 
 hollow projections push out from contiguous capil- 
 laries, which meet and unite together. 2d. A solid 
 filament forms, in which nuclei make their appear- 
 ance. Subsequently, the filament becomes hollow, 
 and its nuclei remain the nuclei of the capillary. 
 
 A single perusal of these views as thus illustrated, 
 will convince the reader that spontaneous formation is 
 the prevailing mode of origin of the elements of 
 tissues, according to the French school. Such pe- 
 rusal cannot fail to convince the reader also of the 
 accuracy of description of the fully formed elements 
 described by Robin. 
 
104 THE CELL DOCTRINE. 
 
 PROF, HUXLEY,* 1869. 
 
 There is one kind of matter which is common to 
 all living beings, and that matter is " protoplasm" 
 the scientific name for " the physical basis of life." 
 In illustration from vegetable life, each stinging 
 needle or hair of the common nettle consists of a 
 very delicate outer case of wood, closely applied to 
 the inner surface of which is a layer of semifluid mat- 
 ter, full of innumerable granules of extreme minute- 
 ness. This semifluid lining is protoplasm, which thus 
 constitutes a kind of bag, full of a limpid fluid, and . 
 roughly corresponding in form with the interior of 
 the hair which it fills. When viewed with a suffi- 
 ciently high magnifying power, the protoplasmic 
 layer of the nettle hair is seen to be in a condition of 
 unceasing activity. Local contractions of the whole 
 thickness of its substance pass slowly and gradually 
 from point to point, and give rise to the appearance 
 of progressive waves, just as the bending of successive 
 stalks of wheat by a breeze produces the apparent 
 billows in a wheat-field. 
 
 But in addition to these movements, and inde- 
 pendently of them, the granules are driven, in rela- 
 tively rapid'streams, through channels in the proto- 
 plasm which seem to have a considerable amount of 
 persistence. The currents in adjacent parts com- 
 monly take similar directions, coursing in a general 
 stream up one side of the hair and down the other, 
 
 * Protoplasm j or, The Physical Basis of Life. A Lecture by 
 Prof. Huxley, delivered in Edinburgh, November 18th, 1868. 
 
THE CKLL DOCTRINE. 105 
 
 though partial ctirrents also exist which take differ- 
 ent routes ; so that sometimes trains of granules 
 may be seen coursing swiftly in opposite directions, 
 within a twenty-thousandth of an inch of each other; 
 and occasionally opposite streams come in direct col- 
 lision, and after a longer or shorter struggle one pre- 
 dominates. The cause of these currents seems to lie 
 in contractions of the protoplasm which bounds the 
 channels in which they flow, but which are so minute 
 that the best microscopes show only their effects and 
 not themselves. 
 
 Among the lower plants it is the rule rather than 
 the exception, that contractility should be still more 
 openly manifested at some periods of their existence. 
 The protoplasm of Algas and Fungi becomes,'' under 
 many circumstances, partially or completely freed 
 from its woody case, and exhibits movements of its 
 whole mass, or is propelled by the contractility of 
 one or more vibratile cilia. 
 
 In illustration of animal protoplasm. Prof. Huxley 
 adduces the colorless corpuscles of the blood, which, 
 under the microscope, at the temperature of the body, 
 exhibit a marvellous activit}"^, changing their forms 
 with great rapidity, drawing in and thrusting out 
 prolongations of their substance, and creeping about 
 as if they were independent organisms. " The sub- 
 stance which is thus active is a mass of protoplasm, 
 and its activity differs in detail rather than in prin- 
 ciple from that of the protoplasm of the nettle. Under 
 sundry circumstances the corpuscle dies, and becomes 
 distended into a round mass, in the midst of which 
 is seen a smaller spherical body, which existed, but 
 
106 THE CELL DOCTRINE. 
 
 was more or less hidden, in the living corpuscle, and 
 is called its nucleus. Corpuscles of essentially similar 
 structure are to be found in the skin, in the lining 
 of the mouth, and scattered through the whole frame- 
 work of the body. Nay, more, in the earliest condi- 
 tion of the human organism, in that state in which 
 it has just become distinguishable from the egg in 
 which it arises, it is nothing but an aggregation of 
 such corpuscles, and every organ of the body was, 
 once, no more than such an aggregation. Thus a 
 nucleated mass of protoplasm turns out to be what may 
 be termed the structural unit of the human body. As a 
 matter of fact, the body, in its earliest state, is a 
 mere multiple of such units ; and, in its perfect con- 
 dition, it is a multiple of such units, variously modi- 
 fied." The formula which expresses the essential 
 structural character of the highest animal, very 
 nearly covers all the rest, as the statement of its 
 powers and faculties covered that of all others. 
 "Beast and fowl, reptile and fish, mollusk, worm, 
 and polype, are all composed of structural units of 
 the same character, namely, masses of protoplasm 
 with a nucleus. There are sundry very low animals, 
 each of which, structurally, is a mere colorless blood- 
 corpuscle, leading an independent life. But, at the 
 very bottom of the animal scale, even this simplicity 
 becomes simplified, and all the phenomena of life are 
 manifested by a particle of protoplasm without a nucleus. 
 " What has been said of the animal world is no less 
 ti'ue of plants. Imbedded in the protoplasm at the 
 broad, or attached end of the nettle hair, there lies 
 a spheroidal nucleus. Careful examination further 
 
THE CELL DOCTRINE. 107 
 
 proves that the whole suhstance of the nettle is made 
 up of a repetition of such masses of nucleated proto- 
 plasm, each contained in a wooden case, which is 
 modified in form, sometimes into a woody fibre, 
 sometimes into a duct or spiral vessel, sometimes 
 into a pollen grain, or an ovule. Traced back to its 
 earliest state, the nettle arises as the man does, in a 
 particle of nucleated protoplasm. And in the lowest 
 plants, as in the lowest animals, a single mass of such 
 protoplasm may constitute the whole plant, or the 
 protoplasm may exist without a nucleus. Under 
 these circumstances it may well be asked, how is one 
 mass of non-nucleated protoplasm to be distinguished 
 from another ? why call one ' plant,' and the other 
 ' animal ?' The only reply is that, so far as form is 
 concerned, plants and animals are not separable, and 
 that, in many cases, it is a mere matter of conven- 
 tion whether we call a given organism an animal or 
 a plant." 
 
 The researches of the chemist have also shown a 
 like uniformity of chemical composition in " proto- 
 plasm " or living matter, proving that whatever its 
 source, it contains carbon, hydrogen, oxygen, and 
 nitrogen, producing in their combination a complex 
 substance, which in our ignorance of its more exact 
 nature, we call proteinaceous or albuminoid matter. 
 
 Further, the matter of life is composed of ordi- 
 nary matter, and again resolved into ordinary matter 
 when its work is done. Waste is constantly going 
 on, which must be supplied by food, which is con- 
 verted into protoplasm. A solution of smelling salts 
 in water, with an infinitesimal proportion of some 
 
108 THE CELL DOCTRINE. 
 
 other saline matters, contains all the elementary 
 bodies which enter into protoplasm, yet an animal 
 cannot make protoplasm out of these. And this is 
 characteristic. It must take it ready made from 
 some other animal or some plant, the animal's highest 
 feat of constructive chemistry being to convert dead 
 protoplasm into the living matter of life, which is 
 appropriate to itself. Therefore, in seeking for the 
 origin of protoplasm, we must eventually turn to the 
 vegetable world. The plant, however, takes carbonic 
 acid, water, and ammonia,' and converts it to the 
 same stage of living protoplasm with itself, though 
 some of the fungi need higher compounds to start 
 with ; and no plant can live on the uncompounded 
 elements of protoplasm, and the absence of anj' one 
 of the elements renders the plant unable to manufac- 
 ture protoplasm. These elements, carbon, hydrogen, 
 oxygen, and nitrogen, are related to the protoplasm 
 of the plant as the protoplasm of the plant to the 
 animal. 
 
 Thus far it is plain that the views of Prof. Huxley 
 accord with those of many eminent histologists and 
 physiologists, the result of whose observations have 
 been embodied in these pages, and his descriptions 
 will be accepted as undoubtedly accurate. More 
 widely, in common with the school of so-called 
 " physicists," of which he is one, does he differ in 
 his views as to the phenomena exhibited by protoplasm. 
 
 According to Huxley, protoplasm once produced, all 
 the phenomena exhibited by it are simply its properties, 
 just as the phenomena exhibited by water in its various 
 states are properties. They do not take place through 
 
THE CBLL DOCTEINB. 109 
 
 the guidance of any principle called " vitality," any 
 more than the phenomena of water take place by 
 virtue of " aquosity." Prof. Huxley can discover no 
 halting-place between the admission that protoplasm 
 of one animal or vegetable is essentially identical 
 with and readily converted into another, and the 
 further concession that all vital action may, with 
 equal propriety, be said to be the result of the molecu- 
 lar forces of the protoplasm which displays it. The 
 thoughts to which we give utterance are the expression of 
 molecular changes in protoplasm. These are admit- 
 -tedly so-called materialistic terms. Yet Prof. Huxley 
 says: "Ilfevertheless, two things are certain : the one, 
 that.1 hold the statement (above) to be substantially 
 correct ; the other, that I, individually, am no material- 
 ist, but on the contrary believe materialism to involve 
 grave philosophical errors." Such union of materialis- 
 tic terminology with the repudiation of materialistic 
 philosophy, he believes to be " not only consistent 
 with, but necessitated by sound logic." This he pro- 
 ceeds to show in this manner : If it be supposed that 
 knowledge is absolute, that we know more of cause 
 and eftect than a certain definite order of succession 
 of facts, and that we have a knowledge of the ne- 
 cessity of that succession, then there is no escape 
 from utter materialism and necessarianism. But it 
 is impossible to prove that anything whatever may 
 not be the effect of a material and necessary cause, 
 and no act is really spontaneous, since a really spon- 
 taneous act is one which has no cause. Yet any one 
 familiar with the history of science will admit that 
 its object has always meant, and means the exten- . 
 
 10 
 
110 THE CELL DOCTRINE. 
 
 sion of the province of matter and causation, and the 
 concomitant gradual banishment from all regions of 
 human thought, of what we call spirit and sponta- 
 neity, — that is, the object of all science has been and 
 is to find out the causes of all phenomena ; and there 
 is no difference Ijetween the conception of life as the 
 product of a certain disposition of material molecules, 
 and the old notion of an Archseus governing and di- 
 recting blind matter within each living body, except 
 that here, as elsewhere, matter and law have devoured 
 spirit and spontaneity. And moreover, the physiology 
 of the future will gradually so extend the realm of 
 matter and law, until it is coextensive with knowl- 
 edge, with feeling, and with action. It is this prog- 
 ress of knowledge, according to Prof. Huxley, which 
 so many of the best minds conceive to be the progress 
 of materialism., which they watch with such fear and 
 powerless anger as a savage feels^ when, during an 
 eclipse, the great shadow creeps over the face of the 
 sun. We know nothing of this terrible " matter," 
 except as the name for the unknown and hypotheti- 
 cal cause of states of our own consciousness, and as 
 little of that " spirit," except that it is also a name 
 for an unknown and hypothetical cause of states of 
 consciousness, that is, matter and spirit are both 
 names for the inaaginary substrata of groups of natu- 
 ral phenomena. Dire necessity and " iron " law are 
 gratuitously invented bugbears. If there bean " iron" 
 law, it is that of gravitation, and if there be a physi- 
 cal necessity, it is that a stone unsupported will fall 
 to the ground. We know nothing more of this latter 
 phenomenon, except that stones always have fallen 
 
THE CELL DOCTRINE. Ill 
 
 to the ground under these conditions, and that they 
 will continue to fall to the ground thus unsupported. 
 
 It is simply convenient to indicate that all the con- 
 ditions of belief in this case have been fulfilled, by 
 calling the statement that unsupported stones will 
 fall to the earth a " law of nature." But when for 
 will we exchange 7nust, we introduce an idea of neces- 
 sity which does not lie in the observed facts, and is 
 not warranted by anything that is discovered else- 
 where. And with regard to which Prof. Huxley 
 says : " For ray part, I utterly repudiate and anathe- 
 matize the intruder. Fact I know, and Law I know ; 
 but what is this necessity, save an empty shadow of/ 
 my own mind's throwing? But, if it is certain that 
 we can have no knowledge of the nature of either 
 matter or spirit, and that the notion of necessity is 
 something illegitimately thrust into the perfectly 
 legitimate conception of law, the materialistic position 
 that there is nothing in the world but matter, force, and 
 necessity, is as utterly devoid of justification as the most 
 baseless of theological dogmas. 
 
 " The fundamental doctrine of materialism, like 
 those of spiritualism, and most other ' isms,' lie out- 
 side ' the limits of philosophical inquiry,' and David 
 Hume's great service to humanity is his irrefragable 
 demonstration of what these limits are. Hume 
 called himself a skeptic, and therefore others cannot 
 be blamed if they apply the same title to him ; but 
 that does not alter the fact that the name, with its 
 existing implications, does him gross injustice. If 
 a man asks me what the politics of the inhabitants 
 of the moon are, and I reply that I do not know ; 
 
112 THE CELL DOCTRINE. 
 
 that neither I nor any one else have any means of 
 knowing ; and that, under these circumstances, I de- 
 cline to trouble myself about the subject at all, I do 
 not think he has any right to call me a skeptic. On 
 the contrary, in replying thus, I conceive that I am 
 simply honest and truthful, and show a proper regard 
 for the economy of time. So Hume's strong and 
 subtle intellect takes up a great many problems 
 about which we are naturally curious, and shows us 
 that they are essentially questions of lunar politics, 
 in their essence incapable of being answered, and 
 therefore not worth the attention of men who have 
 work to do in the world." .... 
 
 " If we find that the ascertainment of the order of 
 nature is facilitated by using one terminology, or one 
 set of symbols, rather than another, it is our clear 
 duty to use the former, and no harm can accrue so 
 long as we bear in mind that we are dealing merely 
 with terms and symbols. In itself it is of little mo- 
 ment whether we express the phenomena of matter 
 .in terms of spirit, or the phenomena of spirit in 
 terms of matter ; matter may be regarded as a form 
 of thought, thought may be regarded as a property 
 of matter — each statement has a certain relative 
 truth. But with a view to the progress of science, 
 the materialistic terminology is in every way to be 
 preferred. For it connects thoAght with the other 
 phenomena of the universe, and suggests inquiry 
 into the nature of those physical conditions, or con- 
 comitants of thought, which are more or less acces- 
 sible to us, and a knowledge of which may, in future, 
 help us to exercise the same kind of control over the 
 
THE CELL DOCTRINE. 113 
 
 world of thought as we already possess in respect to 
 the material world ; whereas, the alternative, or 
 spiritualistic terminology is utterly barren, and leads 
 to nothing but obscurity and confusion of ideas. 
 Thus, there can be little doubt that the further 
 science advances, the more extensively and consist- 
 ently will all the phenomena of nature be represented 
 by materialistic formulae and symbols. But the man 
 of science, who, forgetting the limits of philosophical 
 inquiry, slides from these formulae and symbols into 
 what is commonly understood by materialism, seems 
 to me to place himself on a level with the mathema- 
 tician, who should mistake the z's and y's, with 
 which he works his problems, for real entities, and 
 with this further disadvantage, as compared with the 
 mathematician : that the blunders of the latter are of 
 no practical consequence, while the errors of sys- 
 tematic materialism may paralyze the energies and 
 destroj' the beauty of a life." 
 
 These are the views of the " physicists," so-called, 
 a school represented by Prof. Huxley, Prof. Owen, 
 Herbert Spencer, Mr. Grove, Prof. Tyndall, and 
 others. Prof. Owen, in the last pages of vol. iii of 
 llie Anatomy of the Vertebrates, declares himself the 
 champion of spontaneous generation, and he main- 
 tains, also, that the formation of living beings out of 
 inanimate matter by the conversion of physical and 
 chemical into vital modes of force, is a matter of 
 daily and hourly occurrence. Mr. Grove says that 
 " in a voltaic battery and its effects we have the 
 nearest approach man has made to an experimental 
 organism," and that in the human body we have 
 
 10* 
 
114 THE CELL DOCTRINE. 
 
 chemical action, electricity, magnetism, heat, light, 
 motion, and possibly other forces " contributing, in 
 the most complex manner, to sustain that result of 
 combined action we call life." 
 
 ADDISON, WALLER, COHNHEIM (1842, 1846, 1867). 
 
 At the annual meeting of the Provincial Medical 
 and Surgical Association of England, held at Exeter, 
 August 3d and 4th, 1842, William Addison read a 
 paper entitled "Experimental and Practical Re- 
 searches on the Structure and Eunction of Blood-cor- 
 puscles, on Inflammation, and on the Origin and Na- 
 ture of Tubercles in the Lungs." In the section " On 
 Pus-corpuscles," he says : " The colorless blood-cor- 
 puscles appear to form pus-corpuscles."- In the section 
 on " Inflammation," we find the following : " The cir- 
 culation in the web of a frog's foot was watched at 
 intervals for half an hour, and only a few lymph-glob- 
 ules were seen. A crystal of salt was applied, and 
 the examination continued : its first eftect was to 
 quicken the rate of the circulation ; this soon ceased, 
 and the blood became stationary, the vessels being 
 red and congested. In the capillaries contiguous to 
 the congested vessels, the blood was oscillating to and 
 fro ; a little further oft", the circulation was very quick. 
 In half an hour the number of lymph-globules had 
 increased considerably, and the circulation in the 
 congested vessels was resumed ; but the corpuscles 
 passing through them sometimes oscillated to and 
 fro, sometimes retrograded, and at others hurried or 
 darted through the vessels with the utmost velocity. 
 
THB CELL DOCTRINE. 115 
 
 The current of the red corpuscles in some of the 
 veins appeared to be confined to the centre of the 
 vessel, and not to touch the circumference, which was 
 occupied by a great ipany lymph-globules. On the 
 following morning the whole interior of the inflamed 
 vessels appeared to be lined with lymph-globules. 
 By gently altering the focus of the microscope they 
 were seen below the red current, and inany of them 
 appeared to lie exfernally to the boundary of the vessels." 
 
 Again, page 258:* " During some of these experi- 
 ments the islets of tissue between the capillaries be- 
 came distinctly cellular, and appeared as if over- 
 spread with irregular-shaped lymph-globules." 
 
 These various statements, while they permit the 
 inference that Addison first conceived that the col- 
 orless blood-corpuscle becomes the pus-corpuscle in 
 inflammation, do not allow us to infer that he actu- 
 ally observed its migration through the walls of 
 vessels. Indeed, he says, page 259 : " The phenomena 
 observed in the foregoing experiments corroborate 
 the views of those distinguished physiologists who 
 entertain the opinion that the capillary distribution 
 of the blood is situated in the channels of the tissue, 
 and not in vessels with a distinct membranous coat."t 
 
 In 1846 Waller:}: more correctly appreciated this 
 migration, but it was not until Cohnheim published 
 his famous paper on " Inflammation and Suppura- 
 
 * The Transactions of the Provincial Medical and Surgical 
 Association, vol. xi. London, 1843. 
 
 •f- MttUer's Physiology, vol. i, p. 229. 
 
 J London, Dublin, and Edinburgh Philosophical Magazine, 
 vol. xxix, pp. 271 and 398. 
 
116 THE CELL DOCTRINE. 
 
 tion,"* in 1867, that the observation attracted the 
 attention it deserved. Since then it has been con- 
 firmed again and again, and most conclusively lately 
 by Arnold, of Heidelberg. t 
 
 The theory which grew out of Cohnheim's obser- 
 vation was, that it is the colorless corpuscle of the blood, 
 rather than the connective tissue corpuscle, which is 
 the starting-point of all new formations, healthy and 
 morbid. It is the accumulation of these corpuscles 
 outside of the bloodvessels, in the interspaces of the 
 fibrillar connective tissue, which forms the beadlike 
 rows of cells figured by Virchow and others. It is these 
 which, accumulated in larger numbers, forms the pus 
 of an abscess. It is these which, perverted in the 
 direction of their development, produce the tissu'e of 
 tubercle, cancer, sarcoma, and other forms of morbid 
 growth. It is these, also, which become the medium 
 of repair of all injured or destroyed tissues which are 
 capable of regeneration, whatever their complexity 
 or simplicity. 
 
 That the colorless corpuscle plays a most important 
 role in the production of new formations, healthy 
 and morbid, few now deny ; but that it is the sole 
 morphological element, exclusive of the connective 
 tissue corpuscle, thus active, many will not admit. 
 Conspicuous among those who have combated this 
 exclusive view are Strieker and Norris,! whose ob- 
 
 * Ueber Entziindung und Eiterung, Virchow's Archiv, Bd. xl, 
 1867, p. 1. 
 
 f Ueber Diapedesis, Virchow's Archiv, vol. 58, 1873. 
 
 % Versuohe iiber Hornhaut Entziindung, Studien aus dem In- 
 stitute fiir Experimentelle Pathologle in Wien, aus dem Jahre 
 1869. 
 
THE CELL DOCTRINE. 117 
 
 servations and experiments in the production of 
 inflammation in tlie cornefe of frogs and rabbits have 
 attracted much attention. Their object was to show 
 that the connective tissue corpuscles (the corneal cor- 
 puscles here) shared in the formation of the products 
 of inflammation by their proliferation, and that the 
 colorless corpuscles themselves, after their migration 
 beyond the walls of the bloodvessels, also underwent 
 cell division, and thus contributed in a second man- 
 ner to the formation of pus. They argued, also, that 
 the enormous accumulations pf pus in large abscesses 
 could not be reasonably accounted for on the ground 
 that the only source of the pus-corpuscle is the wan- 
 dered-out colorless corpuscle. 
 
 These observations of Strieker and Norris are gen- 
 erally acknowledged as having settled the question 
 in favor of the view, that there are two elements of 
 organization, — the colorless corpuscle and the connec- 
 tive tissue corpuscle, either of which may also become 
 the starting-point of pathological new formations. 
 
 NEW VIEWS ON THE STUUOTUEE OF CELLS AND 
 
 NUCLEI.— 1877-78. 
 As early as 1867, C. Frommann* published a pam- 
 phlet on the "ISTormal and Pathological Anatomy of 
 the Spinal Cord," in which he states that the pres- 
 ence of fibrils in the nuclei and nucleoli of cells, first 
 observed in ganglion-cells, was demonstrated by him 
 also in the cells of connective tissue, cartilage, and 
 
 * Untersuchungen fiber die normale und pathologische Anato- 
 mie des Bfickenmarks, 2 Theil. Jena, 4. Mit 6 Taf. p. 17. For 
 abstract of, see Henle and Meissner's Berioht fiber die Forschritte 
 der Anatomie und Physiologie, in Jahre 1867, Leipzig, 1868. 
 
118 THE CELL DOCTRINE. 
 
 bone-cells, and in the epithelium of the mouth and 
 capillary vessels. He observed clear shining fibrils pro- 
 ceeding from the nucleolus joining themselves to others 
 proceeding from the nucleus and protoplasm. From 
 the nucleoli of connective tissue arise one, two, and, 
 more seldom, three fibrils. These sometimes dwindle 
 away in the nucleus itself; at others, after a straight 
 or curved course, leave the cell and lose themselves 
 in the neighborhood. Repeatedly was observed the 
 entrance of a nucleolus-fibre into a cell process, and 
 if two cells were united by a process from each, the 
 nucleolus-fibre was seen to pass from one cell to 
 another. So also fibres originating in the nucleus, 
 sometimes as many as six in number, could be fol- 
 lowed into the protoplasm, and more seldom beyond 
 the cell. Certain fibres appear to cease in the nu- 
 cleus by a free extremity, as though cut oft'. Others 
 have attached to them glistening granules, which in 
 fresh, as well as hardened preparations, are con- 
 tained in variable number in the nucleus. Frommann 
 believes that the granules of the nucleus and proto- 
 plasm are the nodal points of a very fine fibrous net- 
 work, from which fibrils go off" and leave the cell. 
 These are found in the cells of all the tissues named 
 above. In consequence of this complicated structure 
 of the nucleus, Frommann thinks it improbable that 
 it multiplies by division ; he believes in a free new 
 formation of the nucleus in the protoplasm, where, 
 alongside of nuclei of ordinary appearance, smaller 
 homogeneous ones make their appearance. 
 
 In ,1873,* Heitzmann asserted that the substance 
 
 * Untersuchungen iiber das Protoplasma, Sitzungsber., d. k. 
 Akad. d. Wiss. zu Wien, Bd. Ixvii und Ixviii, Abth. iii, 1873. 
 
THE CELL DOCTRINE. 119 
 
 of various cells, araoebse, blood-corpuscles, cartilage- 
 cells, bone-cells, epithelial cells, etc., contain net- 
 works of minute fibrils, into which pass fibrils radi- 
 ating from the interior of the nuclei of these cells. 
 
 In 1875, Frommann* again described, in accordance 
 with Heitzmann, a minute network of fibrils in the 
 nuclei of blood-corpuscles of Astacus fluviatilis, which 
 passed through the nuclear membrane into a similar 
 network in the substance of the blood-corpuscles. 
 
 Schwalbe,t in 1875, found the nucleoli in the nuclei 
 of ganglion-cells in the retina often possessed of mi- 
 nute filamentous prolongations, and the nuclear 
 membrane showing prominences on its inner surface, j 
 Schwalbe designates as " nucleolarsubstanz," the nu- 
 cleolus and filaments, nuclear membrane and its 
 prominences, to distinguish it from the rest of nu- 
 clear matter, which he calls " kernsaft " or " nuclear 
 juice." 
 
 KupfferjJ in 1875, maintained that the substance 
 of the lower cells of the frog, the odontoblasts, the 
 epithelial cells of the salivary gland of Periplaneta 
 orientalis, is composed of a hyaline (non-fluid) ground 
 
 See also a paper by Heitzmann on the same subject, in the New 
 Tork Medical Journal for 1877. For the historical facts from this 
 date in the development of these new views, 1 am indebted to the 
 very valuable paper of Dr. Klein in the Quarterly Journal of Mi- 
 croscopical Science for July, 1878. 
 
 * Frommann, Zur Lehre von der Struotur der Zellen, Jenaische 
 Zeitschrift f. Naturw., Bd. ix, 1875, p. 280. 
 
 f Bemerkungen iiber d. Kerne d. Ganglionzellen, Jenaische 
 Zeitschrift f. Naturw., Bd. x, 1875, p. 25. 
 
 J UeherDifferenzirung d. Protoplasmaan den Zellen thierescher 
 Gew., Schriften ,des Naturw. Vereins f. Schleswig-Holstein, Heft 
 ill; and Beitr. z. Anat. u. Physiol., Pcstgabe f. Carl Ludwig, 1875. 
 
120 THE CELL DOCTRINE. 
 
 substance, " Paraplasma," and of a granular fibrillar 
 contractile " Protoplasma," imbedded in the former. 
 The relation and distribution of the protoplasmic 
 fibrillar substance varies in cells of different kinds. 
 
 Strasj^burger * in 1876, observed that in developing 
 cells of Pliaseolus multiflorus^ a network of fibrils is 
 present radiating from the nucleolus, and permeating 
 the interior of the nucleus in connection with a simi- 
 lar network of the cell substance. 
 
 In 1876, Butschlif observed in the nuclei of colored 
 blood-corpuscles of the frog and newt, minute fibres 
 with granular thickenings, but no nucleolus as as- 
 serted by Ranvier. 
 
 Moyzel,:^ in 1875, found in the epithelium of the 
 cornea of the frog, rabbit, and cat, during regenera- 
 tion, large round nuclei, in which he observed filamen- 
 tous masses, either convoluted or radiating from a 
 central point. He regarded these forms as due to a 
 particular stage of division, as described by Biitschli 
 and Strasfeburger. 
 
 0. Hertwig,§ in 1876, also distinguished a " nuclear 
 substance," from a " nuclear juice," and Biitschli,|| in 
 the same year, a " nuclear matter " from a " nuclear 
 fluid." The "nuclear matter" of the latter com- 
 
 * TJeber Zellbildung und ZelUheilung, Jena, 1875. Abstract in 
 Quart. Jour. Mie. Sci., vol. xvi, 1876, p. 138. 
 
 t Studien iiber die ersten Entwickolungserscheinungen der 
 Eizelle, Abhandl. d. Senljenbergisohen Naturf. Gesellsch., Bd. x, 
 1876. 
 
 % TJeber eigenthumliolie Vorgange bei der Theilung der Kerne 
 in Epithelialzellen, Centralbl. f. Medic. Wissensch., No. 50, 1875. 
 
 J Beitrage zu einer einheitliohen Auffassung dor versehiedenen 
 Kornformen, Morphol. Jahrbuoh, 1876, Bd. 2, H. 1, 1876, p. 73. 
 
 II Loc. citat., vol. x. 
 
THE CELL DOCTRINE. 121 
 
 prises the nuclear membrane, the nucleolus, and a 
 fibrillar stroma, which latter, in some instances, ex- 
 tends in a radial manner from the nucleolus. 
 
 E. Van Beneden* saw a fine protoplasmic reticu- 
 lum in the large axial entoderm cell of Dicyema, 
 which (reticulum) exhibited slow spontaneous move- 
 ments. In the nucleus of the ripe ovum of Astero- 
 canihion rubens he also observed within the nuclear 
 membrane and beside the nucleolus a delicate net- 
 work of finely granular substance, which he calls 
 "nuclepplasma," including several " pseudo-nucleoli." 
 According to him the germinal vesicle of the ripe 
 ovum of the rabbit also contains a minute network. 
 
 Arudt,t in 1876, distinguished in the nucleus a 
 homogeneous ground substance and elementary glob- 
 ules ; the former possesses a vesicular structure, and 
 incloses in its meshes the latter. 
 
 W. FJemming,:]: in observations on the structure 
 of nuclei found in the membrane of the urinary blad- 
 der of Salamandra maculata, in 1876, saw a very deli- 
 cate and dense network of fibres uniformly pervading 
 the interior of the nucleus, and attached to the 
 nuclear membrane. This network, " Geriistformige 
 
 * La maturation de I'oeuf, la fecondation et les premi&res phases 
 du dfiveloppement embryonaire des Mammiftres. Bui. de I'Acad. 
 Koyale de Belgique, 2 Ser., t. 40, 1875; also Contributions I. Phis- 
 toire de la vfesieule germinative et du premier noyau embryonaire, 
 in the same journal, January, 1876. 
 
 ■j- tjber den Zellkern, Sitzungsb., d. Medicin. Vereins zu Greifs- 
 wald, Nov., 1876. 
 
 ^ Bcobachtungen iiber die Beschaffenheit des Zellkerns, Archiv 
 fiir Mikrosls. Anat., Bd. xiii, 1876, p. 693, and following. 
 
 11 
 
122 THE CELL DOCTRINE. 
 
 Structur," was seen by Flemraing in the nucleus of 
 all cellular elements of the bladder of Salamandra, 
 epithelial cells, connective tissue cells, migratory 
 cells, unstriped muscle-cells, nerve-cells, endothelial 
 cells, and blood-corpuscles. With regard to Flem- 
 ming's observations, Klein* says their clearness and 
 extent leave no doubt that the network in the nu- 
 cleus represents a definite and pre-existing structure. 
 This has been to a certain extent questioned by Lang- 
 hansf as regards the fresh cells of the human decidua 
 serotina, but, Klein again observes, "Memming's 
 assertions cannot be in the least shaken, considering 
 that he observed the above structure, not only after 
 the use of reagents, e. g., acetic acid, chromate of 
 potash, alcohol, chromic acid, with or without sub- 
 sequent staining in carmine or hsematoxylin, but also 
 in the absolutely uninjured bladder, i. e., while this 
 organ was being observed in the living curarized 
 animal." And, in a later note, Flemniing:|: states 
 that he observed the same network in the nuclei of 
 various cells, also in the living and perfectly unin- 
 jured larva of Salamandra. 
 
 Eberth§ noticed nuclei containing anastomosing 
 filaments in their interior in the epithelium of the 
 cornea and the endothelium of the membrana Des- 
 cemeti under normal conditions. He regards them 
 
 * Loc. citat. 
 
 \ Zur Lehre von Zusammensetz. des Kerns, Centralblatt f. 
 Medic. Wissenschaft, 1876, N. 50. 
 
 J Zur Kenntniss des Zellkerns, in Centralbl. f. Medic. Wiss., 
 1877, No. 20. 
 
 § Ueber Kern imd ZelUheilung, Virohow's Archiv, Bd. 67, 
 1876. 
 
THE CELL DOCTRINE. 123 
 
 as peculiar forms in the development and division of 
 nuclei. 
 
 Eimer* found in numerous nuclei that the gran- 
 ules of the " granular zone " surrounding his " hya- 
 loid " are due to protoplasmic filaments, which per- 
 meate the interior of the nucleus, and anastomose 
 with each other so as to form a network, which ex- 
 tends to the membrane of the nucleus, and also sends 
 radiating fibrils through the hyaloid into the nu- 
 cleus. The network of fibrils of the nucleus is, in 
 some instances, also in connection with fibrils and 
 networks of the same belonging to the cell substance 
 itself. 
 
 The most recent contribution on this subject is the 
 valuable paper by Dr. E. Klein, already' alluded to, 
 and published in the Quarterly Journal of Microscopical 
 Science, for July, 1878. In this paper Klein shows 
 by observationsf on the ordinary freshly killed newt 
 
 * Weitere Nachrichten uber den Bau des Zellkerns, etc., Archiv 
 f. Mikrostf. Anat., Bd. xiv, 1877, p. 94. Also, " JSotes and Mem- 
 oranda" of the April number of the Quart. Jour. Microso. Sci., ' 
 1878. 
 
 j- The following is the method pursued by Klein : The stomach 
 of a freshly killed newt is cut open and placed Into a 5 per cent, 
 solution of chromate of ammonia in a closed vessel, where it is kept 
 for about twenty-four hours. It is then washed in water for about 
 half an hour, and placed after this in a dilute solution of piero- 
 carmine, where it is left till it assumes a deep pinkish-yellow tint. 
 It is now washed in water, and microscopic specimens are pre- 
 pared in this manner. The mucous surface of the organ is scraped 
 with a small scalpel, iwhereby smaller or larger flakes may be easily 
 removed ; they are placed in a very tiny droplet of glycerin on a 
 glass slide ; by slight knocking with the rounded or flat top of any 
 thin rod or needle-holder these flakes are broken up into micro- 
 
124 THE CELL DOCTRINE. 
 
 {Triton eristatus), that the statements of Flemming 
 are correct, and presents in addition several observa- 
 tions he has made with reference to the cell-sub- 
 stance itself, and the relation of it to the intranuclear 
 network. 
 
 Dr. Klein examined gland-cells, surface epithelial 
 cells, endothelium, unstriped muscle-fibres, connec- 
 tive tissue corpuscles, and nerve-fibres. And every 
 where the nuclei showed an extremely beautiful net- 
 work of fibrils. This he designates as the intra- 
 nuclear network, which is imbedded in a homoge- 
 neous ground-substance. Tie network does not in 
 all instances extend up to the nuclear membrane, but 
 leaves a narrower or broader zone next to the mem- 
 brane unoccupied. But in all instances the network 
 is in connection with the limiting membrane by nu- 
 merous fibrils. The spaces formed by their anasto- 
 moses are not uniform, being sometimes larger in the 
 peripheral parts- than in the central, and sometimes 
 the reverse. All forms are found between a network 
 with fibrils as in a net, and a honeycomb of mem- 
 branous structure as in a sponge. In almost all in- 
 stances are observed a smaller or greater number of 
 
 scopic fragments, a drop of glycerin is placed on a covering-glass, 
 and this is inverted over the above specimen. 
 
 Examined under a moderately high power, say Hartnack's 7 or 
 8, or Zeiss's D or E, we recognize easily innumerable isolated cells 
 or groups of epithelial cells, and a great many isolated nuclei or 
 fragments of nuclei. If the scalpel has been drawn over the sur- 
 face of the mucous membrane with a little energy, the preparation 
 contains great numbers of gland-cells, isolated and in continuous 
 masses, and also other elements belonging to the tissue of the 
 mucosa. 
 
THE CELL DOCTRINE. 125 
 
 minute bright spots, which are shown by careful 
 focussing to be fibrils of the network seen in optical 
 transverse section or at the points of anastomosis. 
 In some nuclei, according to Klein, the more irregu- 
 larly shaped dots are due to a thickening of fibrils 
 from place to place, although Flamming attributes 
 them altogether to the former cause^ (transverse sec- 
 tions of fibrils). Whence it is clear, the more shrunk 
 the intranuclear uetwoz'k, or the more twisted and 
 convoluted the fibrils, the more does the nucleus 
 present the appearance of being granular. 
 
 The nucleolus receiv^e an entirely peculiar expla- 
 nation at the hands of Klein, in which he seems to be 
 sustained by the observations of Van Beneden, 0. ' 
 Hertwig, Flemming himself, Auerbach, Eimer, and 
 especially of Strasj^burger, Schwalbe, and Langhans. 
 With regard to it Klein first says with undoubted 
 truth : " I^fow, to every experienced student of his- 
 tology, it must have become apparent that if there 
 is one thing unsatisfactory, unreliable, puzzling, and 
 inconstant about the nucleus of vast numbers of 
 cells, it is this very nucleolus." Second, that after 
 a very prolonged examination he has arrived at the 
 conclusion that these large particles (nucleoli) are 
 due to one of two things : in some instances they are 
 distinctly thickenings of the network, in others they 
 appear to be merely due to the shrivelling up and 
 intimate fusion of a part of the network. The in- 
 constancy as regards size, shape, and number of the 
 so-called nucleoli seem to him to point very strongly 
 in the above_ direction. 
 
 The assertions which have been made as regards 
 11* 
 
126 THE CELL DOCTRINE. 
 
 spontaneous movements of nucleoli by Auerbaeh, 
 Brandt, Eimer, Kidd, and others, he regards as quite 
 compatible with the above view, for Van Beneden 
 has observed movements in the intranuclear network, 
 and it is quite possible that the above assertions 
 might refer to such movements. 
 
 With regard to the nuclear membrane already men- 
 tioned, Klein says that it is composed of an outer 
 thicker portion, which is the limiting membrane proper 
 and closely connected with it, an inner, more or less 
 incomplete layer, which is a peripheral condensation 
 of the intranuclear network, with which it is connected 
 by longer or shorter threads. The clear space some- 
 times observed between the membrane of the nucleus 
 and the intranuclear network is due to a retraction 
 of the latter from the former. 
 
 Klein has also demonstrated a network of fibrils 
 in the substance of cells outside of the nucleus, which 
 he designates as the intracellular network, in contra- 
 distinction to intranuclear, in the meshes of which 
 again is the interfibrillar or ground^substance, which 
 in the case of the columnar epithelial cells on mucus- 
 surfaces, known as goblet-cells, is mucus,* but finds 
 them also in the endothelium of the surface, in un- 
 striped muscle-fibres, connective tissue corpuscles, and 
 nerve-fibres. 
 
 Klein further traces a direct connection of the fibrils 
 
 * They are best seen on the slender goblet-cells of the stomach 
 of the newt, kept for twenty-four hours in MuUer's fluid, placed 
 then for half an hour in a mixture of two parts chromic acid (J 
 per cent.), and one part methylated alcohol, washed after this in 
 water, and stained with picro-carmine. 
 
THE CELL DOCTRINE. 127 
 
 of the intracellular with those of the intranuclear network, 
 and along with Eberth, Marchi, and Eimer, traces in 
 the epithelial cells of the foregut of the newt, the 
 cilia in direct continuation through the cell-cover with 
 the fibrils of the intracellular network. 
 
 The intracellular network is less conspicuous than 
 the intranuclear, but possesses the same general 
 characters. 
 
 The importance of this subject has seemed so great 
 that I have added at the end of the volume the essen- 
 tial portions of* the plate from the Quart. Jour, of 
 Micros. Sci., for July, 1878, which, with its descrip- 
 tion, will give a very accurate notion of these new 
 views as confirmed by Dr. Klein, than whom, of 
 modern observers, I consider none more reliable. 
 
 summary — present state of the cell doctrine — 
 author's views. 
 
 Minute analysis of the solids of the organism has 
 long been an object of the histologist and physiolo- 
 gist, which, resulting first in the partes similares of 
 Aristotle and Galen, has finally reached the so-called 
 " cell " or " elementary part " as the ultimate physi- 
 cal element of organization, out of which all tissues, 
 healthy or diseased, are formed. Our ideas as to the 
 exact physical constitution of this elementary part 
 have undergone considerable change since the first 
 announcement by Schleiden and Schwann, in 1838, of 
 its exact physiological position. The most impor- 
 tant modifications of the original conception of a cell 
 is that which removes altogether its vesicular char- 
 
128 THE CELL DOCTRINE, 
 
 acter. So that the term " cell " is really no longer a 
 correct one, since the object to which it is applied is, 
 in its youngest, most active state, at least, a solid 
 mass or "clump " of .living matter without the ves- 
 tige of a wall or envelope about it. The word has, 
 however, become so intimately associated with his- 
 tology that it is doubtful whether it will ever fall 
 into disuse, nor does it much matter, so long as cor- 
 rect notions of the elementary part are obtained. 
 This latter term, " elementary part," is, however, to 
 be preferred. 
 
 Consistently M'ith the latest determined facts, the 
 cell or elementary -part is best defined as the smallest 
 mass of living matter possessing the essential life prop- 
 erties of reproduction, nutrition, growth, and develop- 
 ment. To such substance the terms " sarcode," " pro- 
 toplasm," "germinal matter," and "bioplasm" have 
 been applied, the first by Dujardin, the second by 
 Max Schultze and Eemak, and the third and fourth 
 by Eeale. 
 
 The term " sarcode " has nearly gone out of use, 
 and " protoplasm " has come to be largely used for 
 that part of the cell outside of the nucleus, without 
 regard to its living properties. The term " bioplasm," 
 on the other hand, has not yet received such exten- 
 sion of meaning, while it also etymologically defines 
 the substance it represents, and is therefore much to 
 be preferred. 
 
 The Nucleus of the Cell. — Tn the interior of most 
 cells are found one or more difli'erentiated masses of 
 bioplasm, usually round or nearly so, and more gran- 
 ular or darker in hue by transmitted light than the 
 
THE CELL DOCTRINE. 129 
 
 remainder of the cell, which are called nuclei. These 
 nuclei, although strikingly constant, are not invari- 
 ably present, as pointed out by Briicke,* in 1861, in 
 the cells of cryptogams, and confirmed by the earlier 
 discovery in 1854, of a non-nucleated amoeba (Amoeba 
 porrecta) by Max Schultze,t in the Adriatic Sea ; 
 also later by Hffickel;]^ and Cienkowski§ in their dis- 
 coveries in 1865, by the former of a non-nucleated 
 protozoon (Protogenes priraordialis) in the Mediterra- 
 nean, and by the latter of two non-nucleated monads 
 (Monas amyli and Protomonas amyli). Stricker's| 
 observations on the fecundated egg of the frog in- 
 cline him to adopt the view of Briicke, and omit 
 the nucleus in a theory of elementary organiza- 
 tion. Such facts as these prove erroneous the defini- 
 tion of a cell proposed by Leydig and Max Schultze, 
 " protoplasm surrounding a nucleus," and the defini- 
 tion more recently accepted by Virchow,T that a cell 
 is " a nucleus surrounded by a molecular blastema;" 
 though if we restrict ourselves to the cells concerned 
 in the organization of the higher animals, the latter 
 may be anatomically correct, but the former involves 
 the confusion already referi'ed to in the use of the 
 word " protoplasm," which is here applied to some- 
 
 * Briicke, B.,Die Elementar-organisraen, p. 18-22, 1861. 
 
 t Schultze Max, Organis. d. Polythalam. , 1854. 
 
 X Hseckel, Zeitschr. f. w. Zoolog., 1865, Bd. xv. 
 
 I Cienkowsky, Max Schultze's Archiv, 1865. 
 
 y Strieker, S., in vol, i, p. 8, Strieker's Histology, New Syden- 
 ham Society's Translation, London, 1870; also p. 504, vol. iii, 
 London, 1873. 
 
 \ Letter from Berlin, in Edinburgh Medical Journal, Febru- 
 ary, 1865. 
 
130 THE CELL DOCTRINE. 
 
 thing outside of the nucleus to the exclusion of the 
 latter, to which, if to anything, should be assigned 
 the term. 
 
 For the nucleus possesses pre-eminently three of the 
 properties of bioplasm named, nutrition, reproduc- 
 tion, and growth, and in it usually take place the 
 first steps towards the production of new cells, in, 
 first, its increase of size through nutrition, and 
 second, by fission, which subsequently extends to the 
 remainder of the cell. Indeed the chief function of 
 the nucleus has been heretofore considered as that of 
 the reproduction of the cell. But this is by no means 
 invariably the case, as indeed it is clear should not 
 be, when we recall the properties of bioplasm or 
 germinal matter. For although the nucleus is a sep- 
 arate dift'erentiated portion of bioplasm, it does not 
 in every cell comprise the whole of the bioplasm of 
 that cell. This is perhaps best illustrated by the 
 pus-cell and colorless blood-corpuscle, which are pure 
 bioplasm, but which still contain within them sepa- 
 rate centres of germinal matter or nuclei. Consist- 
 ently with this fact, the pus-cells or white blood-cells 
 multiply not necessarily through a primary fission 
 of the nucleus, but often by separating a portion of 
 the external bioplasm, which becomes an independent 
 cell /with the endowments of its predecessor. See 
 Fig. 7, 8, 9, 10, of frontispiece. This fact has further 
 a very important illustration in the fecundated germ 
 or ovum of sexual generation. It is now universally 
 admitted that the non-fecundated germ is a distinctly 
 nucleated cell, and it is almost as generally acknowl- 
 edged that immediately after fecundation the nu- 
 
THE CELL DOCTRINE. 131 
 
 cleus disappears, to be replaced, however, by a new 
 one, under favorable conditions, which appears to 
 take no part in the subsequent cleavage processes.* 
 
 Recent descriptions of the nucleus include in its 
 anatomy a nuclear membrane, which is described by 
 Auerbach as a somewhat thick, highly refractile, 
 doubly contoured membrane, which appears to be 
 less distinctly separated from the cell protoplasm 
 than from the exterior of the nucleus. This mem- 
 brane is regarded by Auerbach as having been formed 
 about the original droplike nucleus by the differ- 
 entiation of the inmost layer of the protoplasm into 
 a species of interior cell membrane. According to 
 Klein, it is composed of an outer thicker portion, 
 which is the limiting membrane proper, and closely 
 connected with it an inner more or less incom- 
 plete layer, which is a peripheral condensation of 
 the intranuclear network, with which it is connected 
 by longer or shorter threads. According to Auer- 
 bach, the nuclei first appear as clear spaces, vacuoles 
 
 * According to Prof. Strieker (" Development of the Simple 
 Tissues," in vol. iii, of " Human and Comparative Histology," 
 New Syd. Soc. Ed.), precise statement to the effect that the germi- 
 nal vesicle is persistent and becomes transformed into the nucleus 
 of the cleavage cells, has only been made by Johann Muller in the 
 case of Entoconcha mirabilis (Monatsberichte der Berliner Akade- 
 mie, September, 1851). But in recording this fact Strieker seems, 
 as many more recent writers have done, to have entirely overlooked 
 the much earlier observation of Martin Barry, who distinctly as- 
 serts (Philosophical Transactions, London, 1840, p. 529), that " the 
 germinal vesicle does not burst, or dissolve away, or become flat- 
 'tened, on or before the fecundation of the ovum, as hitherto sup- 
 
182 THE CELL DOCTRINE, 
 
 filled with a tenacious fluid mass possessing no dis- 
 tinct wall. Each droplet then acquires a membrane 
 by dift'erentiation of the inmost layer of cell proto- 
 plasm and nuclei, and intermediary granules after- 
 wards make their appearance. Once differentiated, 
 the nuclear membrane is an integral part of the nu- 
 cleus, constituting the latter a true vesicle, isolable 
 as a whole by mechanical means.* 
 
 The Nucleolus. — Very commonly also, though not 
 invariably attending it, a second differentiated mass 
 of matter is found within the nucleus, to which the 
 term nucleolus is applied. According to Beale, it is 
 possessed of like endowments, and is supposed to be 
 the most recently formed bioplasm, the non-vitalized 
 circulating albumen of the blood being converted 
 through the agency of pre-existing bioplasm into 
 the latter substance. If the cell normally develop, 
 the nucleolus growing becomes the nucleus, the lat- 
 ter being gradually oxidized upon its exterior and 
 converted into the cell-contents and cell-wall, while 
 a j'ounger centre of germinal matter takes the place 
 of the original nucleolus. This living matter exhibits 
 the important property of being stained by weak so- 
 lutions of various coloring matters, as carmine, anilin, 
 etc., the younger matter taking on the deeper stain, 
 and by these means its demonstration is rendered 
 strikingly easy. In rapidly growing cells, a still 
 younger centre of bioplasm may sometimes be demon- 
 strated within the nucleolus, while the nucleus re- 
 mains a distinctly differentiated mass capable of also 
 
 * Auerbach, Organologisohe Studien, Breslau, 1878-4. 
 
THE CELL DOOTRINB. 133 
 
 being stained. To this youngest centre of bioplasm, 
 the term "nucleoleolus" might not be inappropriately- 
 applied. 
 
 Klein has announced in his recent paper " On the 
 Structure of Cells and ISTuclei " (Quart. Journ. Mi- 
 croscop. Sci., July, 1878), that after very prolonged 
 examination he has arrived at the conclusion that 
 these large particles (nucleoli) are due to one of two 
 things : in some instances they are distinctly thick- 
 enings of the nuclear network of fibrillse demonstra- 
 ted by Frommann and Heitzmann, and confirmed by 
 Flemming, Hertwig, E. Van Beneden, Klein himself, 
 and others, or they are merely due to the shrivelling 
 up and intimate fusion of a part of this network. 
 
 Auerbach supposes that the nucleolus is formed 
 by the aggregation about a centre, of nucleolar sub- 
 stance, which is derived either from the periphery of 
 the nucleus itself or from the inmost layer of cell 
 protoplasm. According to him, nucleoli may also 
 multiply by fission. This division is associated with 
 a movement of the new nucleoli through the nu- 
 clear ground-substance, the cause of which is not 
 understood. ' The reverse, or the fusion of several 
 nucleoli into one, also occurs. Auerbach says also 
 that many facts speak for the identity of nucleolar 
 substance and cell protoplasm. In optical appearance, 
 nucleoli and the substance of young cells agree, and 
 vacuolation may occur in either, large nucleoli being 
 seldom free from clear spaces. Both are amoeboid, 
 the movements in nucleoli having been described by 
 many observers. Lastly, nucleoli have, as Auerbach 
 himself shows, that characteristic of vital protoplasm, 
 
 12 
 
134 THE CELL DOCTRINE. 
 
 the power of multiplication by division. That is, 
 nucleoli have all the capabilities of elementary or- 
 ganisms, and are in truth cytodes. Regarded in 
 this light, they are real daughter cells, which have 
 arisen by an endogenous process, and the nucleus is 
 the chamber in which they develop. It is now 
 merely neces«ary for them to find a way out through 
 the body of the mother cell, in order to begin life as 
 independent beings. That^his method of increase 
 has become obsolete in the cases of a majority of cells 
 of higher adult animals, or perhaps only occurs in 
 pathological processes, may be quite true, according 
 to Auerbach, without offering any obstacle in the 
 way of such a hypothesis. In the specialization of 
 function which appears as we ascend the animal 
 series new means of gaining the same end present 
 themselves, while the old vanish or are made use of for 
 other purposes. The phases in the act of propaga- 
 tion of a unicellular organism may be less significant, 
 and have a far different outcome in a unit cell of a 
 more complex creature.* 
 
 The fact of the total or partial disappearance of 
 the nucleus or germinal vesicle shortly before or im- 
 mediately after fecundation, has been amply con- 
 firmed by recent observers, although there are some 
 slight differences in the exact mode of its acceptance. 
 The most important recent contributions on the sub- 
 
 * Auerbach, Organologische Studien, Breslau, 1873-4, or see 
 abstract of Auerbach's paper, by Priestley, in vol. xvi, Quart. 
 Jour. Microsc. Soi., 1876, whence I have obtained the above views 
 of Auerbach with regard to nuclei and nucleoli. 
 
THE CELL DOCTRINE. 135 
 
 jeet have been by Auerbach,* Strassburger,t Hert- 
 wig,:]: and Van Beneden,§ to whom may be added 
 Butschli,|| Oel]acher,T[ Kleinenberg,** and Balfour.ft 
 Under the influence of the fertilizing act the ovnm 
 again becomes nucleated, the nucleus arising in a 
 fusion of pronuclear bodies, one of which may pos- 
 sibly be derived from the fertilizing element (sper- 
 matozoid). The nucleus then begins series of changes, 
 about which most observers are agreed, but for the 
 details of which the reader is referred to the sources 
 named in the footnote. 
 
 * Organologische Studien. Breslau, 1873-4. 
 
 t TJeber Zellbildung und Zelltheiluiig, Jena, 1875. 
 
 J Beitrage zur Kenntniss der Bildung, Befruchtung, und Thei- 
 lung des thiereschen Eies, Morpholog. Jahrbuch, 1, 1875. 
 
 ^ La Maturation de I'oeuf, la Pecondation et les Premieres 
 Phases du Developpement Embryonaire des Mammifferes, d'aprds 
 des Eecherches faites ohez le Lapin. Bruxelles, 1875. 
 
 Excellent abstracts of these four papers, by John Priestly, are 
 found in the Quart. Jour, of Microse. Sci., for July, 1878, vol. 
 xvi, new series. In the same number will be found an original 
 paper by Van Beneden, entitled " Contributions to the History of 
 the Germinal Vesicle,. and of the first Embryonic Nucleus," in 
 which he compares the views of Hertwig with his own. 
 
 II Vorlaufige Mittheilung iiber Untersuchungen betreffend die 
 Ersten Entwickelungsvorgange in Befruchteten Ei von Nemato- 
 den und Schnecken, Zeitsch, fiir Wiss. Zoologie, Bd. xxv ; and 
 "Vorlaufige Mittheilung Einiger Eesultate von Studien iiber die 
 Conjugation der Infusorien und die Zelltheilung, Zeitsch. fiir 
 Wiss. Zoologie, Bd. xxv, 1875. 
 
 ^ Beitrage zur Geschichte des Keimblasohens im Wirbelthierei, 
 Archiv fiir Mikrosk. Anat., Bd. viii, 1872. 
 ** On the Anatomy and Development of the Eresh-water Hydra. 
 Leipzig, 1872. 
 If Balfour, Developmental History of Blasiiiobranch Fishes, in 
 the Journal of_ Anatomy and Physiology, January, 1876. 
 
136 THE CELL DOCTRINE. 
 
 As already stated, previous to the researches of 
 Miiller alluded to, no one doubted the disappearance 
 of the germinal vesicle after fecundation. This was 
 thought to have been established by Purkinje* and 
 Von Baer.f But immediately after Miiller made his 
 announcement, others followed in its confirmation. 
 Among these were Leydig,:): Gegenbauer,§ Fol,|| Leuc- 
 kart,l[ Pagenstecher,** Mecznikow,tt H8eckel,:l::}:Kbl- 
 liker,§§ and Van Beneden,!! as the result of his earlier 
 researches. Still later, however, of the above-named 
 
 * Purkinje, Symbolse ad ovi avium historiam ante incuba- 
 tionem, 1825. 
 
 ■j- Baer, C. E. v., Untersuch. u. die Entwicklungsgescb. der 
 Pische, 1835 ; and Untersuch. u. iJie Entwicklungsgescb. der 
 Thiere, Bd. ii, Konigsberg, 1828. 
 
 J Leydig, Ueber den Bau und die Systematiscbe Stellung der 
 Koderthiere, Zeit. fur Wiss. Zool., Bd, vi, p. 102, 1856. 
 
 J Gegenbauer, Beitrage zur Naheren Kenntniss der Siphono- 
 pboren, Zeit. fur "Wiss. Zool., Bd. v; Zur Lehre vom Genera- 
 tionsweehsel bei Medusen und Polypen, p. 24; Untersuch. iiber 
 Pteropoden und Heteropoden, Leipzig, 1855. Ueber die Ent- 
 wickelung der Sagitta, Halle, 1856. 
 
 I Fol, Die erste Entwickelung des Geryonideneies, Jenaischi 
 Zeitsch., Bd. vii, 1873, p. 474. 
 
 f Leuckart, Die Menschlichen Parasiten, Bd. ii, 2te Lief. p. 
 322, 1863. 
 
 ** Pagenstecher, Die Woehenen, Leipzig, 1865. 
 
 ft Mecznikow, Embryologische Studien an Insecten Zeitsch. 
 fur Wiss. Zoologie, Bd. xvi, p. 484, 1866. 
 
 JI Hffickel, Zur Entwickelungsgeschichte der Siphonophoren, 
 Utrecht, 1869. 
 
 §g KoUiker, Die Schwinimpolypen von Messina, Leipzig, 1853. 
 
 nil Van Beneden, Recherches sur la Composition et la Significa- 
 tion de I'oeuf basees sur I'Elude de son mode de Formation et des 
 Premieres Phfinomfinos Embryonaires, Mem. Couronne de I'Acad. 
 Roy. de Belgique, 1. xxxiv. 
 
THE CELL DOCTRINE. 137 
 
 more recent observers, Auerbach, Strassburger, 
 Oellacber, Kleinenberg, Biitschli, Balfour, and Van 
 Beneden, in accordance with fresh researches made 
 on account of the doubts which those of Oellacber 
 and Kleinenberg had created in his mind, all agreed 
 that the germinal vesicle disappeared entirely either 
 before or during fertilization. Hertwig and V-an 
 Beneden both furnish a carefully detailed account of 
 the steps in the destruction of the germinal vesicle, 
 the former in the unripe ova of Toxopneustes lividus, 
 and the latter in the ovum of the rabbit. While 
 agreeing in many particulars, they differ in their ac- 
 count of the final dissolution. According to Hert- 
 wig, the whole structure, after having become periph- 
 eral, disappears, leaving behind, of its contents, the 
 germinal spot, or nucleolus, which becomes the nucleus 
 of the ovum ready for the changes of fertilization. 
 Van Beneden, on the other hand, believes that all the 
 constituents of the germinal spot disappear in ioto. 
 
 It seems also that the view of Hertwig, that a part 
 of the germinal vesicle remains to form the nucleus 
 of the ovum, was previously suggested by Derbes and 
 Von Baer. The former, in lb47,* described the 
 ovarian ova as consisting of three zones, the germi- 
 nal spot, the germinal vesicle, and the yolk, of which 
 the middle one only disappears. Von Baerf also 
 states that in the case of echinoderms, the germinal 
 
 * Derbes, Observ. sur le Mocanisrae et le Phen. qui accomp. la 
 Formation de I'Embryon chez I'Oursin Comestible, Ann. des Sc. 
 Nat., Zoologie, 1847, vol. viii. 
 
 ■f C. B. V. Baer, Neue Untersuch., iiber die Entwickel. der 
 Thiere, Froriep's Neue Notizen, vol. xxxix, 1846. 
 
 12* 
 
138 THE CELL DOCTKINB. 
 
 spot remains as a nucleus of the ovum when the ger- 
 minal vesicle is no longer seen. 
 
 Similar statements were made by Leydig,* and 
 Bischoff'jt the former with regard to Piscicola, and 
 the latter in the case of mammals. 
 
 The Cell-contents and Cell-wall. — As cells grow older 
 and are farther removed from the bloodvessels which 
 nourish them, there is found to be, exterior to the 
 nucleus, a portion which no longer admits of staining 
 by carmine solutions of the strength which will tinge 
 the nucleus. Further, the extreme periphery of this 
 is often found condensed so as to present under the 
 microscope a double contour, and to form an actual 
 limitary membrane to the cell. To the former the 
 name " cell-contents " has come to be applied, and to 
 the latter, " cell-wall." 
 
 With regard to the " cell-contents," it is plain that 
 a strict adherence to the term would require to be 
 included the nucleus and nucleolus when present, 
 and such was the original scope of the term when a 
 cell was defined as a " closed vesicle or bag with cer- 
 tain ' contents/ among which is essentially a nu- 
 cleus,"' a definition now very properly rejected. It 
 is to this portion of the cell also, that the German 
 histologists of the present day apply the term "proto- 
 plasm," instead of to the nucleus and nucleolus, which 
 in many cells, at least, alone possess the endowments 
 suggested by the word protoplasm (^/owtot, first, T^kaaixa, 
 
 * Leydig, Zur Anatomie von Piscicola Geometrica, Zeitsch. f. 
 Wiss. Zoologie, vol. i, 1849. 
 f Bischoff, Entwickelungsgeschichte des Kaninchen eies, 1842. 
 
THE CELL DOCTRINE. 139 
 
 a thing formed). It is for this reason that I would 
 prefer to reject the term altogether, but it has come 
 to be 80 closely associated with this portion of the 
 cell, that such omission would now seem impossible. 
 
 It is at least probable that this " protoplasm " or cell- 
 contents, the portion of the cell exterior to the nu- 
 cleus, is derived from the latter by a change in its 
 structure and composition, a change which in the 
 absence of more accurate knowledge we may char- 
 acterize as of the nature of oxidation. But what- 
 ever this change is, its efl'ect is to alter entirely the 
 properties of the matter in which it has taken place. 
 So that it no longer possesses the power of growth 
 through active efforts of nutrition, that is, by con- 
 verting the pabulum of the blood into material like 
 itself, but continues to grow at the expense of the 
 nucleus or bioplasm, which is gradually converted 
 into it. It is this to which Beale has applied the 
 name of "dead" or "formed" material, but for 
 which I prefer the term non- germinal, since this ac- 
 curately marks the property which it has lost, and 
 it is not always lifeless in any other sense, because 
 in it still reside properties which are inconsistent i 
 with the state known as death. Thus the function 
 of the tissue of which the cell forms a part commonly 
 resides in the cell-contents or non-germinal matter, 
 as that of " contractility " in muscle and " neu- 
 ridity " in nervous tissues. In some situations it is 
 truly dead, as where it becomes the secreition of glands, 
 as milk and bile. 
 
 It has already been stated that the " cell-wall " 
 when present is simply condensed periphery of cell- 
 
140 THE CELL DOCTRINE. 
 
 contents, and is therefore a part of the formed or 
 non germinal matter, and is in no way essential to 
 the constitution of the cell. 
 
 In structure the cell-wall when present is usually 
 homogeneous, transparent, in a word structureless. 
 Recent observations have, however, shown this to be 
 not invariable. Thus, it is not difficult to demon- 
 strate with the higher powers certain lines or strise 
 in the outer thickened edge of the columnar cells 
 capping the villi of the small intestine, which are 
 perhaps correctly interpreted by Funke, KoUiker, 
 and others, as porous canals in the cell-wall, through 
 which the tine particles of the emulsified fats are 
 absorbed. These may at least be discovered occupy- 
 ing corresponding situations with great distinctness. 
 Schroen has also described similar markings in the 
 thickened cell-wall of the rete Malpighii of the 
 human skin. 
 
 Intercellular Substance. — Closely allied to the cell- 
 M^all is the so-called intercellular substance of tissues. 
 Although it is true that all tissues originate from 
 cells, yet there are comparatively few which in their 
 perfect state are composed purely of cells, but the 
 latter are more or less separated by a substance be- 
 tween them. Thus cartilage or " gristle " is com- 
 posed of cells and an intercellular substance, which 
 is either hyaline or fibrous, and all the connective 
 tissues, under which are included bone, cartilage, 
 already alluded to, white fibrous tissue, yellow elastic 
 tissue, and even teeth, are similarly composed of 
 cellular elements, and a something between them, 
 which is either homogeneous or structured. 
 
THE CELL DOCTRINE. 
 
 141 
 
 The mode of origin of this intercellular substance 
 has given rise to considerable discussion. Schwann 
 assumed that there originally existed spindle-cells, the 
 caudate corpuscles, and that out of these cells, fas- 
 ciculi of connective tissue were developed by split- 
 ting up of the body of the cell. 
 
 Fig. 18. 
 
 C 2 
 
 A, BuDdle of common, wavy, connective tissue (intercellular substance) split- 
 ting at its end into fine fibrils. B, Diagram of the development of connective 
 tissue, according to Schwann, a, Spindle-shaped cell (caudate corpuscle, fibro- 
 plastic corpuscle of Lebert), with nucleus and nucleolus, d. Cleavage of the body 
 of the cell into fibrils. C, Diagram of the development of connective tissue, 
 according to Henle. a, Hyaline matrix (blastema) with nucleolated nuclei regu- 
 larly distributed through it. 6, Fibrillation of blastema (direct formation of 
 fibrils), and transformation of the nuclei into nucleus-fibres. 
 
 Henle thought that originally there were no cells, 
 but nuclei only were developed in the blastema at 
 certain intervals, while the fibres which afterwards 
 appeared were produced by a direct fibrillation of 
 the blastema, and that while the intermediate sub- 
 stance was thus being differentiated into fibres, the 
 nuclei gradually became elongated, so as at length to 
 
142 
 
 THE CELL DOCTRINE. 
 
 run into one another, and thus give rise to peculiar 
 longitudinal fibres {nucleus-fibres or kernfasern). 
 
 Reichert contended that there were cells in great 
 abundance between which was deposited intercellular 
 substance, with which the membrane of the cells be- 
 came subsequently blended, reaching thus a stage in 
 which there was no longer any boundary between 
 the cells and the intermediate substance. The nuclei 
 he thought also disappeared in some instances. The 
 intercellular fibres he said were a false interpretation 
 of an optical image. 
 
 Virchow, with Schwann and against Henle, be- 
 
 Diagram of the development of connective tissue, according to Virchow's in- 
 vestigations. A, Earliest stage, hyaline basis (intercellular) substance, with 
 largish cells (connective tissue corpuscles) ; the latter drawn up in rows at regular 
 intervals ; at iirst, separated, spindle-shaped and simple ; at a later period, anas- 
 tomosing and branched. B, More advanced stage -, at a, the basis-substance which 
 has become striated (fibrillaced) presents a fasciculated appearance on account of 
 the cells imbedded in it in rows, the cells becoming narrower and smaller; at 6, 
 the striation of the basis-substance has disappeared under tlie influence of acetic 
 acid, and the fine and long-anastomosing fibre-cells (connective tissue corpuscles), 
 still retaining their nuclei, are seen. 
 
 lieves that spindle-shaped cells indisputably exist, 
 and with Henle and Reichert and against Schwann, 
 
THE CELL DOCTRINE. 143 
 
 a splitting up of the cells into fibres does not occur, 
 but that a previously homogeneous intercellular sub- 
 stance becomes fibrillated, and that the cells them- 
 selves preserve their integrity. In young connective 
 tissue, cells uudoubtedly exist, with at least their 
 more important parts as nuclei and protoplasm, but 
 in fully formed fibrous tissue the only portion of the 
 cell which I have been able to satisfy myself, in an 
 almost daily study of healthy and diseased struc- 
 tures, is constantly present, is the nucleus. 
 
 Max Schultze, in Germany, Beale, in England, and 
 Leidy, in this country, believe the intercellular sub- 
 stance to originate as the cell-contents and cell-wall 
 by a conversion of the nucleus or bioplasm at its 
 periphery, and a pushing oft" of this converted 
 matter by the deposition of new bioplasm within the 
 nucleus. In fact, according to them, the intercellu- 
 lar substance is simply the oldest cell-wall or formed 
 material, under which term Beale consistently in- 
 cludes all intercellular substance. See Figs. 11, 12, 
 frontispiece. 
 
 This view seems to me also to be most consistent 
 with observation, and until something more reason- 
 able is oftered I shall adopt it. One of the most 
 potent arguments in its favor is the fact that the 
 cell-wall and intercellular substance are often so 
 closely continftous that they cannot be separated, 
 either visually or by dissection. On this account 
 Beale has also described a " cell " or " elementary 
 part " of cartilage and similar structures, as includ- 
 ing in its formed material the intercellular substance 
 extending to a point midway between it and its 
 neighbor. 
 
144 THE CELL DOCTRINE. 
 
 The Strxidure of Cells. — As to structure, cells have 
 been heretofore described as structureless, or vari- 
 ously granular, and with powers not exceeding 250 
 diameters, they may still be so described. Few cells 
 even with these powers are structureless, while on 
 the other hand, a highly granular condition of a cell 
 is considered indicative of some pathological change, 
 except in the case of nerve-cells, which in many 
 situations are admittedly highly granular in the 
 normal state. The same may be said of the nucleus. 
 Occasionally, however, even previous to 1867, certain 
 nerve-cells were described as striated in appearance. 
 Examples of structureless cells are most striking in 
 the unicellular organism, as the amoeba (Fig. 16, front- 
 ispiece), in which we have a structureless nucleated 
 mass, which owes whatever of structure it possesses 
 to foreign particles, which it takes up as food. So far 
 as the structure of the elementary part of the more 
 complex organisms, however, is concerned, the recent 
 discoveries, al ready described (see p. 11 7) as discernible 
 by a power as low as 300 diameters, demand a total 
 change in the description of the structure of cells. 
 Henceforward we must describe not only the nucleus 
 but also the cellular substance (protoplasm) as fibrillar 
 in structure, made up of a network of delicate fibres 
 the meshes of which are filled with an " interfibril- 
 lar " or " ground substance," which is structureless, 
 and that the fibrillse of the intracellular and intra- 
 nuclear networks afe continuous. And if Klein be 
 correct we must define the nucleoli as merely local 
 thickenings, natural or artificial, of the intranuclear 
 network. The intranuclear networks are much more 
 
THE CELL DOCTRINE. 145 
 
 distinct than the intracellular. See plate at end of 
 volume. 
 
 TTie Shape of Cells. — The shape of cells is extremely 
 varied. In its fully developed state each tissue is com- 
 posed of cells which may be said to be characteristic of 
 it. First, the typical form of a cell may be said to be 
 spherical, and this is the shape of all young cells in 
 whatever situation found. See Fig. 10, frontispiece. 
 Second, in glandular tissue, where perhaps cells are 
 changing more rapidly than in any other situation 
 in health, their deviation from the round shape is 
 only such as results from mutual compression, forming 
 more or less polygonal cells, as seen in Fig. 3, p. 39. 
 ITiird, in epithelial structures we have upon the ex- 
 treme periphery either flat scales containing a small 
 proportion of bioplasm (nucleus) in proportion to the 
 non-germinal matter (cell-contents), and of irregular 
 outline, forming the so-called squamous epithelium. 
 Figs. 3, 4, 5, 6, frontispiece; or fourth, similar scales, 
 of regular outline, many-sided and with their edges 
 so adapted as to form a pavement-like structure, 
 forming tessellated epithelium ; or fifth, elongated nu- 
 cleated cells, which from their shape are called colum- 
 nar cells. Sixth, in certain situations, as the respira- 
 tory passages, these columnar cells are further provid- 
 ed with hairlike prolongations, known as cilia, which 
 in health exhibit a constant waving motion, whence 
 the cells are called ciliated cells. Wherever columnar 
 cells are present in successive layers (as is usually the 
 case), they lose their characteristic shape and ap- 
 proach more and more the spherical outline as we 
 recede from the surface, until the deepest and there- 
 is 
 
146 THE CELL DOCTRINE. 
 
 fore j'oungest cells are again spherical. Seventh, in 
 nervous tissues again, we meet cells which from their 
 prolongations, which may be one or many, are called 
 folar cells, and unipolar, bipolar, or multipolar, ac- 
 cording to the number of processes they possess. 
 Eighth, in the so-called connective tissue again, we 
 have a variety in the shape of the cells. Thus in 
 areolar tissue or connective tissue proper, we have 
 young round cells composed almost wholly of germi- 
 nal matter, exhibiting amoeboid movements and all 
 the characters of the leucocyte or colorless corpuscle 
 (Fig. 10, frontispiece), as well as the elongated spin- 
 die shaped nucleated cell, so characteristic as to have 
 long ago received the name connective tissue corpuscle 
 (Fig. 16, frontispiece, Fig. 18, B.). These latter cells 
 also possess prolongations, which unite with those 
 extending from adjacent cells, and being hollow thus 
 form a canalicular system, of exceeding fineness, 
 which is believed to be capable of conveying nutrient 
 juices in the absence of bloodvessels of sufficient size 
 to conduct the corpuscles of the blood. The appear- 
 ance of this system is shown in Figs. 16 and 19, from 
 Virchow's Cellular Pathology. Ninth, the cells of 
 striated muscular tissue exhibit a prolonged oval shape, 
 sometimes resembling that of the connective tissue 
 corpuscle, while the cells of unstriped muscular tissue 
 are typical spindle-cells, with bellied centres and 
 staff-shaped nuclei. 
 
 Again, in cartilage we have cells exhibiting various 
 modifications of the spherical shape, while the cells 
 of bone give us a tenth form. These are contained 
 in correspondingly irregular cavities in its substance. 
 
THE CELL DOCTRINE. 147 
 
 and are almost fantastic in their irregularity, ex- 
 hibiting also prolongations which unite with those 
 of neighboring bone-cells, and with the Haversian 
 canals which conduct the bloodvessels through bone. 
 The shape of the cells through whose agency the 
 teeth are formed is also seen to be peculiar, those 
 whence the dentine is developed being provided with 
 a single long process, giving an eleventh form of cell. 
 Those producing the enamel are columnar, while the 
 crusta petrosa, or portion of bone-like substance cover- 
 ing the fang, contains cells similar to those of bone. 
 Finally, the cells of adipose or fatty tissue require 
 allusion. They are spherical or compressed vesicles 
 or sacs of considerable size, are filled with oil, and 
 exhibit in consequence a brilliant, highly refracting 
 character, under the microscope, indicated by a broad 
 dark border and a transparent centre. In the begin- 
 ning they are in no way dilferent from other young 
 cells, but, according to Beale, their bioplasm, instead 
 of being converted into the ordinary non-germinal 
 matter of albuminous composition, undergoes a fatty 
 conversion, in the course of which it gradually di- 
 minishes in size and is thrust towards the wall of 
 the cell, where it may sometimes be demonstrated 
 by staining as a small flattened nucleus. The oil 
 thus produced is termed by Beale secondary formed 
 material, to distinguish it from the albuminous non- 
 germinal matter. The same term is applied by him 
 to the secondary product, starch, found in the shape 
 of concentrically laminated granules in many vegeta- 
 ble cells. According to most other histologists, how- 
 ever, the fatty contents of the /a<- vesicles are an infil- 
 
148 THE CELL DOCTRINE. 
 
 tration of fat from the blood, superadded to the pro- 
 toplasm or cell-contents, pushing the latter with the 
 nucleus to one side, without substituting it or being 
 derived directly from it as is alleged by Beale. 
 
 In -pathological formations all the different forms of 
 cells here alluded to are met with, and there is now 
 no special type of cell which is known by its shape 
 to have a pathological impression. It is rather by 
 the rapidity of growth of cells, their arrangement 
 and relation to the intercellular substance, as well as 
 peculiarities in the latter substance itself, that we 
 know a structure to be a pathological formation. 
 The " cancer-cell," which was so long an object of 
 wonder and fear, and eagerly sought for as such, is 
 no longer acknowledged to be anything peculiar as 
 to form. At the same time, when cells from a sus- 
 pected growth are observed to be very large, to con- 
 tain numerous nuclei or centres of bioplasm, and to. 
 exhibit great variety in shape, we have evidences of 
 that rapidity of growth which is more or less char- 
 acteristic of malignant formations. 
 
 The Size of Cells. — This is likewise extremely vari- 
 ous. They may be particles of such extreme minute- 
 ness as to be recognized as mere dots by the highest 
 powers of the microscope, the smallest particles of 
 germinal matter measured by Dr. Beale being less 
 than the T^^j'oTfg of an inch (.000024 mm.) in diame- 
 ter, while the largest epithelial scales are j^g of an 
 inch (.1 mm.) in diameter, and the cells of morbid 
 growths often reach the ^^^ of an inch (.127 mm.). 
 The human ovum, which may be regarded as a typi- 
 cal cell, with nucleus, nucleolus, and contents, varies 
 
THE CELL DOCTRINE. 149 
 
 from the ^i^ to yj-j- of an inch (.105 mm. to .21 
 mm.). The smallest particles of germinal matter 
 above alluded to would not be called cells in the or- 
 dinary sense of the word, but they are such consist- 
 ently with ou(r definition, and it must moreover be 
 remembered that the term is only applied to such 
 particles of matter endowed with the life properties 
 of reproduction, nutrition, growth, and development. 
 No particle of oil, inorganic or other matter, which 
 does not possess these properties can be characterized 
 as a living cell, whatever its size. 
 
 Pure germinal matter is rarely seen in masses as 
 large as the 5 J^ of au inch (.05 mm.), since it usually 
 breaks up into smaller masses to form independent 
 cells before it reaches this size. As constituting the 
 nuclei of fully formed cells, it is usually from the 
 bttW to s^'j-jT °^ ^^ inch (004. mm. to 008. ram.) in 
 diameter. While nuclei exhibit less variation in size 
 than do the cells, they are also more constant in shape, 
 being generally round or oval. Sometimes, however, 
 they also exhibit a stellate shape. 
 
 The Origin of Cells. — It is to be regretted that this 
 most important question as to the exact origin of 
 cells is not yet definitely settled. A very short time 
 ago the proposition omnis cellula e celluld wa,% thought 
 to have been abundantly proven, and that all living 
 things come from previously existing things, was 
 generally admitted. But although this view has been, 
 in the conception of some, shaken by more recent ex- 
 periment, it still remains the only law of cell forma- 
 tion in the minds of most physiologists, and I be- 
 lieve there are none who deny that it forms in all 
 
 13* - 
 
150 THE CELL DOCTRINE. 
 
 the higher forms of animal and vegetable life the 
 only method of cell genesis which is constantly before 
 us, while the phenomena of spontaneous generation 
 are confined to the creation of the lowest vegetable 
 and animal organisms, so that the proposition omnis 
 cellula e celluld may be now considered as generally 
 accepted. Prof. H. Charlton Bastian remains the 
 most eminent English supporter of the doctrine of 
 spontaneous generation, against whom Huxley, Rob- 
 erts, Tyndall, Beale and others have directed arti- 
 cles and experiments. 
 
 In the division of cells to produce young cells, it 
 is usually in the nucleus that the segmentation first 
 begins, extending thence to the protoplasm outside of 
 it, although this is not invariable. For any portion 
 of the bioplasm of a cell may grow, separate and form 
 a young cell. It is the bioplasm or germinal matter 
 alone, however, which can give rise to the cell, and 
 never the non-germinal matter or formed material. 
 It is seldom, also, that we see in the animal cell, ex- 
 cept in the segmentation of the fecundated ovum, 
 that symmetrical division of the nucleus into two, 
 these into four, these into eight, and so on, as is con- 
 stantly seen in the vegetable cell, but it is rather a 
 budding»and subsequent dropping off of portions of 
 bioplasm which become young cells, and which al- 
 most always assume the spherical form when allowed 
 to float .freely (see Fig. 10, of frontispiece). 
 
 Strasiburger,* in his recent work on Cell Formation 
 and Cell Division, admits three methods of increase 
 
 * Ueber Zellbildung und Zelltheilung, Jena, 1876. 
 
THE CELL DOCTRINE. 151 
 
 of cells, — cell division, free cell formation, and re- 
 newal (vollzellbildung) of cells. He says that in the 
 animal kingdom cell division seems to be the only 
 authenticated mode of increase of cells. Of methods 
 of free cell formation, only a few instances are re- 
 corded in vegetables. The last method, renewal or 
 rejuvenescence, has reference rather to the complete 
 formation or development of cells than to their 
 origin. 
 
 Nutrition of Cells. — In the nutrition of the cell, the 
 pabulum comes to it from the periphery, being 
 strained through the formed material. The new 
 germinal matter takes its place in or near the centre 
 of the original mass, constituting, according to Beale, 
 a new centre of germinal matter, which may be the 
 nucleus, if no other circumscribed centre be present, 
 or the nucleolus, if it be deposited within such a centre. 
 Other new centres, according to him, may again take 
 position within these, and assume the relation of nu- 
 cleolus to the original nucleolus, which now becomes 
 the nucleus, an older centre of germinal matter ; 
 while the original nucleus has probably been con- 
 verted into the second constituent of the cell, the 
 formed material. If the nucleolus be what Klein con- 
 siders it, a mere thickening of the intranuclear net- 
 work referred to, this order of succession in the for- 
 mation of differentiated centres of germinal matter 
 is of course impossible, and it can only be said that 
 the new matter takes its position towards the centre 
 of the cell mass. 
 
 Amceboid Movement (Diapedesis). — Germinal mat- 
 ter, when free and living, exhibits a power of move- 
 
152 THE CELL DOCTRINE. 
 
 ment, botfi in portions of its substance, producing 
 changes in shape, and in its entire mass, resulting 
 in changes of position. The former, and probably, 
 also, the latter, may have for its object the ob- 
 taining of pabulum, as is seen in the amoeba, when 
 it embraces by its protrusions a particle of nutri- 
 tive matter. These movements are less decided in 
 the cells of the higher animals, yet they are of con- 
 stant occurrence, as in pus and white corpuscles, and 
 when thus occurring they are spoken of as " amoeboid 
 movements." Allied or identical with this second 
 class of movements, are those of undoubted occur- 
 rence in white blood-corpuscles, first observed by 
 Addison,* Waller,t and Cohnheim,:j: whereby these 
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 * Addison, Physiological Researches, London, 1841. 
 
 f Waller, London, Dublin and EdinBurgh Philosophical Maga- 
 zine, vol. xxix, 1846, pp. 271 and 398. 
 
 J Cohnheim, Ueber Entzilndung, und Eiterung, Virch. Arch. 
 Bd. xl, 1867, p. 1. 
 
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156 THE CELL DOCTRINE. 
 
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INDEX. 
 
 Addison, 114 
 Amcsba, 144 
 
 Amoeboid movement, 151 
 Aristotle, 13 
 Arndt, 121 
 Arnold, 26 
 Auerbach, 133 
 Author's views, 127 
 
 B. 
 
 Baumgartner, 26 
 
 Barry, Martin, 48 
 
 Beale, 83 
 
 Beneden, Van, 121 
 
 Bennett, 61 
 
 Bergmann, 44 
 
 Bibliography, 152 
 
 Bioplasm or Germinal Matter, 84 
 
 Borellus, 16 
 
 Bowman, 64 
 
 Briicke, 81 
 
 Butschli, 120 
 
 C. 
 
 Cell, Leydig's definition of, 80 
 M. Schultze's " " 80 
 VirchoVs " " 67 
 author's " " 128 
 
 Cell doctrine, present state of, 127 
 formation, 150 
 division, 150 
 nutrition of, 151 
 contents, 138 
 wall, 138 
 
 structure of, 140 
 Cell, or elementary paj-t in dis- 
 ease, 94 
 Cells, structure of, 144 
 shape of, 145 
 size of, 148 
 in pathological formations, 
 
 148 
 origin of, 149 
 and nuclei, new views on the 
 
 structure of, 117 
 polygonal, 145 
 young, 145 
 
 ciliated epithelial, 145 
 columnar " 145 
 squamous " 145 
 tessellated " 145 
 of adipose tissue, 147 
 of bone, 146 
 
 of connective tissues, 146 
 of nervous tissue, 146 
 of striated muscular tissue, 
 
 146 
 of unstriped muscular tissue, 
 146 
 Cohnheim, 114 
 
 Compound microscope, invention 
 of, 15 
 
198 
 
 INDEX. 
 
 D. 
 
 Diapedesis, 151 
 Dujardin, 76 
 Dutrochet, 29 
 
 E. 
 
 Eberth, 122 
 Eimer, 123 
 Elastic tissue, yellow, 71, 92 
 
 P. 
 
 Pallopius, 13 
 Flemming, 121 
 Formed material, 87 
 
 " secondary, 90 
 
 Frommann, 118 
 
 G. 
 
 Galen^ 13 
 
 Germinal matter, 84 
 Globular theory, the, 21 
 Goodsir, 51 
 
 H. 
 
 Haeckel, 77 
 Haller, 17 
 Heitzmann, 118 
 Henle, 44 
 Hertwig, 120 
 Hodgkin, 28 
 Home, Sir Everard, 25 
 Hooke, 17 
 Huxley, 54 and 104 
 
 Illustrations, list of, xi 
 Intercellular substance, 91, 140 
 
 K. 
 
 Klein, 123 
 Kupfer, 119 
 
 Leeuwenhoek, 17 
 
 M. 
 
 Malpighi, 16 
 Mayzel, 120 
 Meyen, 30 
 Milne, Edwards, ■25 
 
 N.. 
 
 Network, intracellular, 144 
 intranuclear, 131 and 144 
 
 Norris, 116 
 
 Nucleus, 128 
 
 discovery of, 30 
 
 Nucleolus, 132 
 
 " new explanation of, 125 
 
 Nucleus fibre, 142 
 
 Nuclear membrane, 131 
 
 Oken, 21 
 
 O. 
 
 Plate, description of, 201 
 Preface to second edition, vii 
 
 to first " ix 
 
 Prochaska, 24 ^ 
 
 Protoplasm, 138 ' '^ ^ 
 
 ofM. Schultze, 76 
 
 E. 
 
 Baspail, 29 
 Keichert, 44 
 Bemak, 54 
 Robin, 98 
 
s. 
 
 Sarcode of Dujardin, 76 
 Schleiden, 32 
 Schwalbe, 119 
 Schwann, 32 
 Strassburger, 120 
 Strieker, 116 
 Swammerdam, 16 
 
 Tissues, formation of, 91 
 Todd, 64 
 
 INDEX. 
 
 Tubercle, 97 
 
 Virchow, 65 
 
 Waller, 114 
 Wolff, 19 
 
 199 
 
 V. 
 
 w. 
 
('^!a!') / 
 
EXPLANATION OF PLATE. 201 
 
 EXPLANATION OP PLATE, 
 
 ILLTTSTRATINQ DK. KLBIN'B PAPBR, " OBSERVATIONS ON THE 
 
 STRUCTURE OF CELLS AND NUCLEI." 
 « 
 
 (From the Quarterly Journal of Microscopical Science, for July, 1878.) 
 
 Figures 1-11 (incl.) refer to preparations of stqmnch, 12-20 to 
 those of mesentery of newt. For method of preparing see text. 
 All figures are represented as seen on Hartnack's small stand with 
 eye-piece III, and Zeiss's objective P. 
 
 Fig. 1 represents a goblet cell ; the intranuclear network is well 
 shown, and also the fibrils passing from this into the upper and 
 lower part of the cell. 
 
 FiQ. 2. — The intranuclear network separated from the membrane 
 of the nucleus. 
 
 Fig. 3. — A goblet-cell (like that of 1) as seen obliquely from 
 above, showing the intracellular network. 
 
 Fig. 4. — The intracellular network looked at vertically from 
 above. 
 
 Fig. 5. — Isolated nucleus showing the intranuclear network. 
 
 Fig. 6. — A gland-cell, showing the dense network of fine fibrils 
 of the cell-sabstance ; the nucleus has escaped, but there are still 
 left a few fibrils, probably connecting the two networks, viz., the 
 intranuclear and the intracellular. 
 
 Fig. 7. — ^An isolated nucleus of a gland-cell ; the wall of the 
 nucleus is broken at one place and the intranuclear fibrils are seen 
 passing outwards. 
 
 '- Fig. 8. — A connective tissue corpuscle — endothelial plate — seen 
 in profile ; both the intracellular fibrils and those of the intra- 
 nuclear network are well shown. 
 
 Fig. 9 — A similar cell seen from its broad surface. 
 
 Fig. 10 — Portion of a cell ; the intranuclear network shrunk. 
 
 Fig. 11. — An epithelial cell; the intracellular fibrils are well 
 shown. The top of the cell is seen in an oblique direction, and 
 
202 EXPLANATION OF PLATE. 
 
 the network of fibrils is therefore brought into view. Prepara- 
 tion treated with Miiller's fluid, and then with mixture of chromic 
 acid and spirit ; see text. 
 
 Fig. 12. — Isolated endotheliul plate of surface of mesentery. 
 The intracellular and intranuclear networks of fibrils are well 
 shown. 
 
 PiQ. 13. — A capillary bloodvessel ; the two upper nuclei are 
 seen from their broad side, the two lower in profile. They all 
 show the network of fibrils. In the lower portion of the wall of 
 the vessel an imperfect network of fibrils may be perceived. 
 
 Pio. 14, a and b. — Two unstriped muscle-fibres. The intra- 
 nuclear network of fibrils is well seen ; these are in connection 
 with fibrils of the substance of the muscle-fibre ; there are seen 
 numerous transverse markings along almost the whole length of 
 the muscle-fibre. That these transverse markings correspond to 
 rings which constitute the cortical part, i. e., the sheath, is well 
 shown in a. 
 
 PiQ. 15. — A non-meduUated nerve-fibre of mesentery of newt ; 
 the nerve-fibre has a delicate sheath, the nuclei of which contain 
 a distinct network of fibrils. 
 
 Pig. 16. — A connective tissue corpuscle seen sideways. The 
 nucleus contains a network of fibrils, in connection with that of 
 the cell-substance. 
 
 Pigs. 17 and 18. — Two migratory cells ; 17, a common pale one, 
 18, a coarsely granular one. Their nuclei show the network of 
 fibrils very well. 
 
 Pig. 19. — A caecal dilatation of a Ij'mphatic vessel of the same 
 membrane, showing the nuclei of the endothelial cells forming 
 the wall of the lymphatic, and also nuclei of lymph-corpuscles. 
 
 Pig. 20, a and c. — Two connective tissue corpuscles ; the dis- 
 tinction between " ground-plate " and " fibrillar substance " is well 
 shown ; the " fibrillar substance " is in connection with the in- 
 tranuclear fibrils. 
 
 b, a nucleated plate ensheathing a minute non-medullated nerve- 
 fibre. The intranuclear network is seen in connection with the 
 pi:ocesses and fibrils of the connective tissue corpuscle c. 
 
:<.