peeeree decane? ye bewe’ vile bho pe areriee™ peowsen™ ooh (Let ot she eye int fever 2 wi Sete griviic pence oiwtst M i wv 7 - oi epeneden: viet Sivireries eden are nd 5h ee x A 4 werhevet (ee “e ee Ree lveer et oho shee eeuerae © sabe is rye ede ae Cd th ee Paes eof 99 e “he 28H Ske open pede teers pene tie pe! Seach oF Hope Here Yh bwiee > * be ene in zee peter abe Wah GOO HT hey ° “ ” eee eee h Sense Ferk tees ribs roe pr oeeeer ror hey a Sb vhebeteh Ss 6 (4 -PObeOHOis tt Gages jr ieh Het ers’ > oa aie sqs Fw wl et a ety peteeee othe 0 thew hs et Ot = - Sunuey Sate te “gr > te . oy C2 ay buen tedege der ete OHI be let Oe v 5) Ber dwdrde f aeHr todo eet more ~t oF gS . ; coled PPLE f LS | NN . an K 2./923 OLORIOA. y | yy inh ) ry, Ni a I (reer The Religion of Science Library. Vol. I. No. 6 Price, 25c Bi-Monthly MAY, 1894. Yearly $1.50 Entered at the Chicago Post Office as second class mail matter, rT ae THE PSYCHIC LIFE OF MICRO-ORGANISMS BY ALFRED BINET CHICAGO THE OPEN COURT PUBLISHING COMPANY 1894 HT 2 Rye a3 5 Hrom the Library of Professor Benjamin Breckinridge Warteld Beyueathed hy him to - the Library of Princeton Chenlnogiral Seminary QL18S THE PSYCHIC LIFE OF MICRO- ORGANISMS, Bae ORG one Sa UAC u 9 9 oe OF MICRO-ORGANISMS A STUDY IN EXPERIMENTAL PSYCHOLOGY BY ALFRED BINET AUTHORISED TRANSLATION CHICAGO THE OPEN COURT PUBLISHING COMPANY 1894. ‘TRANSLATION COPYRIGHTED BY THE OPEN CourT PUBLISHING Co. CHICAGO, ILL., 1888. PREFACE TO THE AMERICAN EDITION, I HAVE endeavored, in the following essay upon Micro-organ- isms, to show that psychological phenomena begin among the very lowest classes of beings; they are met with in every form of life from the simplest cellule to the most complicated organism. It is they that are the essential phenomena of life, inherent in all pro toplasm. We admit, accordingly, the Btencs of a vitalism, that is to say, of an aggregate of properties which properly pertain to living matter and which are never found in inanimate substances. Among these properties of life we classify psychological phenomena. Vitalism, it is unnecessary to say, has nothing in common with the doctrine upheld by the School of Montpellier. The principle here involved has nothing to do with properties and forces that are superadded to living matter; it concerns the properties that are in- herent in it—the properties that characterize life. The modern opponents of vitalism seek to confute the theory by attempting to explain all phenomena of life from physico-chem- ical forces. They maintain that according as physiology advances the tendency is to relegate all phenomena nominally physiological into the domain of physics and chemistry; and that it would be only a question of time, if as yet they had not succeeded in dem- onstrating that every vital process is founded upon mechanical phenomena. In a recent treatise upon ‘‘ Vitalism and Mechanism,’* M. Bunge, professor of physiology at Basel, has shown that the his- tory of physiology disproves these hypotheses. The more closely *G. Bunge, Vztalismmus und Mechanismus, Ein Vortrag, 1886. Iv. PREPACE: the phenomena of life are scrutinized, the more carefully they are studied in their various aspects, the more certain does the conclu- sion become that the processes attributed to physico-chemical forces in reality obey much more complicated laws. To illustrate, it was at one time conceded that the phenomena of resorption and nutri- tion were explainable by diffusion and endosmosis; Dutrochet, upon his discovery of endosmosis, imagined even that he had dis- covered the principle of life. At the present time we know that the walls of the intestines do not Sin any wise act like the inanimate membrane used in experiments in endosmosis. They are covered with epithelial cells, each of which is an organism endowed with a complex of properties. The protoplasm of these cells lays hold of food by an act of prehension, exactly as the ciliate Infusoria and other unicellular organisms do, that lead an independent life. In the intestines of cold-blooded animals the cells emit prolongations wnich seize the minute drops of fatty matter and, carrying them into the protoplasm of the cell, convey them thence into the chyli- factive ducts. There is still another mode of absorption of fatty matters, met with among cold-blooded as well as warm-blooded animals: the lymphatic cells pass out from the adenoid tissue which contains them, so that upon arriving at the surface of the intestines they seize the particles of fatty matter there present and, laden with their prey, make their way back to the lymphatics. Accordingly, the faculty of seizing food and of exercising a choice among foods of different kinds—a property essentially psy- chological—appertains to the anatomical elements of the tissues, just as it does to all unicellular beings, in the manner shown in our treatise. It is plainly impossible to explain these facts by the in- troduction of physico-chemical forces. They are the essential phe- nomena of life and are the exclusive appurtenance of living pro- toplasm. If the existence of psychological phenomena in lower organ- isms is denied, it will be necessary to assume that these phenom- ena can be superadded in the course of evolution, in proportion as : PREFACE. Vv an organism grows more perfect and complex. Nothing could be more inconsistent with the teachings of general physiology, which shows us that all vital phenomena are previously present in non- differentiated cells. Furthermore, it is interesting to note to what conclusion the admission would lead—as Romanes apparently does admit—that psychological properties are wanting in lower-class beings and that they enter at different stages of zodlogical development. Romanes has minutely particularized on a large chart the development of the intellectual powers, in quite an arbitrary manner. According to his scheme, only protoplasmic movements, and the property of excitability are present in lower-class organisms. Memory begins first with the echinoderms; the primary instincts with the larve of insects and the Annelids; the secondary instincts, with insects and spiders; reason, finally, commences with the higher Crustaceans. I do not hesitate to say that all this laborious classification is artificial in the extreme, and perfectly anomalous. All writers that have devoted themselves, with any pretension to special investigation, to the study of unicellular organisms, have attributed to these beings most of the psychological properties which M. Romanes reserves for this or that higher-class animal. This is the opinion of Gruber, of Verworn, of Mebius, of Balbiani, and of many other naturalists. Moebius recognizes that psycho- logical life begins with living protoplasm, and he considers it to be the highest aim of zodlogy to demonstrate the psychical unity of all animals. We could, if it were necessary, take every single one of the psychical faculties which M. Romanes reserves for animals more or less advanced on the zodlogical scale, and show that the greater part of these faculties belonged equally to Micro-organisms. But we must not unnecessarily extend the discussions of this introduc- tion. We shall accordingly limit ourselves to few illustrations. M. Romanes, in his zodlogical scale, assigns the first manifes- tations of surprise and fear to the larve of insects and to the An- VI PREFACE. nelids. We may reply upon this point, that there is not a single ciliate Infusory that cannot be frightened, and that does not mani- fest its fear by a rapid flight through the liquid of the preparation. If a drop of acetic acid be introduced beneath the glass-slide, in a preparation containing quantities of Infusoria, the latter will at once be seen to flee from all directions like a flock of frightened sheep. Memory, according to M. Romanes, first begins with the Echinoderms. Now, Mcebius, upon the occasion of a treatise upon the Folliculina ampulla,* a ciliated Infusory presenting complicated and interesting movements, properly remarks that every time an animal repeats the same action under influence of the same excita- tions, that fact proves that the animal is possessed of memory. In fact, memory is one of the most elementary of psychological facts. Lastly, the primary instincts, according to M. Romanes, begin first with the larvz of insects and with Annelids. We give, in con- tradiction of this statement, the recent observations of Verworn, +t which reveal the existence of curious instincts among the Rhizopods. The Diflugia urceolata, which inhabits a shell formed of particles of sand, emits long pseudopodia which search at the bottom of the water for the materials necessary to construct a new case for the filial organism to which it gives birth by division. *The pseudopod, after having touched a particle of sand, contracts, and the grain of sand, adhering to the pseudopod, is seen to pass into the body of the animal.. Verworn, instead of grains of sand, placed small fragments of colored glass about the animal; some time afterwards, he noticed a heap of these fragments on the bot- tom of the shell. He then saw a bunch of protoplasm issue from the shell, representing the new Diffugia produced by division. Thereupon, the materials collected by the mother-organism—the fragments of colored glass—came forth from the shell and envel- oped the body of the new individual in a sheath similar to that en- * Moebius, Das Flaschenthierchen, Folliculina ampulla, 1887. t+ Verworn, Zeztschrift fiir Wissenschaftliche Zoologie, Bd. 46. H. 4. 1888. PREFACE. : VII casing the mother. These fragments of glass, loosely interjoined at first, were now cemented together by a substance secreted by the body of the animal. Two facts are to be remarked in this observation: first, the act whereby the Difugia collects the materials for providing the young individual with acase, is an act of preadaptation to an end not present, but remote; this act, therefore, has all the marks of an instinct. Further, the instinct of the Diffugia exhibits great pre- cision; for the Difiugia not only knows how to distinguish, at the bottom of the water, the materials available for its purpose, but it takes only the quantity of material necessary to enable the young individual to acquire a well-built case; there is never an excess. It is interesting to note that the Difflugia does not act differ- ently from animals possessing more highly complicated organiza- tions and endowed with differentiated nervous systems, as for in- stance, the larvze of Phryganids which form their sheaths from shells, grains of sand, or minute slivers. We shall not regard it as strange, perhaps, to find so complete a psychology in the history of lower organisms, when we call to mind that, agreeably to the ideas of evolution now accepted, a higher animal is nothing morethana colony of protozoans. Every one of the cells composing such an animal, has retained its primitive proper- ties, giving them a higher degree of perfection by division of labor _and by selection. The epithelial cells that secrete the nails and the hair are organisms perfected with reference to the secretion of protective parts. Similarly, the cells of the brain are organisms that have been perfected with reference to psychical attributes. € Paris, November 20, 1888. ALFRED BINET. TABLE OF CONTENTS. INTRODUCTORY. A branch of Comparative Psychology little known.—Defini- tion of Micro-organisms. — Their classification.— Main groups of animal Micro-organisms.—Complexity of their life of relation.—The Micro-organism not simply an irrita- tablet cellular Hin ys. akigy bala eek istee «onl peigiae haat ae THE MOTORY ORGANS AND THE ORGANS OF SENSE. MOTORY ORGANS. Motility.—The pseudopod.— Opinion of M. Rouget relative to the formation of pseudopods.—The vibratile cilia.— Their morphological significance.—Observations of Engel- mann.—The movements of the vibratile cilia are subject to the will of the animal.—Observations of M. Balbiani upon the Didinium nasutum.—Experiments of Rossbach. —The flagellum.— Diversity of its movements.—Observa- tion of Biitschli upon the flagellum of the Glenodinium cinctum.—Metabolic infusoria.—The granulous bands and bright filaments.—The contractile vesicle.—The move- ments of Bacteria and Gregarine&... ei... ied. cede ence THE NERVOUS SYSTEM. Absence of a central nervous system in single-celled organ- isms.—Hypothesis of a diffused nervous system.—Obser- vation of Gruber upon the Stentor in process of division. THE ORGANS OF SENSE. Organs of touch.—Organs of sight.—Ocular spot in Flag- ellates.—Ocular spot of vegetable zodspores.—Experi- ments of Klebs upon the structure of these spots.—The Pages 4-20 20-22 CONTENTS. ? IX Pages hematochrome is not without analogy to the chlorophyl pigment.—Opinion of naturalists upon the physiological function of the so-called ocular spots.—Observation of M. Pouchet upon the eye of the Glenodinium polyphemus. — This eye is composed of a pigmentary mass and of a refringent body.—Observations of M. Kiinstler upon the eye of /Phacus.—Observation of Claparéde and Lach- mann.—Observation of Lieberkiihn.—Sensitiveness of the Euglena to light.—Experiments of Engelmann.—The vesi- cles of Miiller in the Loxodes rostrum... ...cc cece eee ees 22-31 ads NUTRITION. Psychical phenomena connected with respiration.—Search for oxygen by the bacteria of putrefied matter.--Observa- ROMO MEETS ATI oe 4. ghia eee spake et 5S ee cierto wie 31-34 BL THE PSYCHOLOGY OF NUTRITION. Psychical phenomena connected with nutrition.—Vegetable, or holophytic, nutrition.—-The chromatophores. -—Structure ot the chromatophores.—Coincidence between the presence of an eye and that of chlorophyl pigment.—Comparison between the Luglena and the Peranema.—Nutrition by endosmosis, or saprophytic.—Animal nutrition, choice of nutriment.—-Prehension of foods by the Ameeba, the Actin- ophrys, the Monas, the Acineta.—Opinion of M. Mau- pas upon choice by preference.—Capture of food.—The vorticel Ciliates.--The Hunter Ciliates. —The Amphileptus. —The Didinium nasutum,—Movements of defense and DG eee ote ee ats hh cing Fhe ee ta eee velar e wee 34-55 IV. COLONIES OF UNICELLULAR ORGANISMS. Colonies of unicellular organisms.—Colonies of single-celled organisms have their origin in the segmentations of a mother-cellule.— Temporary colonies which are formed beneath the cuticle.--The Gonium.—The Eudoryna.--The x CONDENS: 4 Pages Volvox.—Difference between a pluricellular organism and a colony of unicellular organisms.—Voluntary combina- tions: —— Che ‘Bodo cad aus, Qua ic chee ee ne ee eee 55-61 THE PSYCHOLOGY OF PROTO-ORGANISMS. Remarks upon the psychology of Micro-organisms.—Their various actions are direct responses to stimuli from the out- ward world.—Perception of external bodies.—Choice.— Calculation of the positions occupied by external bodies. —Movements of Micro-organisms..... Re Betton ee a 61-65 VI. FECUNDATION. Fecundation among Infusoria.—Historical.—Psychological preliminaries of fecundation-—Observations of M. Bal- biani upon the Paramecia, the Spirostomes, and the Sten- tors.—Copulation.—Fecundation among the Vorticels.—— Observation of Engelmann. —Material phenomena in fec- undation.—The rdédle of the nucleus, and the réle of the nucleolus.—Description of the phenomena as seen in the Chilodon cucullulus (see appendix), the Paramecium bursa- via and inthe Paramecium aurelia.—Observation of M. Balbiani upon Parameecia, of which the nucleus is overrun with parasites... .4 isis Os sip mics Reyne ete smote Te eee 65-75 VIl. FECUNDATION IN HIGHER ANIMALS AND PLANTS. Fecundation in higher animals and plants.—The spermato- zoid and the ovule can be compared to Micro-organisms,— The elements can live for a certain time independent of the animals from which they come.—Their motor organs. —The movements of the spermatozoid towards the ovule. —Length of road to’ be traveled.—Obstacles to be over- come.—-Windings and intricacies of the path.—The sper- matozoid of the silk-worm.—Arrival of the spermatozoid in contact with the ovule.—QObservation of Fol upon the fecundation of the star-fish.--The cone of attraction.— CONTENTS. Sexual selection operating as between different spermato- zoids.—Movements of the female element.—-Vegetable fecundation.—Progressive differentiation of the two sex- ual elements.—-Sexual reproduction of the £ctocarpus stli- culosus, after Berthold.—-Investigations of Pfeffer upon the spermatozoids of cryptogams.—Action of certain chemical excitants upon these elements.—-Specific charac- ter of the excitant.—The threshold of excitation.--Appli- ERO LANV OEE S LAWS visio ph om tha a de acelaved VAC Rt zntee gaa owas VELL THE PHYSIOLOGICAL FUNCTION OF THE NUCLEUS. Functions attributed to the protoplasm and to the envelop- ing membrane.—The nucleus, its histological importance proved by the phenomena of caryokinesis.—Balbiani and Gruber have, at times, observed Infusoria and Actinophrys deprived of nuclear substance.-—Nussbaum's and Gruber’s experiments of vivisection upon the Svfentor ceruleus.— Fragments provided with nucleus reconstruct themselves. —Experiments of Balbiani —Facts observed by Gruber, in general, confirmed.—Error of Gruber respecting frag- ments without nucleus.—These fragments do not con- tinue to live, their plasma undergoes disorganization. —Experiments of division. — Experiments made upon Infusoria while in conjugation.—The presence of the old nucleus in a severed fragment only brings about an incomplete regeneration.—The nucleus presides over all physiological functions, the totality of which con- stitutes life. —The regenerative and reproductive property of the plasma is lost before the psychical functions are.— Agreement of all these facts with the phenomena ob- served as taking place during the spontaneous division of ISO OES ATI SIS aris hn a as. Bese Meee oa weak FF we ee Smee IX, CONCLUSION. Statement of M. Richet’s position respecting cellular psy- chology ....... Mth Aes hte ite fe eee Rae ale Ts XI Pages 7579! XII COM LLL £55 Aes Pages Romanes’s conception of the psychic activity of Proto- OY PANISTIS secre. SM wa cove wher ea ga aion el hae en eee 105 Irritability and -cellular_psychology. owes eee ee ee 107-110 Correspondence between Ch. Richet and Alfred Binet, ap- pearing in the Revue Philosophique of February, 1888, re- printed from THE OpeN Court of December 27, 1888.110-115 APPENDIX. Additional cuts illustrative of : The Conjugation of the Paramecium aurelia............ 1i6 The Conjugation of the Stentor ceruleus...........0.. 116 The Copulation of the Stylonichta myttlus.... 0.060.060. 116 The Conjugation of the Carchesitum polypinum.......... ity The Conjugation of the Chilodon cucullulus (with explana-- tiong) ssc ee ee srenatehea ona D ee abi e ake es cine eee 118 Addenda. Notes and References omitted in the text...... I2I THE PSYCHIC LIFE OF MICRO-ORGANISMS. THE study of microscopic organisms has hitherto been somewhat neglected by students of comparative psychology. Naturalists who have devoted their at- tention to the study of these beings, have collected a great number of interesting facts concerning their psychic life; but these facts have not yet been critically examined and collated; they are scattered in reports and publications of all kinds, where the psychologist never dreams of looking for them. We shall endeavor to make him acquainted with a part of this wealth. Under the name Micro-organism are included all those beings which by reason of their extreme smallness and simplicity of structure represent the lowest stages of animal or vegetable life; they constitute the very sim- plest forms of living matter, and consist of a single cell. Some inhabit fresh and salt waters, serving as food for a great many other organisms, or contributing by means of their calcareous or silicious skeletons to the formation of continents. Others live as parasites in the organs of animals and plants, and induce more or less serious disorders in the constitutions of the organ- isms they have penetrated. Others, again, acting like ferments produce important chemical modifications in organic matter in the course of decomposition. A great number of classifications for the methodical distribution of these beings has been proposed; but not one of them is altogether satisfactory; and that F LILLE SMELL Grane ee stands to reason. Ifa natural classification is always a complex piece of work in the case of the higher ani- mals which differ from each other in important features and between which a comparison can be instituted, the difficulty attending the classification of simple or- ganisms which present only the slightest differentia- tions is still more difficult. The principal division made is that which divides them into animal Micro-organisms or Protozoans and vegetable Micro-organisms or Microphytes. The line of demarcation between these two king- doms is far from being well defined; there are a great number of micro-organisms ¢zcerte@ sedis, which bota- nists usually place in the vegetable kingdom, but which zodlogists prefer to classify as belonging to the ani- mal kingdom.* We give below a list of the most important groups of animal micro-organisms. ANIMAL MICRO-ORGANISMS. INFUSORIA. | MASTIGOPHORES. SARCODINES. SPOROZOA. Ciliates Flagellates. Rhizopods, Gregarinida. Suctoria (Suckers) Choanoflagellates. Heliozoa. Coccidia. BAe anes Saar tee pen Pee Dinoflagellates. Radiolarians, - Sarcosporidia. fea ieee Wee whee Cystoflagellates. web. cbc. aa ye0sporiatae Soil PAL hk PATE Re ike NE A a eine Ure Sioned. Mierosponraia We propose, now, to study the psychic life of these lower organisms, or, to speak in more general terms, their life of relation. Itis well known that the expres- sion, the life of relation, comprehends essentially two dis- tinct ideas: first, the action of the external world felt by the organism: or sensibility; secondly, the reac- tion of the organism on the external world: or move- * The best mark to distinguish the two kingdoms is the chemical nature of the enveloping membrane: in the case of vegetable organisms, the enveloping membrane is made up of a ternary substance, cellulose; while in animal organ- isms it is albuminoid in character. OF MICRO-ORGANISMS. 3 ment. It is customary to apply to the union of these two properties the name irritability, which expresses the reaction of the micro-organism upon exterior forces. It is therefore held, and with reason, that every living cell is irritable, that is to say that it pos- sesses the property of responding by movements to the excitations which it suffers. In admitting then that irritability is the founda- tion of the life of relation, and consequently also the foundation of psychology, we must nevertheless guard against comparing the autonomous cell of micro- organisms to a simple irritable cell. Although the body of these small beings may be equivalent to a simple cell, it would be an error to believe that their life of relation consists in a motory reaction consequent upon exterior irritation. At the close of our investiga- tions into the psychology of Proto-organisms we shall see that, in these inferior beings which represent the simplest forms of life, we find manifestations of an in- telligence which greatly transcends the phenomena of ‘cellular irritability. Thus, even on the very lowest rounds of the ladder of life, psychic manifestations are very much more complex than is usually believed, and the conception of cellular psychology which some very recent authors have formed, seems to me a very crude analysis of the most delicate of phenomena. In the great majority of pluricellular animals, the life of relation is exhibited in a nervous system and ina muscular system. In Micro-organisms the same cannot be said to be the case: the greater part possess neither a central nervous system nor organs of sense; some even lack organs of locomotion. The functions of the life of relation are performed by the entire mass of the body: many of the Protista, for example, ch THLE PSYCH OAL: have not a trace of an anatomically differentiated visual organ; it is the entire protoplasm of the ele- mentary organism that is excitable by light, as it is also by heat or by electricity. In other Micro-organ- isms somewhat higher in the scale, a beginning of differentiation may be seen to make its appearance, giving birth either to some vreau of sense or to some organ of locomotion. We shall give a general description of these organs. The study of this first move in the work of differentia- tion is of great interest to comparative anatomy and physiology; no less interesting is it to psychology. Besides dwelling on these preliminaries of our work, we shall have occasion to note new and interesting facts, rE: THE MOTORY ORGANS AND THE ORGANS OF SENSE. Motility. From the schedule of the groups of ani- mal micro-organisms which we have given, it will be seen that they are subdivided into four classes, the Infusoria, the Mastigophores, the Sarcodines and the Sporozoa.. The distinction between these classes depends on the existence and the nature of the motor organs. The Infusoria comprise the protozoa that move by the aid of vibratile cilia distributed in greater or less number over their body. The second class, the Mastigophores, re those animals which move by the aid of flagella, that is to say by the help of long filaments. The third class, the Sarcodines, comprises those animals which move by the aid of pseudopodia; which are projections of the substance of their, bodies. The fourth class, the Sporozoa, is characterized by OF MICRO-ORGANISMS. 5 the mode of multiplication: they are reproduced by spores. In the animals of this group, the special motor organs are wanting; these creatures therefore generally move very little, or they present only move- ments of which the principles are unknown. We shall successively describe the pseudopodia, the vibratile cilia and the flagellum. The Pseudopod. -The formation of pseudopodia takes place chiefly in naked cells—in cells lacking an enveloping. membrane, in the Sarcodines in general. They can easily be studied in the Amwba princeps, a microscopic animal which is found in abundance in fresh water containing organic matter in a state of putrefaction. It has the aspect of a small gelatinous mass, irregular, formed of a colorless substance, the protoplasm. The chemical nature of protoplasm is still very imperfectly understood; it is only known that it is the result of a mixture of albuminoid mat- ters, with an addition of water and mineral elements. In the protoplasm of the amceba exists a small rounded _and refracting mass, containing one or two bright cor- puscles in its interior; this small mass is called the nucleus, and the corpuscles the nucleoli. The form of the body of the amceba is rendered very irregular by the fact that certain parts of the mass lengthen, and form short and rounded protuber- ances which are designated by the name of pseudo- podia. It is by means of these pseudopodia that the animal moves; it emits them in the direction in which it is going, then it retracts them, while other parts of the mass are in their turn elongated. The whole body moves by creeping. The amceba in moving has the aspect of a drop of oil moving along. To explain the mechanism of this movement, it must be supposed 6 LAE? ESCH G aL Lae, that the extended pseudopod seizes some point of sup- port with its free end, then, in contracting, draws the entire mass of the body up to this. But it is difficult to understand what the cause of the elongation of the pseudopodia is. It has been supposed that the pro- toplasm is endowed with great elasticity and that the elongation is the return of this substance to its primi- tive form. That is not the explanation given by M. Rouget. The learned professor of the Museum has been kind enough to write out the following note for us, in which he recapitulates his opinion: “Every time that a protoplasmic organism dies, or is subjected either to a strong electric excitation, or to a relatively high temperature (+ 45° to + 50°),the pseudopodia are retracted and re-enter into the mass, which assumes a globular form; the same is the case in the protoplasm of vegetable cells, the inter-cellular reticulum of which breaks in receding, or else the mass of protoplasm divides into spherical bodies. These states of retraction are the analogues of muscular rigidity, and like it represent the condition of maximum contraction in the protoplasm—nevertheless the style © of the Vorticels (Carchestum) which is a protoplas- mic formation, under the same conditions, remains in a state of permanent retraction. It follows from this that the emission of the pseudopodia, ¢hetr elongation, cannot in any case be considered as a direct act of the contractility of the protoplasm. 7 “The production of the pseudopodia, one of the most difficult problems, cannot, in my opinion, be ex- plained, except in the following manner: All proto- plasmic masses, and especially the amceba, consist of two parts, an enveloping membrane or ectosare, vis- OF MICRO-ORGANISMS. 7 cous and elastic, and the central liquid contents hold- ing granules in suspension. “From the time of the apparition of a pseudopod, a current of liquid is visible which penetrates into the pseudopod and which seems to contribute to its elon- gation. It is very evident that the liquid is passive, that it penetrates into the pseudopod only because, pressed upon from all sides, it finds less resistance there. I think that the (in appearance) homogeneous _hyaline substance of the pseudopod is also a species of hernia of the estosarc, resulting from a diminution of the elastic resistance at the point where it appears, with an increase of elasticity or of contractility (to me two modalities of the same property) in those parts of the ectosarc where pseudopodia are not produced. When the contractility or the elastic tension of these parts diminishes, and returns to its original state the pseudopod re-enters into the mass. Add to this that, in an amceba of large dimensions, Ameba ferrt- cola, it has seemed to me that the most external mem- brane of the ectosarc showed striwof a granular ap- pearance which may be identical with the strizor con- tractile fibrils of the ectosarc of the ciliated infusoria, Stentor, Spirostomes, Bursaria, etc.” (May 20, 1887.) The pseudopod does not represent a permanent, differentiated organ of locomotion; it is produced bya simple prolongation of the mass of the body, which can take place at any point whatever, and when the act of locomotion has been accomplished, this pro- longation re-enters into the common mass. without leaving any traces of its emission. In other animal species, for example the Pefalobus of Lachmann, initial traces of differentiation of the pseudopodia have been observed; they always form at the same 8 THE PSV CHIGALLLLE point of the body, on a level with the anterior part; but, in spite of this constant localization, the motor organ has only a transitory existence; it is produced at the moment it is needed, and disappears into the mass of the body, when the movement has been exe- cuted. In the Actinophrys there is a still greater pro- gress: the numerous pseudopodia emitted by this ani- mal, and which have the form of filaments, are perma- nent organs with definite functions. The Vtbratile Cilia. The vibratile cilia are short, extremely thin, homogeneous filaments which are agi- tated by a vibratory movement. These are distinctly differentiated organs of locomotion. They have, moreover, several functions: firstly, they enable the animal to move about in the liquid; secondly, they serve it as an organ of prehension; thirdly, they per- mit a renewal of the water which furnishes the neces- sary air for respiration to the animal; perhaps they also serve as organs of touch. The vibratile cilia lend to the Infusoria their peculiar character and enable them to be distinguished from all the other Protozoa. Cilia are also found in’ vegetable species when young, and in the larve of Coelenterates, of mollusks and of worms. But among the Protozoa, it is the Infusoria alone that are ciliated. The cilia are distributed in various manners, differing according to the species. In the holotricha, they are distributed regularly over the whole surface of the body, and almost all have the same length; in the Heterotricha, they also cover the whole surface of the body, but they are unequal in length. To this group belong the Szentors which have long cilia in- serted around a circular surface, extending almost to the mouth. This surface is a rotatory organ, analo- OF MICRO-ORGANISMS. 9 gous to that of the rotifers; it produces eddies in the water and thus causes the flow of foreign bodies to the mouth: these animals have the- rest of their bodies covered with fine cilia. In the Ayfotricha the cilia are located on the ventral surface of the body and aid in locomotion. In the Peritricha, they form a cir- cular or spiral row on the anterior part of the body, and lead tothe mouth. This is observed in the Vor- ticels, sessile species which have no other cilia than those which are used for the prehension of food; the rest of the body is bare. Much has been said about the morphological signif- icance of vibratile cilia; several micrographists have held that the cilia are attached to the enveloping mem- brane only, and have no connection whatever with the protoplasm. That was notably the opinion of Robin; itis entirely wrong. ‘The cilia are never simple pro- longations of the cuticle; they have their root in the protoplasmic substance; they pass through orifices in the cuticle, which consequently is pierced by a multi- tude of small holes. Engelmann, in recent observa- tions, has been able to trace the extremity of the vibra- tile cilia into the interior of the protoplasm; he made this observation on the marginal cilia of the Stylo- nichia; from each of these threads he has seen sep- arate a pale fibre, which moves along almost directly beneath the cuticle in a direction perpendicular to the lateral edge of the body; towards the median line of the ventral face the fibres are often laid bare, because the body of this Infusory voids its protoplasmic sub- stance; there the fibres have the aspect of. tightened threads. Engelmann sees in this observation a con- firmation of the opinion that the bodies of infusoria are formed of one single cell, because, according to IO LHE PSV CHLC-LLILE other observers, there exist also in vibratile cellules filiform striz which seems to be a continuation of the . cilia, and which traverse the protoplasm of the cell throughout its whole length. We might add to this direct observation several other facts showing that the vibratile cilia are indeed prolongations of the plasm. Under the action of re-agents the cilia act like the cellular protoplasm; they are coagulated by the acids and dissolved by weak alkalies,-while the cuticle offers a greater resis- tance to these same agents. These vibratile appendices are not without analogy with the pseudopodia of naked cells; Dujardin, a French naturalist, demonstrated this in 1835, although efforts have since been made to bestow the honor of this discovery upon the Germans. Dujardin has proved that the amceboid movement and the ciliary movement are only two manifestations of the con- tractile power of protoplasm. In fact, if instead of examining a pseudopod with lobed outline hke that of the amceba, we observe the slender and flamentous pseudopodia of the Foramenifera, we see that the ex- | tremity of the filament is agitated by the same vibra- tory movement as the vibratile cilium. All the transitions from the fine and delicate cilia to the large cilia, tapering in form like a stilleto, which have been called cirri, have been observed; moreover these cirri are formed of agglutinated cilia; by the aid of certain re-agents they have been dissociated: An observation of a ciliated infusory, the Didinium nmasutum (see the illustration further on) made by M. Balbiani, shows that the movement of the cirri is not an involuntary movement like that of the cilia of the vibratile epithelium, with which it has often been OF MICRO-ORGANISMS. II compared, but that it is completely under the control of the will of the animal, like the organs of locomotion of animals much higher in point of organization. “The Didinium has two rows of equal, and rather strong, vibratile cilia, disposed transversely around the body, in the form of two belts or crowns. The rest of the body of this animal is entirely stripped of cilia, but its double vibratory belt suffices to enable it to execute the most rapid and most varied evolutions in the water. Not only does it swim forwards and backwards with perfect ease, but the progression in both directions is always accompanied bya rapid rota- tory movementof the animal aboutits longitudinal axis, similar to that observed in other infusoria that have a cylindrical body. The two rows of cilia always act in union during the locomotion, and the direction which the animal gives to them, determines the direction in which it wishes to move. In the movement for- Fig. 2.—Didiniunt na- sutune (Balbiani). Out- line of movement back- wards. The cilia are Fig. 1.—Didinium na- sutum (Balbiani) Fig- ure representing move- ment forward.The cilia Fig. 3.—Didiniunt na- sutunt (Balbiani). A sketch of rotatory movement in one spot. are all turned towards the front part of the body. all turned towards the back part of the body. The cilia of the ante- rior belt are directed forwards, while those of the posterior belt are directed backwards wards, all the cilia are directed toward the an- terior part of the body (fig. 1); when it swims backwards, they are reversed (fig. 2). The in- fusory thus rapidly makes its way across the field of vision by jerks; from time to time it suddenly stops, all the time continuing to turn around rapidly on its 12 TELL PSY CALC eh LICE axis on the one spot, during which movement the cili- ated belts beat the water in opposite directions, the anterior ones being turned forwards, while the posterior are turned backwards (fig. 3). The result of this is that the effects of these small locomotive apparatuses neutralize each other in the same manner as two heli- ces acting in opposite directions, and that the animal remains stationary, while all the time turning rapidly about itself, sometimes horizontally, sometimes verti- cally on its conical appendage, just as on a pivot.” Certain Infusoria, for example the Condylostoma patens, which has been thoroughly studied by M. Maupas, possess at the same time the two kinds of appendages, the cilia and the cirri. The former, which cover the dorsal surface of the animal, are fine, very dense and animated by a rapid and unceasing vibra- tile movement. The cirri, which cover the ventral surface are placed apart; furthermore they do not vi- brate rapidly; their movements are slow, and when the infusory moves, one can see them move success- ively on the plate of glass and support themselves there, in the manner of a foot, to make the body ad- vance. When the animal stands still, the cirri are ab- solutely immobile, while the cilia continue their vibra- tile movement. This observation which can equally well be made of the Oxytrichid, shows that the vibra- tile cilia are the organs of involuntary movement, and | that the cirri are more directly subject to the will. The fact is demonstrated by the experiments of Ross- bach, who observed that, under the influence of the falling of the temperature (from + 15 to + 4) or of the rising of the temperature (from + 35 to + 40) or under the influence of various chemical substances, the large cilia, the organs of voluntary movement,are OF MICRO-ORGANISMS. 13 paralysed, while the fine and delicate cilia continue their movements, which do not seem to be under the influence of the will. These movements alone cause the whole body to rotate until the vibratile cilia are in their turn paralyzed. Besides the cilia and the cirri, other appendages in the form of membranes are found among the Infu- soria, appendages which are attached to the anterior part of the body or the peristome; these membranes serve the purpose of causing eddies in the water, which bring the floating alimentary particles into the mouth. They are modifications of the vibratile cilia; these membranes like the cirri are formed of aggluti- nated cilia. The Flagellum. The study of the third organ of lo- comotion, the flagellum, brings us to speak of the class of Mastigophores and more particularly of the group Flagellata. The Flagellates are Protozoa of very small size, all in all, very much smaller than the ciliated Infusoria. They have no vibratile cilia at all, but -they are always equipped with one or more fila- mentous appendages which have the form of a long lash. This is the flagellum. This lash, like all the organs of locomotion hitherto studied, has two func- tions: it is at once an organ of locomotion and an organ of prehension. The flagellum is most fre- quently single or double (see fig. 4, representing the Luglenadeses with its single flagellum); sometimes a person can count a much larger number of them, four, six, eight, ten, and more. As regards the insertion, the same variations are met with. Sometimes the flagella are very numerous and seem to be planted on the same point of the surface of the body, thus forming a brush or plume. In other species we find several 14 THECPSYVCHILCALLLE flagella arising in the anterior extremity of the body, directed forwards, and also posterior or caudal fila- ments which are turned toward the rear. This is observed in the genus 77¢chomonas,; the anterior fla- gella serve for purposes of locomotion, perhaps also for the prehension of food; the posterior flagella, on the contrary, are solely organs of loco- motion; they resemble a trailing tail and perform the functions of a rudder. In passing we may point out the great morphological resemblance be- tween the Flagellata and the sperma- tozoa of animals, the antherozoa and the zodspores of plants. The organs of propulsion in these beings are the same. The Protozoan with its flagellum executes the most varied movements, moving first in one direction, then in another, and in different planes; some- times the animal curves about entirely; but most frequently, when he uses it as an organ of prehension, he extends it its whole length before himself; the basilar part remains completely immov- Fig. 4. able and rigid, while the free end alone Euglenadeses, f F +c. = contractile re. CxeCUteS Movements destined to drive servoir; o. — eye; # food to the mouth, which is generally = disk of the para- — mylone; ck. — chro- situated at the base of the flagellum. matophores; 7. = nu- cleus. ‘Ehrenberg gives to the flagellum the name proboscis; its peculiar mobility renders it worthy of thisname. The flagellum, like the vibratile cilium, is an expansion of the protoplasm through the envel- oping membrane. M. Certes has observed a Proto- OL MICRO-ORGANISMS. 15 zoan, the flagellum of which between whiles re-entered into the mass of the body, with which it mingled;it was replaced by a pseudopod which soon attenuated and took the form of a flagellum. Bitschli has recently made a very interesting ob- servaticn on this organ of locomotion. Under certain circumstances, the Peridinia (Dinoflagellates) throw off their long flagellum and enter into a state of repose; they generate them quite as easily. In the Glenodin- zum cinctum, Biitschli has seen the flagellum roll itself up first like a cork-screw, and then suddenly detach itself from the animal; having become free, it stirs about in the water for several minutes before becom- ing motionless. ‘This observation enables us to refute those naturalists who believe that, the vibratile cilium is an appendage of the cuticle, by bringing forward the fact that when the cilia with the portion of the cu- ticle in which they are inserted are separated from the cell, the cilia continue to move; we have just seen that the flagellum moves even after it is separated from the cuticle; this persistence of movement is sufficiently explained by the protoplasmic nature of the cilia and of the flagellum. From another point of view, the observation of Bitschh gives us a curious example of the phe- nomena of autotomy, which have recently been studied by Frédéricq. The pseudopodia, the vibratile cilia, and the flagel- lum, constitute the three motor organs that are most frequently found in the kingdom of the Protista. Among the Infusoria, moreover, particular differentia- tions of- the protoplasm have been described, which may be compared to the muscular fibres of the higher animals. The Vorticellaz are supported by contractile 16 | ATER PSV CHIC DERE peduncles. These are filaments capable of rolling themselves up into the form of a cork-screw, when the animal is disturbed. Certain Infusoria can modify the form of their body by a sudden contraction: they have been called metabolic; such are the Stentors, the Prorodons, the Spirostomes. In contradistinction, those which do not change their form, for example the Paramecia, have been called ametabolic. Accord- ing to the observations of Lieberkithn, which date back to 1857, the metabolic Infusoria have their bodies divided into large granulous bands, separated by bright filaments. It has been asked which is the contractile element: is it the band, or is it the fila- ment? Oscar Schmidt, Kélliker, Stein, and Rouget think that it is the band which is the contractile ele- ment. This opinion is based on the following fact, which M. Rouget was the first to observe: at the mo- ment at which the animal contracts, the band presents transverse striae; this appearance is due to the fact that the bands contain in the state of rest small gran- ules which, during the contraction of the animal, are disposed in transverse series, so as to recall the sax- cous elements of Bowman. : Lieberktthn, Greef, and Engelmann attribute the active part to the bright fibre. Engelmann has based his opinion on the fact that he recognized in the filament the property of double refraction, which, according to him, belongs to all contractile substances, while the substance which separates the filaments shows only single refraction. However that may be, it is one of these two ele- ments that possesses the power of contraction, and which deserves the name of myophane, which Haeckel gave it. It is very remarkable that in the Stentors OF MICRO-ORGANISMS. 17 and the Spirostomes the fibrillous striz are in intimate connection with the basilar extremity of the vibratile cilia. In the Vorticellz one can clearly see the fibrils converge toward the axis of the style, the contractile element of which they constitute. We shall not leave the study of the motor organs without saying a word about the rhythmical movements which can be seen in the contractile vesicle of the Micro-organisms, vegetable as well as animal. This’ vesicle is a small cavity which is dug into the proto- plasm, and which alternately increases and diminishes its capacity. Scientists byno means agree as to its ex- act function; Biitschli and Stein consider it to bea secretive apparatus. Its pulsations are very regular. Their number is constant in every species. In the chilodon cucullulus, a pulsation occurs every two sec- onds; in the Crytochium nigricans, every three sec- onds; in the Vorticelle, every eight seconds; in the _ ELuplotes, every twenty-eight seconds; in the Acitnerza wncurvata, every six minutes; Rossbach, whose curi- ous experiments with the vibratile cilia and the cirri we have already cited, has made analogous experi- ments with the contractile vesicles. He observed es- pecially that, under the action of alkaloids, the con- tractile vesicle ceased pulsating in diastole, and di- lated enormously; but poisonous agents do not act all at once on the movements of the vesicle; they begin by paralyzing the larger cilia, which are under the in- fluence of the will. The movements of the vesicle, like those of the small cilia, persist for a much longer time. M.E.Maupas has seen Paramecia, killed by a discharge of trichocysts, become completely immo- bile, with their vibratile cilia inert and rigid, while the contractile vesicle continued to pulsate 18 THE PSVCHICRL LIE, with the same activity; this activity continued for an hour. We have now briefly examined the morphology of the motor organs of Micro-organisms. It is very difficult to determine the physiological process of the movements produced by these organs. The simplest movements and the ones most easily un- derstood, are those by which a cell suddenly and strongly irritated withdraws its prolongations and as- sumes a spherical form; this change of form can be explained by a quick condensation of the protoplasm, which becomes the seat of a phenomenon similar to that of a contracting muscle. The sudden modifi- cations which are observed to take place in the form of the so-called metabolic Infusoria are in this way explained by an analogous phenomenon, so much the more evident as the Infusoria which possess this prop- erty, show in the cortical layer of their protoplasm (ectosarc) granulous bands which have with more or less justice been compared to the muscles of the higher animals. The displacements of the body de- termined by the pseudopodia, by the vibratile cilia, and by the flagellum are much more difficult to inter- pret; meanwhile it is probable that the movement proceeds from the contractions of the protoplasm which are produced either in the ectosarc or in the motor organ itself; the latter is automobile, as is seen, for example, when a flagellum separated from the rest of the body continues to move in the liquid. It is well known that any number of discussions have been raised as to the manner in which the ped- icel on which the Vorticelle are mounted, contracts. Still more obscure is the oscillatory movement of the. Bacteria. These small beings are very mobile when OF MICRO-ORGANISMS. 19 chey find themselves ina liquid; they frequently ex- hibit a movement of oscillation which sometimes car- ries them forward, sometimes backwards. An attempt has been made to explain these movements by postu- lating the presence of organs of locomotion, extremely slender filaments planted at one of the extremities of the Bacteria like small rods; but the existence of these organs has not been absolutely proved. Even more obscure is the movement observed in certain Grega- rines. It would seem that in the case of these ani- mals, which are often of considerable size, one ought to be able to understand the principle of their move- ments much more easily than in the case of such small beings as the Bacteria; but this is not the case. The Polycystids have a very peculiar manner of mov- ing; the motion is one of perfect translation, uniform and rectilinear; the animal seems to slide all of a piece over the object-plate; it can go to the right, to the left, stay its motion and resume it again; it is free in directing its movements. Now, during this move- ment nothing can be seen to take place in the body from within or without. An analogous phenomenon is to be observed in the Diatomes. Some scientists have wished to explain the mysterious motion by translation executed by the Gregarines, as being due - to an imperceptible undulation of the sarcode; but if there were any undulations whatever, one ought to ob- serve a correlative movement in the granules inside; now this is something that is never seen. Thus there still exists a great deal of obscurity concerning the principles determining motion among the Proto-organisms. The theories based upon muscular contraction that have been propounded from observ- ing higher animals, are by no means sufficient to ex- 20 EB 9 Mines Ea A Ce KERIO: plain the phenomena of motility among certain Pro- tozoa and Protophytes. Nervous System. WHitherto not the minutest trace of a central nervous system has been found in a single Proto-organism. The nervous function among these inferior beings devolves upon the protoplasm, which is irritable, which feels and which moves, and which, in certain species, as we shall see later on, is even ca- pable of performing certain psychic acts, the com- plexity of which seems quite out of proportion to the small quantity of ponderable matter which serves as a substratum to these phenomena. There is, more- over, no occasion to be surprised that an undifferen- tiated mass of protoplasm should be able to exercise the functions of a veritable nervous system. In fact every nervous element is nothing else than the pro- duct of protoplasmic differentiation; the protoplasm embodies in itself all the functions that, in conse- quence of an ulterior division of labor among the pluricellular organisms, have been assigned to distinct elements. It has rightly been held, therefore, that if no nerv- ous system, anatomically differentiated, existed in proto-organisms, it must be admitted that their pro- toplasm contains a diffused nervous system. Among all the observations that uphold this idea, we must cite one to which M. Gruber, a professor at Freiburg, in Breisgau, has recently called attention. This obser- vation was made on a large, ciliated Infusory, the Stentor, of which mention will be made so often here- after that it will be advantageous to give a full de- scription of it beforehand. The Stentor has an elongated body, broadened in front like a funnel, and able to fasten itself by its pos- OF MICRO-ORGANISMS. . 21 terior extremity. The edge of its peristome is covered by a belt of vibratile cilia disposed about a spiral line. The mouth occupies the most sunken part of the peristome. The body of the animal is striated with longitudi- nal bands; at the plane of the peristome, these bands take a different direction: they become transversal and spiral. In the interior of the protoplasm can be ob- served a contractile vacuole and a nucleus like a string of beads, made up of a large number of grains. This Infusory, like all the Ciliates, mul- . tiples by fission; a contraction is seen to take place in the middle of the body; the segment below the contraction generates a peristome similar to that of the upper seg- ment; then a second contractile vac- uole is formed, and soon the two segments represent two complete animals which possess all their or- gans. Nevertheless, the two Sten- tors continue to be united for a cer- tain length of time by a bridge of matter, located even with the point where the contraction took place; this bridge of matter gradually grows thinner and thinner and be- comes as fine as a thread. (See fig. 5.) Now, Gruber has observed that the two Stentors united by this ’s- 5. Stentor in pro- _ bridge of protoplasm exhibit perfect perso tieion: harmony in their movements; they always sway in the same direction at the same time; and this harmony is necessary, because the least contrariety of motion 22 LHL PS¥YCHLIG LILLE would suffice to break the feeble bond that unites them. Moreover, their vibratile cilia beat in unison. To explain this concordance in the movements of the twa animals, Gruber assumes that the entire mass of their protoplasm performs the function of a diffused nervous system, which has the effect of regulating their move- ments and of making them harmonize. We might add that the Infusoria possess not only a diffused nervous system, but that they must of neces- sity possess special nerve centres, endowed with dif- ferent functions. It will be remembered in fact that, under the influ- ence ofcertain poisonous agents, death is not simultane- ous throughout all parts of the organism. What ceases first are the voluntary movements of the large cilia; the movements of the small cilia are able to per- sist much longer; and finally, when all the cilia have become immobile and rigid, the vesicle has still been seen to pulsate for an hour. This gradual death re- calls what we remark among the Vertebrates; under the influence of poisonous agents, the brain dies first, then follows the marrow, and lastly the bulb, which is the wl/imum mortens. . The Organs of Sense. All the Micro-organisms are endowed with sensibility; some, like the Infusoria, have exceedingly sensitive powers. But, hitherto, organs of sense anatomically differentiated have been found in only a very small number of species. Gen- erally, the protoplasmic expansions which we have above described under the name of pseudopodia are regarded as fulfilling the function of rudimentary organs of touch which advise the micro-organism of. the presence of objects which happen in its path; but these pseudopodia, which at the same time serve as OF MICRO-ORGANISMS. Za motor apparatus, do not exhibit any structure which especially fits them for the reception of sensory im- pressions. Similarly, Stein considers the vibratile cilia as organs of touch. As these are organs which have not undergone any differentiation, we shall not stop to consider them. The Infusoria belonging to the genus Cryptochilum (Maupas) carry at their pos- terior extremity a long rigid bristle, which M. Maupas regards as an organ of touch, intended to advise the animal of the approach of other Infusoria. We shall speak more at length of the organ of sight; this has been the subject of numerous treatises, some of which are quite recent and of the greatest interest to general physiology and psychology. Of all the organs of sense the eye is the one which is first differentiated. It is found in the organisms be- longing to the vegetable kingdom as well as in those belonging to the animal kingdom. While these small beings do not seem to possess any organ especially adapted by its structure for the reception of tactile, olfactory, or gustatory impressions, a large number already exhibit an ocular spot, that is to say a differ- entiated organ, for the purpose of sight and for no other purpose. Let us first turn our attention to the eye of the Protozoa. It is chiefly in the group of Flagellates, and prin- cipally in the species that are colored green by chlo- rophyl (for example the Euglenz), that ocular spots are found; these spots which are colored a bright red, present themselves very clearly to the observation, for they are set off by the uncolored plasma of the anterior part of the body where they are generally located. Oculiform spots are also found in the species 24 TA EOP SVC. C Sits colored by yellow chlorophyl (Uroglena volvox, etc.). Generally, there is only one spot, situated at the base of the flagellum. This is seen especially in the Euglena viridis, a small flagellate infusory, which is very abundant in fresh waters, which it often covers with a thick green coating. In the Synura uvella, a colony-forming flagellate, there exist in each individual, in the anterior part of the body, numerous spots, varying from two to ten. Below we give an illustration representing the anterior extremity of the Auglena Ehrenbergii, ac- cording to Klebs. A large ocular spot is noticeable, in contiguity with the contractile reservoir. Ehren- berg, deceived by the appearance of these two or- gans, had taken the contractile reservoir for a nerve ganglion. It is not only in the large group of Protozoans that the red spots are met with; they are found also among the vegetable Micro-organisms. A large num- ber of green-colored zodéspores exhibit at the anterior, and Fig. 6.—Anterior extremity of : ; the. Buclenabaroalen reciente usually colorless, extremity of Kiebs° sik SK EEE A their: bodies, a. smallsréd* point Guaitesotic: ooh leon which seems to have exactly the ecole raed same structure as the red spot of the Euglene. It was on this fact that Stein based his opinion that the spot of Euglena is not an eye; to him it seemed im- possible to admit that the vegetable Proto-organisms could possess a visual organ. This is an excellent instance of a préor? reasoning. Later on we shall. see that Stein’s view has now been completely abandoned; the very opposite view is taken, for the OF MICRO-ORGANISMS. 25 eye of the Protista is considered as being destined to perform chiefly a vegetable function. Klebs was able to study the structure of the ocular spots, by employing a very ingenious artifice. When the Euglene are treated with a solution of sea salt, in the proportion of one part to one hundred, an enor- mous dilatation of the contractile vesicle, which forms a hollow in the protoplasm of the animal, is induced; now, as the red spot is, so to speak, glued to the vesi- cle, it undergoes the same dilatation as the latter does, thus greatly facilitating observation. By this treat- ment it has been observed that the spot is a small dis- coid or triangular mass, of jagged and irregular out- line; it is formed of two material parts; for a base it has a small mass of reticulated protoplasm, and in the meshes of the protoplasm there are small she of an oily substance, colored red. This red pigment, which has received the name of hematochrome, is not without its analogy with the green pigment of the chlorophyl, because this latter becomes red under certain conditions. For example, the chlorophyl pigment which fills the entire body of the Hematococcus pluvialis becomes red, when the animal enters into astate of rest; the stagnant spores of the alge also assume ared tint. So, also, in nu- merous plants, the parts of the flower destined to be- come red are green as long as they are enclosed in the bud. It is thus probable that the red pigment of ‘the Euglenoids is derived from a green pigment. What is the physiological significance of these spots? Ehrenberg considered them as eyes; hence the name Luglena (word for word, pretty eye), which he had given to a species of Flagellates provided with ocular spots. This interpretation had been anestioned 26 LILLE PSVCHIC LITE by all the authors of his time, especially py Dujardin. At the present day, however, naturalists have come back to it, in consequence of observations which have been made on other Micro-organisms that possess a more perfectly developed eye. | M. Pouchet has discovered in the Glenodinium polyphemus, which belongs to the group of Peridinia (or Dinoflagellates, according to the classification of Biitschli), an eye about the function of which there can be no mistake. This eye occupies a fixed place in the cellule of the Peridinium; it has a uniform location and position. It consists of two parts, the one a veritable crystalline humor, and the other a veritable choroid. The cry- stalline is a strongly refracting, hyalin, club-shaped body, rounded at its free end, which is always directed forwards, while the other end is immersed in the mass of pigment which represents the choroid. This latter is clearly determined; it forms a sort of hemispherical cap, enveloping the posterior extremity of the crys- talline. In one of the two forms of Glenodinium pol- yphemus, the choroid pigment is red; in the other it 1s black. , M. Pouchet has been able to establish that in the young animals the crystalline is first formed of six to eight refracting globes, which are merged into each other in order finally to constitute one unified mass. Also, the choroid is the result of a combination of the pigmentary granules which, at first sparse, group to- gether and finally form the hemispheric cap that covers the posterior extremity of the crystalline. In fact, the visual organ of this Peridinium is com- posed of exactly the same parts as the eye of a meta- zoon with one exception, the absence of the nerve OF MICRO-ORGANISMS. 27 element. This is not at all differentiated, but remains diffused, like the whole nervous system. M. Pouchet calls attention to the interest which his observation affords trom a taxonomic point of view. The Peri- dinia have sometimes been classed among the vege- tables; the presence of starch and of cellulose in their protoplasm has induced Warming to classify them among the Diatomacee and Desmidiacez. It is ad- ‘mitted to-day that certain Peridinia possess an eye, an organ which has hitherto beén considered as the exclusive attribute of animals. Nothing more clearly emphasizes the altogether artificial character of the distinction between animals and vegetables than the results of dealing with Micro-organisms. Before leaving the Peridinia, we would remark that these small beings afford an interesting fact from the point of view of the history of the Protozoa; they are provided with a long flagellum; they exhibit in ad- ditionan equatorial line on which formerly a crown of vibratile cilia was thought to be recognizable: this supposed co-existence of a flagellum and of cilia had determined the naturalists to form a group of Cilio- flagellates, serving as a transition between the Fla- gellates, properly so-called, and the Ciliates. Since then it has been discovered that the Peridinia do not possess vibratile cilia; what had given rise to this er- ror is the presence of a second flagellum on the level of the transverse line which we have just described; the movements of this flagellum have the appearance of vibratile cilia in motion. Some time before the investigations of M. Pouchet, M. Kiinstler (of Bordeaux) had discovered, in a Fla- gellate of the genus Phacus, a red eye which is also formed of two parts; it is composed of a homogenous 28 THES SY CHI COLLIE globule, acting as acrystalline humor, and surrounded by a red pigment, acting the part of the choroid. Before M. Kiinstler, Claparede and Lachmann, in their important work on Infusoria and Rhizopods, had described a similar visual organ in the Freza ele- gans, a ciliated infusory of the family of Stentorines. ‘Immediately behind the point of truncation,” say they, “there is found a lunate spot of intense black, evidently belonging to the category of these phenom- ena which M. Ehrenberg, in the Ophryoglene, for ex- ample, calls an eye or an ocular spot. The significance of this spot has never been known. It was often very much denser than that of the Ophryoglene, and some- times there was discovered behind it a very trans- parent corpuscle, which involuntarily gave rise in the mind to the idea of acrystalline humor. We cannot, however, add much of importance to this idea, since the functions of a refracting apparatus must neces- sarily remain problematic, as long as we do not dis- cover behind it a nervous apparatus fitted to perceive the impressions received.” This last conclusion seems to us excessively cau- ’ tious. The co-existence of a pigment and ofa crys- talline humor amply suffices to characterize a visual organ. As to the nerve apparatus susceptible of per- ceiving impressions, it is replaced by the protoplasm, which, as is well known, is sensitive to light. Even before that, in 1856, Lieberkiihn had discov- ered in a ciliated infusory, the Panophrys flavicans, an ocular spot, composed of a convex crystalline humor, having the form of a watch-crystal enveloped by pigment and placed on the convex side of the oral fosse. In another species, the Ophryoglena atra, he found black pigment, but no crystallme humor. OF MICRO-ORGANISMS. 29 It is impossible to believe that these organs are not eyes, for they have the same structure as the eyes of comparatively higher classes of animals, such as certain worms, turbellaria, rotifers, lower-class crusta- ceans, etc; all these organs are similarly formed of a small crystalline globule enclosed in a small mass of pigmentary matter. The identity of structure natur- ally leads to the assumption of the identity of functions. The eye of the Euglena is the simplest of all; it is even reduced to the maximum point of simplicity, as itis composed of a spot of pigment. What induces us to believe that this spot is a visual organ, is the presence of this pigment. In fact this pigment is found in the most elementary visual organs. Asecond argument might be advanced; the red pigment of the Euglena exhibits the same re-actions as the coloring matter that fills the rods of the retina in the Verte- brates. From among these re-actiorfs common to both, we cite the decoloration under the influence of light (Capranica). Whatever the case may be, one thing is certain, namely that the Euglena is very sensitive to the light. When they are kept in a vessel, they are in- variably seen to cover the side exposed to the light. M. Engelmann has observed that light acts very strongly upon this small animal; it does not act directly on the spot of pigment, nor, as was formerly thought, on the flagellum, but on the protoplasm which is located in front of the spot. The special micro- spectral object-glass that M. Engelmann constructed, enables us to see that the Euglene always congregate in the band F to G of the spectrum. So far as the vegetable Micro-organisms are con- 30 THE PSY CHLCRl Lite. cerned, we have already mentioned that a large num- ber of the algz zodspores exhibit, in the anterior part of their body, ocular spots of a beautiful ruby color: these are organs that probably have the same struc- ture as the red spots of the Euglene. Moreover, it is probable that certain Microphytes possess more complex visual organs, composed of red pigment and of a crystalline humor. M. Balbiani has recently testified to this fact in the case of the Pandorina mo- rum, a spherical colony of green micro-organisms; in each colony there exists a certain number of individ- uals which possess a red spot, the shape of which is perfectly circular; if this spot be examined under a glass of very high magnifying power, one can readily see that it is formed of a small spherical globule, cov- ered, on a portion of its surface, by acap of red matter. This observation is all the more interesting because it is made on a being, the vegetable nature of which is to-day no longer doubted; the Pandorina are Volvocinz which modern botanists place.among the alge. (Weare glad to give our readers the earliest communication concerning this fact.) In describing the eye of the Protista, we said that the eye is the only organ of sense which is distinctly differentiated in these lower beings. But, perhaps, this assertion is too sweeping. Some species appear armed with small organs which could easily be in- vested with a sensory function. In this respect, we may cite the Loxodes rostrum, a beautiful ciliated in- fusory, remarkable for its proboscis and for the mus- cular sheath which closes its mouth. This animal exhibits along the dorsal surface a row of small organs which, by their structure, seem destined to act a part in performing the function of hearing. They are OF MICRO-ORGANISMS. seh formed of a vesicle, the centre of which is occupied by a refracting globule; they are called the vesicles of Miiller, after Johannes Miiller, who discovered them. The auditory organs which have been observed in Worms and the Coelenterata are apparently composed of a vesiculiform capsule enclosing a solid concretion, called otolith. Thus it is possible that the vesicles of Miller may be auditory vesicles. Up to the present time this organ has not been met with in any other species of Protozoa. ahs NUTRITION. After studying the organs, let us pass to a study of their functions. It is not our intention to devote special chapters to irritability, instinct, memory, reasoning, and the powers of volition in Micro-organisms. This would lead to diffuseness of treatment. Our method will be quite different. We shall describe as a whole all the dif- ferent manifestations of psychical activity attendant upon the actions of Micro-organisms in the exercise of the important functions of their existence. The present chapter will be devoted to psychical phe- nomena connected with the act of nutrition. All living matter possesses the power of continu- ally increasing its mass by the inward reception of materials, and of simultaneously decreasing the same through the combustion of its substance with the oxygen of the atmosphere. The first of these pro- cesses is called nutrition, and the second, respiration. We shall first examine the psychical phenomena which precede and determine the act of respiration. These phenomena are often very simple and of little 32 LULL IES Y GAL C eens significance. If the Micro-organism lives in the water, which is most frequently the case, the oxygen contained in solution therein passes directly through the cellular cuticle by dialysis and comes in contact with the body of the protoplasm; in which case the process of respiration is solely a chemical phenome- non. But it may happen that a minute organism chances into a medium containing little or no oxygen- gas; amid these new conditions where it becomes nec- essary to move towards sources emitting oxygen by voluntary effort and directed motion, it has been dis- covered that a great number of Micro-organisms, and particularly Bacteria, are capable of detecting the ex- pansive power exerted by oxygen in the liquids in which they are found. When bacteria of putrefied matter are put in a drop of water containing no oxy- gen but in which have been placed chlorophyll alge, or green Euglenz, or grains of chlorophyl obtained by crushing green cellules, nothing happens in the first instant; but if the preparation.-be illuminated so as to allow the chlorophyl to act, the bacteria are seen to exhibit very rapid movements and to proceed, al- together, towards the points of the preparation where the generation of oxygen is taking place, that is to say, about the grains of chlorophyl. Under these con- ditions a chemical exchange is instituted between the chlorophyl and the aérobious Bacteria: the Bacteria disengage carbonic acid gas and absorb oxygen; the chlorophyl fastens upon the carbon of the acid and sets the oxygen at liberty. If the preparation be darkened the Bacteria cease assembling about the chlorophy! grains, which, hid from the light, cease to disengage oxygen. The clustering begins anew, ifa ray of sunlight is again let touch the chlorophyl. OF MICRO-ORGANISMS. 33 Analogous facts have been observed under circum- stances somewhat different. In a preparation from the intestines of a silk-worm, M. Balbiani has seen Bacteria which were uniformly distributed throughout all points of the preparation, gather about the green and undigested cellules of the leaves contained in the intestines, and bury themselves in them as if to par- take of them. In other instances, the same naturalist has observed that Bacteria developed in a drop of silk-worm’s blood, would gather, after a while, about the globules of the blood; undoubtedly for the purpose of seizing the oxygen being absorbed by them. Upon the basis of these facts M. Engelmann has established the method called the Bacteria method. He regards bacteria as a living reagent which enable us to reveal the trillionth part of a milligram of oxy- gen, that is to say, a quantity scarcely greater, accor- ding to the calculations of physicists, than a molecule. This curious method enables us to explain biological problems which had hitherto remained unsolved. Before this, it was not known whether the colorless protoplasm of green plants could or could not disen- gage oxygen. It is now known, thanks to the bacte- ria, that grains of chlorophyl are the only points about which the liberation of oxygen takes place. The same method has enabled us to prove, in the variegated plants, that the maximum liberation of oxygen coin- cides with the maximum absorption of light. Thus, in the case of green alge, the red and the violet colors of the spectrum are the spots where the bacteria ac- cumulate the thickest; consequently here is where the liberation of oxygen is greatest. Now, these colors correspond to the lines of greatest absorption in the spectrum of chlorophyl. In the case of brownish vel- 34 THE PSYCHIC LIFE low cellules, the maximum ‘action is in the green; in the case of bluish green cellules, in the yellow; in the case of red cellules, in the green. The author has concluded from this that there exists a series of col- oring substances which, like chlorophyl, have the power of resolving carbonic acid gas; he calls them chromophyls. In the same way, moreover, this method enables us to solve the question of the distribution of energy in the solar spectrum. As M. Engelmann has remarked, it is interesting to see the Bacteria come to confirm our theories as to the composition of solar hight. Bacteria are not the only organisms that eagerly make towards points where oxygen is to be found. A large number of other Micro-organisms act in the same way when they happen into a medium lacking oxygen. M. Ranvier has noticed that if a preparation containing leucocytes, screened from air, be examined for a certain length of time the cellules will be*seen to throw out long filaments towards the part that faces the air-side of the preparation. It appears, then, that a rudimentary oxygen- sense exists in the protoplasm of Proto-organisms. This sense does not merely apprise the organism of the presence of oxygen; it enables it, further, to gauge the tension (expansive power) of the gas. So that, when the tension becomes too powerful, the or- ganisms are seen to flee before it. 1B Bie The mode of nutrition among Micro-organisms is not uniform—a fact which ought not to appear remark- able when we bear in mind that this immense group is made up of all manner of heterogeneous beings that OF MICRO-ORGANISMS. 35 have nothing in common save the microscopic little- ness of their bodies and. the simplicity of their structure. Three main types of nutrition may be briefly distinguished. 1. Vegetable nutrition, or according to Biitschlh’s expression, holophytic. This is the method of nutri- tion among animal or vegetable cellules that contairm chlorophyl and that nourish themselves by forming organic nutriment from ingredients taken from the surrounding medium. It is hardly necessary to call to mind that the function of chlorophyl is that_of nu- trition and not of respiration. This phenomenon was formerly termed the diurnal respiration of plants. The expression involves several mistakes. Enough to say that vegetables respire as animals do, by uniting with oxygen, and that that respiration continues the same both day and night. The function of chlorophyl is by no means respiration; its office is to decompose the carbonic acid gas of the air and to seize the carbon, which serves the plant in forming ternary or qua- ternary substances. This chemical work is performed by all chlorophyl organisms when influenced by the radiation of light. , Chlorophyl does not belong exciusively to the veg- etable kingdom. A large number of animal Micro- organisms are colored green by this pigment; they are met with principally in the important group of Fla- gellates. Their assimilative organs, which are like- wise found in all green plants, bear the name of chro- “matophores; they have lately formed the subject of interesting investigations. The chromatophores are small bodies of protoplasm which are distinguished from protoplasm in general by their having assumed an individual structure. 36 THE PSVCHIC LIFE These little bodies, which in the vegetables are called Jeucites, have a granular and reticulate structure; they are impregnated with a coloring substance, at times green, at times yellow, and at times brown, as the case may be; in fact, several coloring substances are present, which, by intermixture in different propor- «tions, form colors of many varieties. The best known, after green chlorophyl, is yellow chlorophyl or dato- min. The latter coloring substance can be absorbed by alcohol. The Euglenoidide, the Chlamydomonadide, and the Volvocine exhibit enormous chromatophores. In the case of the Euglene, the chromatophores are formed of small discoid plates; they are situated di- rectly under the cuticle, so that the light can act upon them (see fig. 4). In certain-species of Flagel- lata, they are exhibited under the cuticle in the form of two large plates which envelop the protoplasm like a cuirass formed of two pieces. The Chlamydo- monadidze and the Volvocine have green chromato- phores, disc-shaped, and very small. In the centre of the chromatophore a small bright space is observed which was formerly thought to be filled with chlorophyl; in reality, itis a minute solid globule which shows an extremely close analogy with the substance composing nuclei, or nuclein. It ex- hibits the same chemical reactions; it actively absorbs coloring matter and grows extremely brilliant when treated with acids. Schmitz gives this little body the name of pyrenoid (from pj, nucleus). It is around the pyrenoid, and probably through its action, that starch forms; it is deposited in grains or re-unites in a ring about the pyrenoid, a fact easily ascertained by coloring them with iodine. OF MICRO-ORGANISMS. 37 Production of starch has also been observed in the colorless Flagellates, as for instance in the Polytoma uvella. ‘These latter do not have chromatophores, but Kinstler, and after him Fisch, has noticed that every grain of starch is attached to a small mass of colorless protoplasm which is the focus of formation for the grains. This is precisely what happens in vegetable organisms where colorless starch-leucites are found: This little mass of protoplasm always faces the hilum of the starch-grain. As the function of the chromatophores is exercised only when subjected to the influence of light, it fol- lows that green Micro-organisms must have light in crder to nourish themselves. A quite remarkable fact may be adduced in this connection. On examining the kingdom of Protozoans as a whole, it will be seen that a striking coincidence exists between the presence of the eye and the presence of the chlorophyl pigment. Organisms hav- ing an ocular spot are in most cases provided with the chlorophyl pigment, or, in other words, nourish themselves as plants do, by generating starch through the action of light. This fact proves that sensibility to light is in some manner dependent upon the chlorophyl function. If Flagellates possessing chro- matophores, that is organs generating starch, have ocular spots at the same time, it is because these ru- dimentary eyes-enable them to find their way towards the light, which is the necessary agent of chlorophyl action. Accordingly, all Micro-organisms having eyes nourish themselves as plants do. In their case, the object of the eye is to direct the performance of a vegetable function. It is interesting to note in this connection that the 38 LAT EX PSV CHL CRLTAL! Euglene might nourish themselves as animals do, for they have a mouth and a digestive apparatus. The buccal, or oral, aperture opens in the anterior end at the base of the flagellum, and is connected with a short gullet or esophagus (see fig. 6, the mouth and gullet of an Euglena). Nevertheless, the Euglena is never seen using its mouth for swallowing alimentary particles. A quite curious problem is involved here. If it is true, as has been claimed, that it is the function that makes the organ, how do we explain the existence and especially the genesis of this digestive apparatus which performs zo function? It.is the presence of chromatophores that prevents certain Flagellates from feeding hke animals; somuch _ so in fact, that the digestive apparatus performs its functions in Flagellates which have no chromato- phores and are not provided with chlorophy! pigment, an instance of which is seen in the Peranema. ‘The Peranema is, further, an exceedingly voracious animal. We must note also that the Peranema does not exhibit ocular spots like the green Euglena; and moreover, it has no need of such, since it does not have to seek the light to generate starch. All these phenomena are interdependent. The influence exerted by light upon the green organisms of both kingdoms has been ascertained by different scientists. Light at a certain degree of intensity attracts them, and at a greater de- gree, repels them. Some years ago M. Strassburger conducted a series of connected experiments upon the movements of green spores towards light. It was ob- served, here, that the grains of pigment in the in- terior of the cellules, when under the influence of OF MICRO-ORGANISMS. 39 solar radiations, executed movements and set out- wards in all directions. 2. Nutrition by endosmosis, or saprophytic. The or- ganism nourishes itself by absorbing through the whole surface of its body liquids containing the pro- ducts of vegetable or animal decomposition. Sapro- phytic beings are found in putrid waters or in infu- sions. This manner of nutrition may be considered, from the point of view which now engages us, as the most simple of all; it probably allows of a search for food, but it is certain that no movements are involved which are designed to draw the food into any possible digestive apparatus. 3. There is now a.last mode of nutrition, of which we shall treat in minute detail; namely, animal nu- trition, where the Micro-organism seizes solid alimen- tary particles and nourishes itself after the fashion of an animal, whether it be by means of a permanent mouth or by means of an adventitious one, improvised at the moment of need. This manner of nutrition is the process employed by higher animals. Among the lower organisms, it is met with in most of the In- fusoria, in the Sarcodines, in many of the Mastig- ophores, and in others. Respecting the Micro-organ- isms. belonging to the vegetable kingdom, we find nutrition by endosmosis and chlorophyl nutrition; the Protophytes never possess a mouth and never absorb solid foods. Animal nutrition requires very remarkable psy- chological faculties in the organism practicing it. These manifestations of psychic life, the progressive complexity of which we intend to trace in starting from the simplest protozoic forms and arriving at the higher—prove that these animalcula are endowed with 40 THE RSV CHL LT Las memory and volition. We shall group our remarks under the two following heads: a. The choice of food; and 2. The movements necessary for the prehension of food. | The Micro-organisms do not nourish themselves indiscriminately, nor do they feed blindly upon every substance that chances in their way. Also, when they ingest food through some point or other of their bodies, they understand perfectly how to make a choice of the particles they wish to absorb. This choice is some- times quite well defined, for there are species which feed exclusively upon particular foods. Thus, there are herbivorous Infusoria and carnivorous Infusoria. Among the herbivorous ones may be classed the chilo- dons which feed upon small Algze, Diatomacez, and Oscillaria. The parmecia live principally upon Bac- teria. The Leucophrys is a specimen of the carnivo- rous class; it devours even the smaller animals of its own kind. The Cyrtostomum leucas eats everything, as do the Rotifers. , Though the fact of an exercise of choice in taking food is settled beyond question, yet the interpreta- tion of this phenomenon is a matter of much uncer- tainty.’ Some writers, as Charlton Bastian for in- stance, explain this choice of food as an affinity of chemical composition existing between the organism and the nutriment. This idea does not lead to any- thing. Others compare the discrimination made by the Proto-organism between objects presented to it, to the action of a magnet which in some way selects particles of iron that have been mixed with particles of other substances. The latter interpretation is an evidence of the tendency evinced by some naturalists, OF MICRO-ORGANISMS. 41 of endeavoring to identify the attributes of living or- ganic matter with the physico-chemical properties of the mineral kingdom. In our opinion, the only question demanding con- sideration is whether the choice of food, in the case of Proto-organisms, does or does not result from a psychical operation, similar, forexample, to that which takes place in higher organisms. We have received a noteworthy communication from M. E. Maupas, upon this subject, which tends to establish that the choice of food is not the result of individual taste in the Micro-organisms, but is determined by the or- ganic structure of their buccal apparatus which does not allow them to receive other forms of nutriment. We must closely examine, therefore, the mechan- ism for prehension of food. . The following is what occurs when the Amceba, in its rampant course, happens to meet a foreign body. In the first place, if the foreign particle is not a nutri- tive substance, if it be gravel for instance, the amceba does not ingest it; it thrusts it back with its pseudo- podia. This little performance is very significant; for it proves, as we have already said, that this micro- scopic cellule in some manner or other knows how to choose and distinguish alimentary substances from inert particles of sand. If the foreign substance can serve as nutriment, the Amceba engulfs it by a very simple process. Under the influence of the irritation caused by the foreign particle, the soft and viscous protoplasm of the Amceba projects itself forwards and spreads about the alimentary particle somewhat as an ocean-wave curves and breaks upon the beach; to carry out the simile that so well represents the process, this wave of protoplasm retreats, carrying with it the 42 FHI PSY CHT G LLL, foreign body which it has encompassed. It is in this manner that the food is enveloped and introduced into the protoplasm; there it is digested and assimilated, disappearing slowly. There are cellules found in the inner intestinal walls of lower animals which effect the prehension of solid foods in the same manner as the Amceba cellule: they are called phagocytes. This mode of prehension is beyond contradiction the most simple imaginable; for the prehensile organ is not as yet differentiated. Every part of the proto- plasm may be made to serve as a digestive cavity in enveloping the foreign substance. From the special standpoint of prehension of food, we may place the Actinophrys sol above the Amceba. This animalcule is a small microscopic Ileliozolarian abounding in fresh-water ooze. It casts out long, slender, filamentous pseudopodia from every part of its body. When its prey or any alimentary substance gets into the midst of this mass of filaments, the fila- ment affected quickly draws back, carrying the nutri- tive matter with it towards the body proper of the Actinophrys. In other instances, the filaments, anas- : tomosing themselves, form a sort of envelope about the prey. At the instant the substance comes within a short distance of the cellule, a part of the protoplasm composing the mass projects itself forwards, and en- compasses the food, which is carried back and envel- oped in the midst of the protoplasm by a process anal- ogous to that seen in Amceba. In the case of the Actinophrys any part of the body could serve as a way of entry for food, that is to say, could act the part of a mouth. To use the expression of W. Saville Kent, it is a pantostomate being. In OF MICRO-ORGANISMS. 43 other species of higher organization, this mode of ali- mentation is rendered impossible by the cutitcle which encompasses the body; tne formation of a cuticle im- pervious to solid foods creates the necessity of a buccal orifice through which food may enter into the interior of the protoplasm. A curious graduation in these phenomena is noticed here. Thus there are organisms destitute of a per- manent and pre-existing mouth; their mouth is 1m- provised as the occasion demands, is adventitions, so to say, and the reason that these organisms are ranked higher than the preceding ones, is that the mouth is invariably formed in the same place. In this connection we may examine a small flagel- late Infusory which abounds in impure waters, the Monas vulgaris. It carries a long flagellum attached to its anterior extremity, which when not in motion, is coiled up against the body. At the base of the flagel- lum the protoplasm projects a pellucid substance in the shape of a lp. This protuberance is hollow, containing a vacuole filled with liquid. Cienkotvski has described how these different organs act. The Bacteria and Micrococcus, which constitute: the food of the AZonas, are pulled into the latter’s neighborhood by strokes of the flagellum; at that instant, the animal becomes conscious of the proximity of these other bodies, forthe protuberance which hes at the base of the flagellum extends towards the corpuscule, envelops it in its own substance, and pulls it back into the interior of the Monad’s body. Bititschli has made an analo- gous observation with the Ozkomonas termo. The prehension of food comprehends, here, three phases, in two of which the organism manifests psychical activity: firs/, attraction of food by means 44 PHE PSY CHLG AAP of the flagellum ; second, formation of the vesicle which extends towards and envelops the food, when the latter has come near; ¢Azrd, absorption of the food. The Acinetez are organisms that move about very little ; they frequently remain fixed to a pedicle their whole life long. They have no cilia, but exhibit ra- diating prolongations, more or less numerous, and sparse or grouped in tufts, as the case may be. These filaments are suckers, provided at the end with a small air-hole. When a thoughtless Infusory swims into the territory of an Acineta, the latter arrests it by means of its stout filaments and fastens upon the former’s body the cup-shaped extremities of its suckers, which make avacuum. The protoplasm of the Ciliate thus cap- tured, slips slowly through the suckers as through tubes, and is gathered together in the interior of the Acineta in the form of small drops. In the Acinete, accordingly, particular organs are adapted to the pre- hension and absorption of food. Corresponding to the greater complexity of physical action, the psy- chical process necessary for the act of prehension has likewise become more complicated than is the case with the Amceba. The Acineta is obliged to direct its sucker towards the Infusory which is within its .reach, and consequently the animal is obliged to de- termine the position of its prey. There are Acinetide that exhibit prehensile or- gans more perfect than those just noticed. Such are the Hemiophrys. They have both sucker tentacles and prehensile tentacles. The latter are filaments which the animal throws about its victim like a lasso, thus enveloping and rendering it motionless, while it pro- ceeds to feed upon it by means of its suctorial ap- paratus. OF MICRO-ORGANISMS. 45 Now, do these Acinetide show any preference of choice among the Infusoria that chance to fall within reach of their tentacles? M. Maupas, who has made an especial study of these organisms had at first admitted this preference in choice. But he afterwards rejected the notion. In 1885, he writes us: “I find quite another explanation of the impunity with which the Coleps hirtus can throw itself upon the terrible suckers of the Podophrys fixa. The stout shell with which this little Infusory is enveloped, serves it asa shield and guards it from the deadly grasp of the Acine- tide. The Acinetide do not seize the Coleps because of any dislike of the latter, but because they are un- able to seize them, and their inability results from the peculiar structure of the Coleps’ tegumentary en-- velope. The Paramecia which also escape unscathed, are similarly provided with a tegument of high resist- ing power, which serves them as a protection in this contingency. The Stylonichia histrio, like all other Stylonichiz, has a very soft tegumentary envelope. They are accordingly seized and devoured by the Acinetide without difficulty. The detailed knowledge of the differences of structure in the tegumentary en- -velopes has caused me to abandon the idea of a pre- ference or dislike in the choice of those victims which serve as food for the Acinetide. Of the prey that passes by, they catch what they can and not what they want to.” In a large number of species the prehension of food is preceeded by another stage, the search for food, and in the case of living prey, by its capture. We shall not investigate these phenomena among all the Protozoa, but shall direct our attention especially to the ciliated Infusoria. Their habits are a remarkable 46 THE PSYCHIC LIFE study. If a drop of water containing Infusoria be placed under the microscope, organisms are seen swimming rapidly about and traversing the liquid medium in which they are in every direction. Their movements are not simple; the Infusory guides itself while swimming about; it avoids obstacles; often it undertakes to force them aside; its movements seem to be designed to effect an end, which in most instances is the search for food; it approaches certain particles suspended in the liquid, it feels them with its cilia, it goes away and returns, all the while describing a zrg- zag course similar to the paths of captive fish in aquariums; this latter comparison naturally occurs to to the mind. In short, the act of locomotion as seen in detached Infusoria, exhibits all the marks of volun- tary movement. | It might also be mentioned that every species manifests its personality in its mode of locomotion. Thus, as a rule, the Actinotricha saltans when placed in a preparation where it finds itself at ease, remains for a few moments perfectly immovable. Then, of a sudden, it dashes forward with the rapidity of lght- ning and disappears from the field of vision. Fora time it darts about to the right and to the left, and © then once more assumes its state of immobility. It can move with the greatest agility through masses of débris, in the midst of which, bending and twisting, it slips about with wonderful nimbleness. The Zagynus crassicolis, on the other hand, moves along at a pace quite constant and uniform, neither slow nor rapid. It searches about among alge and fragmentary parti- cles. The Perttromus Emme moves slowly. It runs lazily over the Alga, where it seeks its nutriment, and does not stray from them to venture into the open water. OF MICRO-ORGANISMS. 47 Concerning the prehension of foods and the search for nutriment on the part of Ciliates, we can do no better than to quote entire a note which M. E. Maupas has been pleased to send us upon the subject. We had put to him two questions: /7zrs?¢, do the Ciliates hunt their food? Second, while in quest of live prey, do the Ciliates called hunters make an actual hunt, involving the espial of prey from a distance and the voluntary pursuit of the same in the circuitous paths they fol- low? M. E. Maupas after having once more had re- course to observation, briefly recapitulates his opinion in the following lines: “From the standpoint of prehension of food, the Ciliates may be divided into two great groups: 1. Ciliates with alimentary vortices; 2. Hunter Ciliates. “Tn the first group the mouth is always held wide open, and along with the nutritive particles which the current of thevortex keeps constantly sucking in, we may at will cause other, absolutely inert and indigesti- ble, particles to take the same course; for instance, such substances as granules of carmine, indigo, and rice-starch. These granules, totally unfit for nutritive purposes, pass through the body of the Ciliates along with the genuine nutriment and are finally cast out intact with the excrement. I think, therefore, we may affirm that the species having alimentary vortices exercise no real choice in selecting their foods, and that they absorb indiscriminately all corpuscules which by reason of their form and density admit of being seized and drawn into the alimentary whirlpool. “In the case of the hunter Ciliates proper, the mouth is constantly closed. The act of absorbing each object captured is accomplished by a process of de- 48 THLE: PSYCHIC LILI glutition comparable in every phase to the like pro- cess in higher animals. Furthermore, these species feed only upon living prey, which they capture and entrammel by means of their trichocysts (wid. Archives de Zoologie, Vol. I. 1883, p. 607 and ff.). By this very act they exercise a choice in the selection of food. But this manifestation of choice is not, in my opinion, the result of preference, or of individual taste, but is the consequence of the peculiar construction of their buc- cal apparatus, which does not enable them to take other and different nourishment. “These hunter Infusoria are constantly running about in quest of prey; but this constant pursuit is not directed towards one object any more than an- other. .They move rapidly hither and thither, chang- ing their direction every moment, with the part of the body bearing the battery of trichocysts held in ad- vance. When chance has brought them in contact with a victim, they let fly their darts and crush it; at this point of the action they go through certain manceu- vres that are prompted by a guiding will. It very seldom happens that the shattered victim remains motionless after direct collision with the mouth of its assailant. The hunter, accordingly, slowly makes his way about the scene of action, turning both right and left in search of his lifeless prey. This search lasts a minute at the most, after which, if not successful in finding his victim, he starts off once more to the chase and resumes his irregular and roving course. These hunters have, in my opinion, no sensory organ where- by they are enabled to determine the presence of prey at a distance; it is only by unceasing and untiring peregrinations both day and night, that they succeed in providing themselves with sustenance. When prey OF MICRO-ORGANISMS. 49 abounds, the collisions are frequent, their quest profit- able, and sustenance easy; when scarce, the en- counters are correspondingly less frequent, the ani- mal fasts and keeps his Lent. The Zagynus crassicolis, accordingly, never sees its victim from a distance and in no case directs its movements more towards one object of prey than towards another. It roams about at random, now to the right and now to the left, im- pelled merely by its predatory instinct—an instinct developed by its peculiar organic construction, which dooms it to this incessant vagrancy to satisfy the re- quirements of alimentation. ‘‘The vorticel Infusoria, when in a medium abound- ing in food, are almost entirely sedentary in their habits, only making slight changes of position. But if they are placed in a medium affording but little nu- tritive material, they become as migratory as the hunt- ers, and are seen to race about in all directions search- ing for more abundant nutriment. It is hard to find a more perfect illustration of the influence exerted by the conditions of a medium upon the habits and customs of animals. “The Leucophrys patula is a type distinctively car- nivorous and possessed of an extremely voracious ap- petite, a fact which explains its power of multiplica- tion, one of the greatest I have studied. "Withatem- perature of 25° in my laboratory I have recently seen ~ it separate by fission seven times in twenty-four hours, that is to say, a single individual produces from itself | just one hundred and twenty eight others in that time. In constant pursuit of its prey, it seizes its vic- tims by the two stout vibratile lips with which its mouth is armed, and swallows them alive and whole. The victims may be seen struggling and tossing about 50 PHEHPSVGHLCCE AI for a time in the interior of the Leucophrys’s body and afterwards to expire slowly under the action of the digestive juices of the vacuole in which they have been enclosed. Placed in a medium well-stocked with small Ciliates, the Leucophrys have their bodies con- stantly crammed with victims swallowed in the man- ner above described. Like the other hunter Ciliates the Leucophrys does not espy its victims from a dis- | tance and does not guide-itself towards them. It simply darts about from right to left, every moment changing its direction. It thus increases its chances of coming in collision ‘with its prey and every time that one of its unfortunate victims falls in contact with its vibratile lips, it is seized, irresistibly drawn towards the mouth and swallowed within less than a tenth of a minute.”’ Certain hunter Infusoria have methods of pursuit and capture which deserve to be examined separately. Claparede and Lachman in their excellent work upon Infusoria and Rhizopods, have minutely described the manner in which a large Infusory, the Amphileptus Meleagris, attacks the Hpzstylis plicatilis. The Epis- tyfts are colonizing vorticels of which certain individ- ual members attain a size of not less than o-21 mm. The L£pistylzs form aborescent groups, the ramifica- tions of which are quite regularly dichotomous. These ramifications all grow at exactly the same rate and the individual branches all rise to the same height, rep- resenting what is called, in botany, a corymbous in- florescence. “We were observing one day,’ says Claparéde, ‘‘in the hope of seeing what would come > of the manceuvre, an Amphileptus, which was slowly creeping upon a colony of Lpistylis. The way-in which it approached the Vorticels, feeling them, so to ; OF MICRO-ORGANISMS. 51 speak, and partly enclosing them in its pliable body, already seemed suspicious. At last, it made a direct attack upon one of them by fastening itself upon the upper part of its body. It opened its huge mouth, which is never to be seen except when the animal is eating, and slipped over the /fzszty/7s like the finger | of a glove being drawn upon a finger of the hand. We saw the sides of the buccal aperture (which are capable of being dilated in a truly astonishing man- ner) slip slowly over the peristome and upon the body of its prey, and then draw together about the point where it was made fast to the pedicle. The cilia cov- ering the body of the Amphzleptus began to shake with that peculiar motion which is always noticed when a ciliated Infusory secretes a cyst. At the expiration of a moment or so, a fine line was seen to appear around the whole body which continued to spread so as soon to form the cyst.’”’ (This might be called a cyst of digestion.) ‘The phenomenon as a whole is quite simple. An Amphileptus approaches an Lfi7stylis devours it and encysts itself upon the spot, the victim being still attached to its pedicle. It then en- deavors to wrench the /fzstylis from its point of at- tachment by twisting; it turns on its axis from left to right and then from right to left, successively; when it has succeeded, it continues its work of digestion, and occasionally divides in two within the cyst itself. During the last stage of digestion, it rests for a while, when it-commences again to turn about in the cyst, evidently seeking to disengage itself. At the close of a certain number of hours, the cyst breaks. The Amphileptus issues forth and starts in quest of another victim.’’* * Etudes sur les I:ifusotres et les Rhizopodes, Vol. Il. p. 166, 1861. ca 52 THE PSYCHIC LILLE The hunter Infusoria are frequently armed with trichocysts. Trichocysts are urtical filaments which serve the animalcula provided with them to disable or wound other micro-organisms. A large unmber of Infusoria, the Paramecia, the. Ophryoglene, etc., use their trichocysts as organs of defense. With other species, of which we shall speak more at length, the trichocysts are organs of offense. They are located either in the sides of the mouth or in parts adjacent thereto; this is the case with the Lacrymaria, the Didinium, the Enchelys, the Lagynus, the Loxophyllum, and the Amphileptus. These latter animalcula attack the live prey that constitutes their food, in the following manner. They dash upon their victim and bury the trichocysts with which they are armed, into its body. The victim is immediately brought to a halt, whereupon the hunter seizes it and swallows it. So, when the Zagynus Elon- gatus intends to seize a victim that has fallen into its vortex and has thus been drawn into the neighbor-. hood of its mouth, it throws itself swiftly forward. At. the moment of contact the hunted Infusory becomes suddenly paralyzed and remains perfectly motionless. This paralysis is evidently caused by the trichocysts which line the esophagus of the Lagynus and with which the latter has transpierced its prey at the mo- ment it came in contact by its anterior extremity.*” In a higher stage of organization, the Microzo6én possessing a mouth changes its position in order to intercept its prey, and give it chase. The Didinium Nasutum (Stein), a carnivorous In- fusory and one of the most voracious of our fresh stag- nant waters, operates in a more complicated manner: * Maupas, op. cit., p. 495. OF MICRO-ORGANISMS. 53 it casts its trichocysts upon its victim from a distance. The importance of this instance induces us to stop here a moment. The Didinium (fig. 7), ic, 1, 2S regards the general We shape of the body, may ‘a;" be compared to a dimin- utive cask, rounded off at one of the ends and term- inated at the opposite ex- tremity by an almost level surface from the midst of which rises a conical pro- jection quite strongly Fig. 7.—Didinium nasutum, enlarged marked. This projection two hundred diameters. The figure rep- . Rohe! resents a Didinium overpowering a Fa-18 an Organ of deglutition ramecium aurelia. The nettle-like fila- : 2 ments discharged by the Didintum are (swallowing); a longitu- seen on all sides ofthe Paramecium; *. te rt : : while the latter, already seized by the dinal striation is noticed tongue-shaped organ of the Dzdinzumz, is being gradually drawn towards the buc- here formed of minute cal orifice (after Balbiani). solid rods, of extreme ten- uity and independent of the sides. These organs are the weapons used by the Didznzum in attacking the live prey which constitutes its sole nourishment. Not only does it attack and devour animalcula almost as large as itself, but frequently it even seizes individuals of its own kind. In such casesitis always | Infusoria, and never the Rotatoria, although the latter often abound in waters which the Didinium inhabits. It appears, moreover, to have a marked predilection for certain species; and so it happens that the huge and inoffensive Paramecium aurelia is almost always its choice by preference among the animalcula that inhabit the same liquid.* * The Didinium, Balbiani tells us, never attacks the Parmacium bursaria, which is distinguishable from the P. aurelzéa by its green coloration. 54 THE -PSVCHFCALTLT EEL: The prehension of food by the Didinium exhibits interesting aspects, which have not as yet been ob- served in any other Infusory. M. Balbiani, in his first observations, had often been surprised at seeing animalcula that the Didinium had passed by without touching, suddenly stop as if violently paralyzed; whereupon our carnivorous specimen straightway ap- proached and seized them with seeming facility. More careful examination of the Didinium’s actions ~ soon furnished the key to this enigma. If, while swiftly turning in the water, the Didinium happens into the neighborhood of an animalculum, say a Para- mecium, which it is going to capture, it begins by casting at it a quantity of bacillary corpuscules which constitute its pharyngeal armature. The Parmecium immediately stops swimming, and shows no other sign of vitality than feebly to beat the water with its vibratile cilia; on every side of it the darts lie scat- tered that were used to strike it. Its enemy then ap- proaches: and quickly thrusts forth from its mouth an organ shaped like a tongue, relatively long and re- sembling a transparent cylindrical rod; the free, ex- tended extremity of this rod it fastens upon some part of the Paramecium’s body. The latter is then grad- ually brought near by the recession of this tongue- shaped organ towards the buccal aperture of the Didinium, which opens wide, assuming the shape of a vast funnel in which the prey is swallowed up.* Up to this point we have paid little attention to movements of defence and of flight: Upon this sub- ject a few words will suffice. When vorticels are alarmed, they are seen to contract forcibly their pedi- * Archives de zoologie expérimentale, 1873, Vol. Il, p. 363. Observations sur le Diditnium nasutum, by E. G. Balbiani. a OF MICRO-ORGANISMS. aS cle, which in a state of rest stays extended. Infusoria placed in a preparation where they are at their ease, swim quietly about; if any sharp excitation disturb them, they accelerate their pace; those armed with a rigid bristle at the posterior extremity, rush precipi- tately onward whenever another Infusory chances to touch that tactile appendage. The unaggressive Par- mecia, when attacked, endeavor to escape, but are also able to defend themselves by means of the tricho- cysts with which their ectosarc is armed. IV. Unicellular organisms do not all live in a detached state; a large number of species are found grouped together in colonies; the initial basis of these agglom- erations is always a mother cell, the offspring of which instead of dispersing to live at large, remain aggluti- nated to-one another. Ehrenberg had believed that in certain species (especially in the case of the 4ntho- physa vegetans, an aggregation of minute monads growing asa sort of bush) the colony was created by the union of minute organisms that originally lived at large; but observation has shown that his theory was incorrect. It may be laid down as a general rule that every colony of monocellular animals or vegetables spring from the divisions of a single cellule. The cellules of one and the same colony, therefore, are always sister cellules, and the colony represents a family in miniature. A leading instance of a colony wholly temporary, is found in those organisms the cuticle of which does not take part in the phenomena attending the division of the protoplasm. In this case, the protoplasm beneath the envelope alone divides; the segments resulting 56 THE PSY CHIL Ce ALS therefrom are often numerous, and it is not until the plasma has finished dividing that the maternal cuticle is destroyed and that the segments separate to live abroad in a detached state. Up to that time they re- main bound together. It is thus seen that the existence of this minute colony is a transient phenomenon, which lasts only during the time necessary for the division of the ma- ternal body. These phenomena have been noticed among many of the Flagellates. What appears surpris- ing is, that the maternal cellule, although continuing to divide beneath the envelope, keeps on moving about in the water by means of its own flagellum as if still constituting only a single animal. The reason of this is that one of the segments into which the plasm is divided and which is situated in the anterior part of the mother-cellule,.remains connected with the flagel- lum and takes charge of its movements. This seg- ment (like an individual distinct in itself) alone guides the bark that carries its sisters. And so, although this diminutive colony is asa rule but short-lived, a division of labor has been effected among its mem- bers; the anterior segment is alone entrusted with the office of locomotion. | The colony has a duration less ephemeral in the case of the Gontum pectorale, a Volvocine known in our fresh waters. It is formed by the aggregation of sixteen individuals which remain detached but ad- here laterally to one another. The colony is de- veloped in one way only: it is in the form of a minute rectangular plate of a beautiful green color. In the case of the Pandorina, the colony assumes the form of a minute sphere; it is composed of sixteen, or as many as thirty-two individuals, joined together beneath a OF MICRO-ORGANISMS. 57 stout envelope; each member remains free in action, and projects its two flagella through the cuticle. With the Ludoryna elegans, the colony is modeled upon nearly the same plan excepting that it is com- posed of thirty-two individuals and that the latter, placed beneath the same cuticle at equal distances apart, do not touch one another. In the genus Volvox, colonies are found of which the structure is very complicated. Such are the great green balls formed by the aggregation of diminutive organisms, which form the surface of the sphere, and -are joined together by their envelopes; they have each two flagella, which pass through the enclosing mem- brane and swing unimpeded on the outside; the en- velopes, each tightly holding the other, form hexag- onal figures exactly like the cells of a honeycomb. Each Volvox is at liberty within its own envelope; but it projects protoplasmic extensions which pass through its cuticle and place it in communication with its neighbor. It is probable that these proto- plasmic filaments act like so many telegraphic threads to eStablish a network of communication among all the individuals of the same colony; it is necessary, in fact, that these diminutive organisms be in communi- cation with each other in order that their flagella may move in unison and that the entire colony may act as a unit and in obedience to a single impulse. The number of micro-organisms constituting a Volvox colony is quite considerable: as many as 12,000 have been counted. It was upon analogous phenomena that Gruber based the existence of a diffused nervous system in the Stentors. The same line of reasoning may be fol- lowed in the case of the Volvox. Since unanimity of — 58 LAE OES VCH GILLES movement is demonstrable among twelve thousand micro-organisms constituting a colony, it must be in- ferred that their movements are regulated by the action of a diffused nervous system present in the protoplasm. This conclusion is all the more inter- esting from the fact that these Volvox are vegetable micro-organisms. In the dicecian Volvox, the female cellules and the - nale cellules are joined together by themselves in sep- arate colonies. When the time of fecundation arrives, the male cellules or antherozoids scatter and proceed to conjugate with the female cellules. The colony which bears the female cellules also contains neutral cellules which are not designed for fecundation; the latter simply perform a locomotive function; equipped with one eye and two flagella, they are intended to move the great colonial ball: they are the oarsmen of the colony. The Volvox, male, female, and neutral, all seek the light, whether solar or artificial, and settle near the surface of the water. As soon as the female colonies have been fecundated, the odspores change their color: they turn from green to an orange yellow. At this point, the colony is seen to draw away from the light and to disappear from the surface of the water. This change of position is effected by means of the vibratile cilia with which each neutral cell is furnished and which project beyond the gelatinous sphere; now, as no change of color or form is noticed in the neutral cells after fecundation, it may be asked from what cause they flee from the light which they formerly sought. Colonies of Proto-organisms formed by the division of a mother cell of which the segments remain united, are not entirely without analogy with a pluricellular OF MICRO-ORGANISMS. 59 organism which likewise springs from a single cell called the egg, and the resultant divisions of which do not separate. : The colony constitutes in a way a first step towards the physiological constitution of a pluricellular organ- ism; it serves to fix a stage of transition in the animal kingdom, between Protozoaand Metazoa. A fact which strengthens this analogy is, that certain colonies, as the Synura uvella and the Uroglena volvox, can divide into two other colonies; strangulation acts upon the mass just as if upon a pluricellular organism. This curious observation was made by Stein and Biitschli. Nevertheless, an essential difference still separates the Metazoa and the Protozoan colonies, even when in these colonies a division of function has been established among several individual groups. The physiological differentiation brought about in these Protozoan colonies is the result of amechanism which differs in every respect from that by -which it is effected in the case of the Metazoans. In the latter instance the differentiation results from the division of the embryo into germinative folia each of which is the origin of a separate group of organs. At a certain stage of development, the superposition of these folia - gives rise to the formation of a gastruda; the gastrula is formed by two folia joined together, representing a pouch open to the outside; it is characteristic of Met- azoans, the Protozoan never reaching this stage. Cer- tain colonies observed by Heckel, the Wagosphera plan- w/a for example, and the volvox, of which we have before spoken, appear in the form of a sphere; they suggest an anterior stage of development to which the name of morula or of blastula has been given; but they do not get beyond this stage. 60 THE PSYCHIC LIFE We have now considered assemblages of organ- isms which live joined together like the Gonium and sometimes united by a material band like the Volvox, | “where the individuals are erouped together under one and the same cuticle. Voluntary and free combi- nations are much more rarely met with; nevertheless © cases occur. There exist organisms which lead a life of habitual isolation but which understand how to unite © for the purpose of attacking prey at the desired © time, thus profiting by the superiority which numbers give. The Bodo caudatus is a voracious Flagellate pos- sessed of extraordinary audacity; it combines in troops to attack animalcula one hundred times as large as itself, as the Colpods for instance, which are veritable giants when placed alongside of the Bodo. Likea horse attacked by a pack of wolves, the Colpod is soon ren- dered powerless; twenty, thirty, forty odos throw themselves upon him, eviscerate and devour him com- pletely (Stein). All these facts are of primary importance and in- terest, but it is plain that their interpretation presents difficulties. It may be asked whether the Bodos com- bine designedly in groups of ten or twenty, understand- ing that they are more powerful when united than when divided. But it is more probable that voluntary combinations for purposes of attack do not take place among these organisms; that would be to grant them a high mental capacity. We may more readily admit that the meeting of a number of Bodos happens by chance; when one of them begins an attack upon a Colpod, the other animalcula lurking in the vicinity dash into tne combat to profit by a favorable opportu- nity: OF MICRO-ORGANISMS. 61 v. It is difficult in the extreme to mark out the lines of a psychology of Proto-organisms from data so in- complete as those we have just collected. We shall content ourselves with a few brief considerations. The apparent result of our investigations up to this point is, that the greater number of movements and actions observed in Micro-organisms are adrect re- sponses to excitations emanating from the medium in which they live. Itis the condition of the medium that, to all appearance, rigidly determines the character and manner of their activity; in a word, they exhibit no marks of pre-adaptation. But it will not do to let the matter rest with this general survey of the subject; we shall have to examine more closely each detail of these reflex actions of.adap- tation, beginning with the sensory phase and ending with the motory phase. Analysis discloses that sev- eral determining elements ‘may be distinguished in these phenomena; they are: 1. The perception of the external object; 2. The choice made between a number of objects; 3. The perception of their position in space; 4. Movements calculated, either to approach the body and seize it, or to flee from it. Weare not ina position to determine whether; these various acts are accompanied by consciousness or whether they follow as simple physiological processes. This question we are obliged, for the present, to forego. 1. The perception of an external body. Among the lowest forms, it appears that perception is always the result of a direct irritation produced by contact of the external body with the protoplasm of the animalcule. This is what takes place, to all appearance, among the 62 LAE ESVCH iGo Pe Amoeba; for these organisms, the condition necessary to the perception of a solid particle is contact with it. A step forward has been effected in those organisms that are able to perceive external objects by contact from a distance, as is observed for instance in the Actinophrys, which perceives all bodies that chance to touch its long filamentous pseudopods; yet, in this in- stance, the pseudopod merely acts the part of an ex- tended tactile organ. The vibratile cilia, and _ still ' more the long lash of the Mastigophores, enable the animal to discern the presence of contiguous particles at acertain distance from its body, by the pressure exerted upon their appendages. It is not known whether there are many animalcula that perceive the presence of nutriment from a distance and without coming in direct contact with it; it appears, however, that this is the case with the Didinium which shatters its prey from a distance and without touching it. 2. Choice. We have seen that Micro-organisms do not absorb indiscriminately every solid particle they meet. They exercise a choice. Among the lower spe- cies, the choice is in the lowest degree rudimentary; the organism restricts itself to a discrimination of mineral particles, sand for example, from organic sub- Stances; it rejects the former and absorbs the latter, Among the higher animalcula the choice is more in- telligent. There are Infusoria that feed only upon plants and animals. There are also those which feed exclusively upon one species. , This exercise of choice is one of the most incom- prehensible of phenomena; it is exceedingly difficult to explain it without resort to anthropomorphism. If we hold to what observation directly teaches us, the choice may be said to consist in the following acts: OF MICRO-ORGANISMS, — 63 when aie era eile perceives certain kinds of sub- stances and particularly those substances which serve it as customary food, it invariably goes through the same movement, which consists of an act of prehension; when the substance touched, seen, or collided with, as the case may be, is of another kind, the Micro-or- ganism does not.go through this act. Such is the phenomenon; as to the explanation of the same, we are unable to give one. According to M. E. Maupas, if certain Infusoria feed exclusively upon a certain species, it is because their buccal apparatus, or organ of prehension, makes it impossible for them to feed upon different species which possess different tegumentary envelopes. The question is to ascertain whether this explanation is applicable only in certain cases, as appears very prob- able to us, or whether, on the other hand, it is of com- plete and universal applicability. We confess that the hypothesis of M. Maupas does not explain to us why a hunter Infusory that throws trichocysts, like the Didinium, attacks the Paramecium aurelia and not the Paramecium bursaria. It is possible that certain species attract the or- ganisms which feed upon them, by means of a phys- ical or chemical excitation. The researches of Prof. Pfeffer, of the Tubingen Botanical Institute, lend a certain confirmation to this hypothesis. 3 3. Calculation of the position occupied by the exter- nal body. It isa universal fact that Micro-organisms not only perceive external bodies, but that they also indicate, by their movements, an exact knowledge of the position occupied by these bodies. It might be said that they invariably possess a sense of position in 64 DAL OPS VGHLCCLA EL space. The possession of this sense is absolutely in- dispensable to them, for it does not suffice them to know of the presence of an exterior body in order to approach it and seize it; they must furthermore know its position, so as to direct their movements accord- ingly. The simplest form of a sense of localization is met with in the Amceba, which, when it closes about a nu- - tritive particle, always emits its pseudopods at pre- cisely that part of its body where the foreign substance caused theirritation. The most complicated instance of localization is met within the Didinium, which we have so often cited; the Dzdintum knows precisely the po- sition of the prey it follows, for it takes aim at the ob- ject of its pursuit like a marksman, and transpierces it with its nettle-like darts. Between these two species, we find all the intermediate instances of a localization of perceptions. However, doubts exist upon the question as to - whether Proto-organisms know the direction and dis- tance of external bodies, or whether they only succeed in getting at them after a series of tentative move- ments. ‘The observations which we have collated do not solve the question. 4. Motory phase.-—We now pass to the motory phase. The movements made by Micro-organisms as if in response to an excitation, are not in mogt in- stances simple reflex motions; they are movements adapted to an end. Wecannot repeat it too much: these movements are not explained by the simple phe- nomenon of cellular irritability. In the very first instance, they vary according to the excitation; a given excitation produces a corre- sponding motory response; a body situated at the right — OF MICRO-ORGANISMS. 65 * does not bring about the same movement that a body situated at the left does; a particle of the nutritive sort does not provoke the same course of action that a particle of a different sort does. All this implies that associations have been established in the proto- plasm between certain excitations. and certain move- ments. The explanation of the physical nature of these*association appears to us totally impossible. The quite ingenious ideas broached by Spencer upon the lines of least resistance offered by the com- misural fibres cannot be applied here, since everything takes place in a single cell. What would be necessary to explain is how and in consequence of what mechan- ism of structure one form of molecular movement, cor- responding to a given excitation, is followed by a cer- tain other form of molecular movement correspond- ing to an act likewise determined. VI. FECUNDATION. We now enter upon a subject fraught with obscu- rity. We shall limit our investigations to ciliated In- fusoria, as it is among these species that fecundation and the psychical phenomena attendant thereon have been best observed. Ehrenberg had established by his authority the pre- vailing opinion in science that copulation never takes place among Infusoria, and that all facts observed by early writers as connected therewith are to be re- garded as phenomena of longitudinal fissiparity. This erroneous idea prevailed unquestioned until 1858, when M. Balbiani addressed a communication to the Academy of Sciences, wherein he showed that sexual 66 THE OPS VOHEC LILLE reproduction, preceded by copulation, zs found among Infusoria. Before entering upon a description of the changes that take place in the nucleus and nucleole of Infuso- ria in coition, we shall briefly sketch the course of psychical phenomena through which the ciliated Infu- soria pass when making ready for copulation. We shall follow in the footsteps of M. Batbiani, freely using his descriptions, the exactitude of which has since been confirmed by Gruber. To appreciate fully the significance of the facts to be adduced herewith, we must recall to mind that throughout the entire animal kingdom the act of sex- ual coition is invariably preceded by an introductory manifestation of psychical activity, which may last for quite an extended length of time. } The female, when pursued by the male, seems to be animated by two conflicting desires—that of yield- ing to the male and ‘that of repelling his approaches. This show of unwillingness, which is but temporary and more seeming than real, has the effect of inciting the male to attempt an exhibition of powers calculated to captivate the female. According to M. Espinas, who has thoroughly studied this subject, there are five classes of phenomena which assist in preparing the way for sexual union: firstly, provocative contact, the lowest of all these phenomena—that is, the one which ‘most approximates to the physiological order; sec- ondly, odor; thirdly, color and form; fourthly, noise and sound; fifthly, play, or every variety of move- ment. It appears to us that almost all manifestations of love in human beings themselves could be classi- fied into these five categories. Among the simplest forms of life we meet with in- OF MICRO-ORGANISMS. 67 cipient traces of such esthetical manifestations point- ing towards the preparation of two animals for sexual intercourse. ‘Tt 1s currous,’” remarks M. Balbiani, “to find among these organisms which all zodlogists, by reason of their diminutive size and extreme simplicity of structure, have placed at the remotest limit of the animal kingdom, acts that mark the existence of phenomena analogous to those by which the sexual instinct is ex- hibited in a large number of Metazoans. Upon the approach of the period for propagation, the Paramecia come in from all points of the fluid and assemble like - little whitish clouds in more or less numerous groups about the objects that float upon the surface of the water, or adhere to the side of the vessel containing the tiny artificial sea in which the animalcula are held captive. Intense excitement, which the need of food does not suffice to explain, prevails in each of these groups; a higher instinct appears to dominate all these tiny organisms; they seek each other’s company, chase each other about, feel here and there with their cilia, adhere for a moment or so in an attitude of sexual co- ition, and then retire, soon to begin anew. When these minute assemblages are dispersed by shaking the liquid, they quickly form again at other points..- These singular antics wherewith animalcula appear to incite each other mutually to copulation often continue for several days before the latter act is defin- itely effected. ‘“¢ Other Infusoria, particularly the Spirostomes, seek the deep spots of the liquid, or bury themselves in the oozy sediment of the bottom, not to come forth again until they have separated. The Stentors have differ- ent habits. They are affixed by their pedicles to sub- 68 PALE PSVOH LOLI L SE: merged vegetable patches, which they often cover like small, closely-mown lawns, of a green, brown, or blue color, according to the species; they turn the forward part of their bodies, which is elongated in the shape of a trumpet, about in all directions, and seek to unite with each other by the broadened extremity which corresponds to the bell of the trumpet.” Among the numerous species forming part of the group of Oxytrichine, the act of coition likewise ex- hibits certain interesting preliminaries. . The two individuals, whose bodies are generally very much flattened, and of which the lower sides are provided with cilia at times strongly developed, superpose them- selves upon each other on the ventral side and mutu- ally entangle the cilia which cover that region, while with their cornicles, or anterior tentacles, they touch repeatedly the different parts of each other’s bodies. These introductory moves frequently last for several hours before copulation begins. As regards the act of copulation itself, it too is of exceeding interest to the psychologist, who can ad- mire the precision with which the two individuals as- sume the attitude necessary for fecundation. During conjugation the two ciliated Infusoria are ‘always joined together at the aperture which forms the mouth. It has been thought that this aperture must play the part of a sexual orifice through which the two animalcula in copulation effected the exchange of reproductive matter; it has been suggested, more- over, that an especial sexual orifice was present, quite close to the mouth; but these questions of structure are still doubtful. ; The attitude of these organisms during copulation OF MICRO-ORGANISMS. 69 varies according to the position of the mouth which in certain groups is lateral and in others terminal. The greater number of species have a lateral mouth. To this class belong the Paramecia; these Infusoria, in which the buccal fosse lies at the bottom of a deep excavation made in the ventral face, cover each other over the whole extent of this face, exuding a gluti- nous substance which causes them to adhere in this _ position; the two mouths then lie exactly upon each other. Copulation lasts from twenty-four to thirty-six hours with the Paramectum aurelia; it lasts several days (five or six) with the Paramecium bursaria. Among the Oxytrichine, the two animals in conjuga- tion blend together at an important part of their per- sons in a very intimate fashion. We next arrive to the second group of Infusoria, which show a terminal mouth; of this type we have had a specimen in the Didinium nasutum, the curious hunter Infusory; we may further mention the Coleps, the Nassula, the Prorodon. The two organisms, in this case, do not embrace laterally, they take a posi- tion end to end, connected by their anterior extrem1- ties, mouth opposite to mouth; then, little by little, while still joined at the buccal extremity, they shift about until they meet length to length. We shall mention particularly, but briefly, the cu- rious phenomena that accompany fecundation among the Vorticels. Even more than in the instances just cited do these phenomena resemble the process of fecun- dation in higher animals, for in this instance fecunda- tion is effected between two differentiated individuals, one of which acts as a male element and the other as a female element. The Vorticels are colonies of In- fusoria in which are found sedentary individuals, 70 THE PSYCHIC LALL having the shape of minute jugs, and also detached individuals called Microgonidia, which are formed by repeated divisions upon the colonial tree. These Microgonidia have exactly the same mode of locomotion as the spermatozoids. Engelmann * has followed their movements. He has seen them swim- ming about turning upon their axis for five or six minutes; then, having come into the vicinity of a Vor- ticel, they abruptly change their manner of movement, capering about the latter like a butterfly flitting about a flower, touching it, retreating, and then approaching it again and apparently feeling of it; at last, after having visited the others near by, they return to the first one and fasten themselves upon its surface. The coition is not effected without a certain show of re- sistance on the part of the Vorticel. It hastily con- tracts the peduncle to which it is attached, at every touch of the Microgonidium, while the latter in order to prevent itself from being thrown back by these rapid shocks and in order to be always close to the individual with which it wishes to unite, fastens itself by an extremely fine filament to the style of the Vor- ticel; thus attached and drawn along with the move- ments of the latter, it finally succeeds in effecting a . junction with it and in penetrating into its body.+ It is now time to describe the material phenomena that take place in the interior of the two Infusoria, and which constitute the material act of fecundation. The psychical manifestations which we have just noted and which so strikingly resemble the manifestations accompanying the copulative act in higher animals, ° are of themselves sufficient evidence ‘that this conju- gation is a sexual union. * Arch. de Zodlog. expérimentale, Vol. V, 1876. + Fournal de Micrographie, 1882, p. 241. OF MICRO-ORGANISMS. 71 The material changes effected inside the bodies of Infusoria in copulation do not extend to all their or- gans; the main mass of the body, the protoplasm, plays but a secondary vé/e in the matter; the change appears to be effected exclusively in the nucleus and the nu- cleole. Let us further state that, so far as is known, these changes are never effected apart from coition and be- fore the Infusoria actually embrace; copulation sets in every time, apparently, that these animals, under particularly favorable conditions, have actively repro- duced by fission. Fissiparity is then seen to cease and conjugation appears. We have not the time to sketch the history of this important question of physiology, interesting as it may be. It will be enough to recapitulate what we actu- ally know upon the subject, taking as our guide sub- stantially the views of M. Balbiani who, as is known, was the first scientist to study the physical phenome- na connected with fecundation among Infusoria. The divergencies between his observations and those of an- other eminent investigator, M. Biitschli, extend in re- ality only to points of detail. Let us first mark the modifications that take place within the Chzlodon cucudlus during conjugation. Each of the two Infusoria in copulation possesses a nucleus (endoplast, main nucleus) and, close beside this nu- cleus, an organ considerably smaller, a nucleole, or attendant nucleus, or latent nucleus (endoplastule, accessory nucleus); this minute body must not be mis- taken_ for the nucleole that is often found in the inte- rior of the nucleus among many Micro-organisms and in cellules; it has a function entirely different. Of these two elements, the nucleus plays an al- 72 THE PSYCH CLLEE -~ most negative part in the act of fecundation. It as- sumes irregular outlines and becomes rumpled, while its contents collect in detached masses of various sizes: it grows clear by degrees and is finally absorbed. It disappears, accordingly, by a phenomenon of regres- sion and without dividing. Fecundation aims to replace this wasted element by a nucleus of fresh formation. The latter is pro- duced at the cost of the little body we have described by the name of attendant nucleus or latent nucleus. The attendant nucleus does not act in making upa main nucleus in the cellule of which it is a part; it finds its way into the body of the other animal and it is in this new cellule that it is destined to perform the function of a nucleus. In the Chilodon cucullulus, the attendant nucleus divides into two striated capsules, never more. These two capsules grow to unequal sizes; the largest attains a size of forty thousandths of a millimetre; it is this one that forms the new nucleus of the Chilodon. The second capsule shrinks and becomes compressed; it takes its place beside the first one and constitutes the new attendant nucleus. To the study of this type of fecundation we may limit our attention; it is the simplest of all, and other forms may be comprebended within it without much difficulty. What complicates the process in the other species is principally the successive modifications through which the old nucleus passes before suffering absorption. In the Stentor ceruleusthe nucleus has the shape of a long chaplet or string of beads; at the moment of fecundation the beads of the chaplet break apart and spread in the protoplasm where they finally become absorbéd. Among the Paramecia the phe- OF MICRO-ORGANISMS. 73 nomenon is still different: the nucleus, at first massed together in a cluster, lengthens out into a very long string, which breaks; and the pieces becoming scat- tered about in the protoplasm, are absorbed. We find that fecundation in every instance intro- duces the dispersion and disappearance of the old nu- | _ cleus and that the latter is replaced by a new nucleus resulting from the transformation of the attendant nu- cleus that proceeded from the other organism. The various modifications presented by this atten- dant nucleus likewise contribute in great measure to the complexity of the phenomenon. We have seen that in the Chilodon the attendant nucleus breaks into two globules, of which one goes to form the new nu- cleus and the other the new attendant nucleus. Mat- ters take a different course in the Paramecia. In the Paramecium bursaria, for instance, the attendant nu- cleus divides into two and then into four capsules; one of these capsules suffers absorption, a second one becomes the attendant nucleus, and the two others coalesce with what remains of the old nucleus to form the nucleus proper. In the Paramecium aurelia the di- vision is made into eight capsules; three are cast out, and of the five left four are meant to form the new main nucleus; in reality, each Paramecium segmen- tates first into two and then into four divisions, and each of these four individuals takes one of the capsules. The fifth capsule is designed to form the attendant nucleuses of these four organisms; it divides, accord- ingly, into two and then into four parts; that is to say, into as many parts as the body of the animal divided, There is no question in our mind but that conjuga- tion in this case is a sexual phenomenon. A circum- stance that at the outset confirms this is the peculiar » — 74 THE PSYGHLGCLT LL manceuvering the animalcula go through before aban- doning themselves to copulation; the movements they execute admit of exact comparison with the actions attendant upon copulation among higher animals. But we shall recur further on to the physiological signifi- cance of conjugation, when we shall endeavor to ex- plain, according to the most recent investigations, the function of the nucleus in the cellule. | The question may be asked, what is the starting- point, the provocative of these sexual phenomena, the cause that sets them inplay. Btitschli justly thinks, that conjugation is determined by internal causes; in fact, it takes place directly after very active periods of spontaneous division, as Balbiani has shown. When we bear in mind that the object of conjugation is to replace the old nucleus which has become wasted and worn out, we may conjecture with some degree of like- lihood that the physiological condition of the nucleus constitutes the sexual excitant that causes the Infuso- ria to copulate. However that may be, a curious observation witn the Paramecium aurelia has made us acquainted with one of the structural conditions of the sexual instinct in that Infusory. Fora long time J. Miller had pointed to the presence of filaments in the nucleus and even nucleolus of Paramecia, that had the appearance of spermatozoids. Observations to the same effect have increased since then, and it is now known that the filaments are Schizomycetes, parasitic Bacilli, which find their way into the nucleus and nucleolus, and mul- tiply, after their customary mode of segmentation, by disarticulation. Balbiani has definitely determined the nature of these filaments by morphological and micro-chemical methods; he has found out, among ‘OF MICRO-ORGANISMS. 75 other things, that the filaments do not dissolve in strongly concentrated alkaline solutions; and it is known that Bacteria exhibit this peculiar attribute of offering a great resistance to destructive agents. In the nucleus which they have penetrated, these parasites induce a pathological condition that results in destroying every manifestation of the sexual in- stinct in this Infusory. Among a swarm of animals of this species that are in copulation, single individuals are found that show a nucleus and nucleolus com- completely charged with Bacteria; sometimes these organs suffer an enormous dilatation, the nucleus be- coming nothing more than an enveloping membrane which is filled like a huge pouch with parasites. The animal continues to live, but it no longer attempts to copulate. VII. It is not our intention to make a full and complete study of fecundation in higher animals and plants; there is but one phase of that phenomenon that can enter into a general study of Micro-organisms, and that is the history of the sexual elements, of their form, their movements, and lastly their copulation. We shall describe animal fecundation first, and plant fecundation afterwards; regarding these phe- nomena particularly from a psychological standpoint. Among metazoans, fecundation may be divided into two distinct acts. The first, and most apparent, consists of the union of the two individuals; of this we shall not have to speak here; it is a phenomenon that lies outside the limits of our investigations. The sec- ond, more deep-seated, consists in the phenomena 76 PHEOIPSY CHIC LLIFL that take place, after copulation, between the sperma- tozoid and the ovule. There are numerous reasons for comprehending a study of the generative elements within a general in- vestigation into the nature of Micro-organisms. In the very first place, it must be taken into ac- count, that these two elements are represented in ani- mals by a single cell. The ovule appears as a minute microscopic sphere enclosed by an envelope (vitelline membrane); it is formed of a mass of granulous protoplasm (vitellus) containing a nucleus (germinative vesicle) and one-or many nucleoli (germinative spot). The spermatozoids, in vertebrates, have quite a different aspect: they are filaments of varying lengths, having a distended part, or head, and a tapering, attenuated part, or tail. The resemblance that spermatozoids bear to Pro- tista, at first caused them to be regarded as animals living a parasitic life in the spermatic fluid. Ehren- berg classed them among the polygastric Infusoria. Keelliker and Lallemand were the first to reject this notion and the first to regard spermatozoids as ele- mental parts of living tissues, having the morpho- logical value of a cellule. They are now likened to de- tached cellular elements, such as blood-globules. Whatever form they assume, the sexual elements live as minute organisms independent of the individ- ual from which they originated. This circumstance is particularly remarkable in thecase of the male element, the spermatozoid, which retains its vitality for a cer- tain space of time after its expulsion. The length of this period varies with the different species. Whereas the spermatozoids thrown from a trout loseall motion in the water after the expiration of a few seconds, . OF MICRO-ORGANISMS. 97 those of the bee, in the seminal reservoir of the fe- male, remain alive for several years. The seminal ele- ments of mammifers live for quite some time in the genital passages of the female. Balbiani has found living spermatozoids in the ducts of a she-rabbit twenty hours after coition. Ed. van Beneden, Benecke, Eimer, Fries, have observed that the sperm retains its prop- erties in the uterus of bats for several months. Another remarkable circumstance is, that the cop- ulation of the two sexual elements is not without anal- ogy to the copulation of the two animals from which they originated. The spermatozoid and the ovule, to some extent, repeat on a small scale what the two in- dividuals perform in their larger sphere. Thus, it is the spermatozoid that, in its capacity of male element, .~goes in quest of the female. It possesses, in view of the journeys it has to make, organs of locomotion that are lacking in the female and are useless to it. The spermatozoid of man and of a great number of mam- mifers is equipped with a long tail, the end of which describes a circular conical movement, which together with its rotation about its axis, determines the forward motion of the spermatozoid. The same mode of pro- gression is seen in the zodspores of Algz and in Masti- gophores, which are armed with flagella; the move- ments of the spermatozoid have been not improperly compared to those of a Flagellate. Other spermatozoids like those of the Triton and Axolotl are provided with a different kind of locomo tive apparatus; it consists of an undulatory membrane that acts like a real fin; the spermatozoid moves for- ward without turning about on its axis. There has been much discussion as to the nature of the forces that account for the movements of the 78 TILE EOS VC LLC Le] Lee fecundative elements. The early investigators that concerned themselves with the study of animalcula, naturally attributed to them spontaneous and volun- tary movement. Since the spermatozoid has been re- garded as nothing else than an histological element, endosmotic, hygroscopic and like actions have been accepted in explanation. M. Balbiani, from whom we have taken the foregoing details, declares that expla- nations of this character are none at all; for, upon ul- timate analysis, all kinds of motion may be reduced to a chemical or physical action—sarcodic or ciliary movement just as much as voluntary movement. ‘“ For my part,” our scientist adds, “I believe that the sper- matozoids do not move about blindly but that they act in obedience to a kind of internal impulsion, to a sort of volition which directs them towards a definite object.”’* The experiments of M. Balbiani have shown that with weak solutions of ether and chloroform the movements of the spermatozoids may be moder td and made to cease so slowly that the latter ai ;et-ahie ° to fecundate the ovules. 2 In fine, the spermatic element, ? gigiog itself toward the ovule to be fecundated, 1: ws y thes same sexual instinct that gies the’ @"rentrs ism towards its female. | In the higher animals, the movements of the spermatozoid that is endeavoring to reach the fe- male exhibit a peculiar character, which it is im- portant to emphasize: these movements do not ap- pear to be directly provoked by an exterior object, as those of micro-organisms are; the spermatozoid en- deavors to reach an ovule which is frequently situated a great distance away; this is the case particularly * La Génération des Vertébrés, p. 159. ~ OF MICRO-ORGANISMS. 79 with animals that fecundate internally, with birds and mammifers. The place of fecundation is still imper- fectly known. Coste at one time accepted the theory that the spermatozoid and ovule met in the ovary. Fecundation probably takes place in the fore part of the oviduct. It has little to do with our purpose, how- ever, to solve this delicate question precisely. A fact that is important to mention in a genera] way is the length of road the spermatozoid has to traverse before coming up with the ovule. Let us now follow the spermatozoid in its journey -to the ovule. It is known that the road it has to tra- verse 1s, in certain instances, extremely long. Thus, in the hen the oviduct measures 60 centimeters, and in large mammifers the passages have a length of from 25 to 30 centimeters. We might ask ourselves how such frail and minute creatures come by a power of locomotion great enough to enable them to traverse .so long a path. But observation discloses the fact that traoy are able to overcome obstacles quite out of proportic their size. Henle has seen spermato- Zoids Gf 5: g with them masses of crystals ten timesn of ti. 1 themselves, without appreciably les- selysion-neir ,.,eed. F. A. Pouchet has seen them carry bunches of from eight to ten blood-globules. M. Balbiani has attested the same fact. These globules, which have fastened themselves about the head of the spermatozoid, have each a volume double that of the head. Now, according to Welcker, the weight of a globule of human blood is 0.00008 of a milligramme: allowing that the spermatozoid has the same weight, we may then say that it is able to carry burdens four or five times heavier than itself. | The length of road traversed is not the only remark- 80 LHL PD SVGHIC SLILE able circumstance here; there are also involutions and intricacies in the path to be followed in reaching the ovule. In this connection an interesting observation has been made upon the silk-worm. “ At the moment of conjugation the male deposits its seminal fluid in a special sac, the copulatory sac. The day following, this sac, which was distended by the sperm, is com- pletely flaccid, and nearly all the spermatozoids have traveled out into another sac, which opens into the oviduct opposite the first one, and there they wait to fecundate the ovules as they pass by. Now, the walls of the copulatory sac have no contractile power, and the passage of the spermatozoids from one sac into the other can be attributed only to a spontaneous movement. Further, a fact that well seems to verify this, is, that there still remains in the copulatory sac. a few misformed seminal elements, deprived of the power of locomotion.” * Let us now note what happens at the moment when spermatozoid and ovule come in contact with one another. The successive phenomena then taking place have been carefully studied by Fol in his work upon the star-fish (4sterias glactalis). The ovule has no enveloping membrane; it it is covered about only by a mucous layer, soft and flaky. The spermatozoids come up in great numbers and push forward into this layer; at this point they are all brought to a halt and become entangled among each other with the excep- tion of one, which, more speedy in its movements, out- strips the others and arrives within a short distance of the surface of the vitellus (or protoplasm of the ovule). At that moment, and before any contact whatever, there results a curious phenomenon of attraction between the * Balbiani, Comptes Rendus del’ Acad. des Sciences, 1869. OF MICRO-ORGANISMS. 81 ovule and the spermatozoid; the peripheral substance of the ovule is seen to lift itself up in front of the sper- matazoid in the shape of a minute protuberance; this protuberance, at first, has a rounded shape, then it grows thinner and forms a point which advances to- wards the spermatozoid; this point is called the cone of attraction (see Fig. 8). The head of the spermatozoid fastens itself upon the cone, which seems to draw it into its in- terior. The tail of the spermatozoid does not appear to enter into the interior of v3, the ovule and take part in the process of Tebola ge fecundation, which consists simply in the Fig. §—A small fusion of the head of the spermatozoid portionoftheovule , of a star-fish (As¢e- With the nucleus of the cellule. Posting tis fone. As soon as the head of the spermato- tion of the cone of : : attraction. (Ac- Zoid has penetrated into the ovule, the cording to Fol.) : 4 latter enwraps itself in an envelope, to protect itself against the other male elements. It ap- pears, in fact, to be well settled that the penetration into the vitellus of several spermatozoids marks the beginning of an adverse change: the subsequent seg- mentation of the ovule is irregular, and development ceases. The membrane in which the fecundated ovule of the Asterias glacialis infolds itself, is formed bya con- densation of the peripheral layer of the vitellus; the condensation starts from about the point where the Spermatozoid penetrated, and gradually spreads over ’ the whole surface of the ovule; the formation of this . protective membrane is so rapidly effected, that access to the ovule is barred against spermatozoids who might be only a few seconds behind the first one. Sexual selection, then, acts among spermatozoids 0. se PR a er * a.0°e 9 C eee ANI . * es 82 TALE SE SY CLL Ce LILLE just as among all animals; it is the most agile and the stoutest spermatozoid that first penetrates the ovule and effects fecundation. The laws of selection, thor- oughly developed by Darwin, do not only apply to in- dividuals; they apply also to sexual elements. We are unable to follow the successive modifica- tions suffered by the head of the spermatozoid after its entrance into the ovule; we may state simply, that the head presents the appearance of a radiate figure, of a diminutive sun advancing towards the female nu- cleus. At the same moment, the female nucleus ap- pears affected and puts itself in motion towards the spermatic nucleus. The two nuclei soon come almost within contact, and it is in particular the female nu- cleus that then plays the active part. It is disturbed. by incessant movements and every moment changes its form; it thrusts out prolongations towards the male nucleus, and one of these prolongations fastens itself upon the latter, presenting at the end a minute de- pression in the shape of a cup, which receives the male nucleus; and the two nuclei, while executing active movements, fuse into one another. In this manner the first nucleus of segmentation is created. Selenka has furnished interesting chronological | data as to the time of appearance of the different phe- nomena. The time is in each case taken from the mo- ment of artificial fecundation. After a lapse of five minutes, the spermatozoid has forced an entrance into the ovule.* At the expiration of ten minutes (that is, five minutes after entrance), it has reached the centre of the ovule. At twelve minutes, the female nucleus - has put itself in motion to meet the spermatic nucle- *M. Balbiani, Cours sur la fécondation, passim. Y¥ournal de Micrographie Vol. III. 1879. OF MICRO-ORGANISMS. 83 us. Finally, at the twentieth minute, the two nuclei have united. In the psychical history of animal fecundation as just given, there are many gaps: the history of vege- table fecundation will fill several of these. The simplest forms of sexual reproduction in veg- etables are those where the male and female cellules are quite the same and advance to meet each other equally; thus possessing not only the same form, but also the same properties. In a small Alga bearing the name of Vlothrix serrata, the interior of certain cellules divides into two parts, which separate, then come to- gether again and mingle anew into a minute mass which, when set at liberty, reproduces the plant entire. In other species the inside divides into small naked cellules, which are first set at lhberty and for some time move briskly about in the water by means of cilia with which they are provided, before fusing into one another. These cellules are called zodspores. The _differentiation is further marked in certain species, the zoospores of which have neither the same farm nor the same properties. Some leave their positions to go to meet the others: these are the male cellules, the an- therozoids; others make no movement at all and limit their ~dé/e to that of waiting: these are the zodspores. Similarly, in an Alga bearing the name of Spheroplea annulina, there are found two kinds of filaments, brown and green. In the green filaments the proto- plasm of certain cellules breaks up into a definite num- ber of ovoid bodies which remain immobile; in the in- terim, the cellules of the brown filaments liberate mo- bile spores provided with two flagella: these spores, veritable male cellules, ply briskly about in the water and then proceed to fix themselves to the green fila- 84 THE PSV CHLOALIFLE ments, the cellules of which are pierced by pores; through these orifices they penetrate into the cellules and fuse with the immobile ovoid bodies, which are nothing else than zodspores. ; The psychical phenomena attending this mode of conjugation may be still more complicated, as shown by the observation that Berthold has made upon the conjugation of the zodéspores of the Lctocarpus silicu- losus. The Ectocarpus belongs toa group of algz char- acterized by the presence of mobile spores which re- produce the plant. These zodspores are little pear- shaped cellules, of which the tapering end 1s colorless, and the rounded end shows a brownish-green colora- tion, which is due to the presence of an extensive chromatophore; at the edge of the chromatophore a deep depression is sharply marked, which appears to be aneye. Every zoéspore is equipped, in addition, with two flagella, which rise from the same point of the lateral skirt of the anterior extremity of the body; one of these flagella points forwards and the other backwards. When the zodspores are set at liberty and begin to swim about unnoticed. The female cellule does not draw about her the male cellules, from which, moreover, it differs by no Fig. 9. —Sexual ree morphological mark. But at a given production of the £cfo- carpus siliculosus. Dif- moment the female zodspore becomes ferent stages of the fe- male zodspore while distinguished from the male cellules entering the state of rest (after Berthold). by passing into astate of rest; where- to, the base of the anterior flagellum, which is laterally , in the water, they pass each other by é inserted, proceeds to blend with the anterior part of — the body with the effect that the flagellum appears to rise from the extremity; during the same time, it OF MICRO-ORGANISMS. 85 contracts, and presents at its free end a slight pro- tuberance, which allows the zoéspore to fix itself upon an immobile point; as to the rear flagellum, it slips back upon the posterior part of the body which it encompasses, and finally disappears.—When the fe- male zodspore has become motionless, the male zo6- spores, hitherto indifferent, are seen to make towards it and to surround it ina half-circle; the number of zoospores that thus meet, is quite considerable; it frequently exceeds a hundred (fig. 10). They let their second flagellum float loosely behind them, while they all direct their anterior filament towards the fe- male cellule; this filament they draw back and forth over the Fig. ro. —Sexual reproduc. body of the female cellule; they ee reg Cr ee perform upon it real acts of feel- rounded by male zobspores. ing the object of which is evi- dently to provoke in the female zodspore a genital ex- citation, as what follows will prove. It happens at times that several of the male zodspores quit the ranks and make off; they are immediately replaced by others who employ their filaments in a —m Ukemanner,tostroke 6:9) the female. Finally, upon the expiration of a certain time, Fig, rr. — Sexual reproduction of the Zcto- ONC of the zoospores carpus stliculosus. Successive stages of the 1 h half-ci copulation of a female zoéspore with one of the 1€AVES the hali-cir- ] 6 ; “a aight cle and approaches the female. The two zodspores unite; after having presented the series of changes marked in the figure,— 86 HE IPSUCH LEC Leis when the fusion is complete,—the female cellule loses its fixatory filament and the little zygote, the result of the fusion, is set free. When the male zoéspore is obliged to go a long distance to reach the female zodspore, it has been thought that the latter secretes a substance which acts upon the male cellule as a chemical excitant and which marks out for him the direction to follow. The supposition is quite probable; it was suggested by Strasburger, who had shown that the spermatozoids of the Marchantia polymorpha are attracted by the substance that issues from the archegonium. It will only be necessary to assist at an experiment of artifi- cial fecundation with fish-spawn, in order to come to the same opinion. The sperm introduced into the liquid preparation does not spread about homogene- ously in all directions; the spermatozoids are observed -to whirl about the ovules in great masses; it must be supposed, further, that there is some excitation of an unknown nature which attracts the spermatozoid to- wards the micropyle, for this minute opening, of which the diameter is scarcely that of the head of a sperma- tozoid, is the only orifice through which the male ele- ment can enter into the ovule to fecundate it. These ingenious opinions have been latterly con- firmed by the very interesting experiments of M. Pfeffer, professor at the University of Tiibingen, upon 3 the movements of spermatozoids.* His investigations had to do principally with the spermatozoids of cryp- tograms. M. Pfeffer discovered that certain chemical substances have the property of attracting these sper- matozoids. * Pfeffer, Untersuchungen aus dent botanischen Institut zu Tibingen, Vol. I. Leipzig, 1884, p. 363. OF MICRO-ORGANISMS. 87 The manner of conducting the experiment is as follows. A solution of the substance to be experi- mented upon is placed in small capillary tubes with a light-aperture of from five to seven hundredths of a millimeter wide. These capillary tubes dip into a watch-crystal covered with a liquid, wherein quantities of spermatozoids have been placed. Under these cir- cumstances currents of diffusion are soon set up be- tween the tube and the liquid in the watch-crystal, and when the substance experimented upon is’ the proper one, the spermatozoids are seen to follow the currents of diffusion and to penetrate into the tube. The substance exerting such attraction varies with the plants. The author began by experimenting upon the spermatozoids of certain ferns (Adiantum cuneatum). After a great many fruitless trials, one substance, and one only, proved to be effective: namely, a solution of malic acid or malate. It is to be presumed, then, that, in the organic kingdom, malic acid must be the substance acting as a chemical ex- citation upon the spermatozoids of ferns and guiding them towards the female cellule. According to the hypothesis of Pfeffer, the actual process takes place in the following manner. The spore of a fern, falling upon humid ground, germinates and gives birth to a green cordate slip, the prothat- lium, upon which are developed the male organs or anthertdia, and the female organs or archegonia. At — a certain moment, elongate cellules, spirally twisted and extremely mobile, issue from the antheridium: these are the spermatozoids. They are equipped with vibratile cilia, by the help of which they are able to start in search of the female cellule. At the same in- stant, the female organ, the archegonium, opens and 88 THE? PSYCHIC TILL emits a mucilaginous substance, which must contain malic acid or a malate, for these compounds are the particular excitatory substance of the fern-spermato- zoids. Thanks to a drop of dew that falls upon the prothallium, the spermatozoids swim around and ap- proach the female ovule, which attracts them by acting upon them with the malic acid. A confirmation of this hypothesis is primarily the fact, that all substances tested, with the exception of malic acid and malates, remained completely inactive; another proof is, that malic acid is found in prothal- lium-decoctions of the Preris serrudata and of the Ad- zantum capillus veneris; another proof still, is the cir- cumstance that malic acid is largely diffused through- out the vegetable kingdom. The author has made, in this connection, a series of very curious experiments upon the degree of con- centration necessary to attract the spermatozoids. The lower limit at which attraction begins, is found in a solution containing malic acid in the proportion of one to 1000 parts. This the author has designated by a favorite word of the Germans: ezz-Schwelle, or, in other words, the threshold of excitation. When the solution in the watch-crystal contains one part malic acid to every thousand parts, in order to make the spermatozoids pass from the watch-crystal into the tube, the solution held in the tube must be thirty times as strong, or 30 x I-1000 = 3-100. Ifthe liquid in the watch-crystal contains one part malic acid to every hundred parts, similarly the solution of the tube must be thirty times as strong, that is to say three tenths. : The author justly compares the result of these ex- periments with the law laid down by Weber, which M. Of MICRO-ORGANISMS. 89 Delbceuf has happily formulated as follows: “The slightest difference capable of being felt between two excitations of the same sort is due to an actual differ- ence that increases proportionally with the excitations themselves.” Thus, in order to tell that one weight is heavier than another, it must be heavier than the other by a fractional difference which varies from one third to one fifth according to the individual, be the original weight what it may. For example, to a weight of three grammes, in order that a difference may be made perceptible, we must add one third of three grammes orone gramme. To four grammes we must add one third of four grammes, or one and one third grammes, etc.* _ According to Pfeffer, the application of Weber’s law to his experiments is so exact that, when the solution of the tube is only twenty times stronger than that of the watch-crystal, the spermatozoids remain unaf- fected. Furthermore, the application of the law is not disturbed by changes of temperature varying within certain limits. Thus, down to a temperature of + 5° (41° Fahr.) the spermatozoids remain sensible to a concentration of liquid thirty times as strong as that in which they are. Basing his calculations upon these experiments, the author has succeeded in determining the probable quantity of malic acid that must be contained in the archegonium. This quantity is probably in the pro- portion of three tenths. The spermatozoids of the Se/aginella are likewise wise attracted by malic acid and the malates. As re- gards the Marciliacee, the specific substance has not been discovered. The same failure, also, in the case * Consult Ribot, Psychologie allemande, p. 161. ca go + EL OPS V CPL ee barre | ; of the Hepatice. The author concludes from this, that the substance operating in these two cases can be little diffused throughout the vegetable kingdom. For the spermatozoids of the /unarita hygrometrica (Conferve), the operative substance 1s cane-sugar. No other attracts them. The spermatozoids remain unaffected even by substances bearing the closest anal- ogies with cane-sugar. We will cite, by way of ex- ample, fruit-sugar or levulose, grape-sugar or glucose, glycogen, manna, milk-sugar, etc.; these substances exert no attraction upon the movements of the sper- matozoids, whereas cane-sugar exercises an attraction so powerful that the capillary tube becomes at once crammed with them. The excitation first induces in the spermatozoid a movement of direction: the body is brought into a position enabling it to reach the tube by movement in a straight line. The same phenome- non has been observed by Strasburger in the case of Algze zodspores; when these minute beings are at- tracted by a chemical or luminous excitation, the first thing that happens is the directing of the body towards the attracting source. A solution of one in one thousand parts is suffi- | ciently concentrated to draw the spermatozoids of Mosses into the capillary tubes.. The “threshold of excitation”? for them, accordingly, is» the same as for the spermatozoids of ferns. Furthermore, Weber’s law is in this instance again verified; only, in order to have the chemical excitation produce a different at- traction, it must be stronger than the first in the pro- portion of 50 to 100. In the experiments upon the spermatozoids of ferns the ratio is a little smaller; be- ing only 30 to 100. The question presented itself to the author as to OF MICRO-ORGANISMS. gi whether, by increasing the degree of concentration, a point would not be reached where attraction would change to repulsion; he has not made the experiment, but he has noticed that great numbers of spermato- zoids still penetrate into the tube when contain- ing a solution in the proportion of 15 to 100, not- withstanding the fact that they there meet a speedy death. The general conclusion to be derived from these numerous experiments is, first, that the spermatozoids are sensible to certain chemical excitations, and conse- quently, that in every group of plants there exists a special substance acting the part of a specific excitant towards the spermatozoids. The author does not hes- itate to regard the spermatozoids as a physiological re-agent of such substances, allowing feeble traces of the same to be detected in a liquid solution. He thus comes to form a sfermatozotd test, which is not with- out analogy with the Bacteria test, invented by En- gelmann. An application of the test is the following: a decoction of herbs having presented the property of attracting the spermatozoids of Mosses, the author concluded that the decoction must contain cane- sugar. Vill. THE PHYSIOLOGICAL FUNCTION OF THE NUCLEUS. It would be of the highest importance to know what is the seat of the phenomena of the life of re- lation in the bodies of Micro-organisms. We have seen that Micro-organisms are the equivalent of a simple cellule, composed, according to the classic plan, of a protoplasm, of a cellular nucleus, and of an enveloping membrane. 92 LAE PSVCHLOC LATE Each of these elements plays a part of special im- portance in the vital phenomena of these beings. Long since, scientists have attributed movement, sensibility, and the prehension of foods, to the proto- plasm. This was the result of direct observation. While observing an Amceba, for example, the protoplasm is seen to undergo modifications of form and to throw out pseudopods, either for the purpose of effecting a change of position, or to seize alimentary substances. The protoplasm, accordingly, seems to be the sole agent of all these phenomena. Likewise, the vibratile cilia of the Ciliates, which are at once organs of mo- tion, prehension, and touch; the suckers of the Acin- etinide, which are special organs of prehension, are nothing else than outward expansions of the proto- plasm proper. As regards the enveloping membrane, the same cannot discharge any psychical function: firstly, be- cause it is a product of protoplasmic secretion; and, secondly, because it is wanting in many Protozoans and even in many animalcula quite high in point of organization that, despite their nudity, exhibit marks of psychic life just as complex as those observed in Infusoria having a cuticle. The part acted by the nu- cleus does not so clearly manifest itself to direct ob- servation; it executes no movements in the ordinary conditions of life; it remains motionless in the centre of the animal’s body, surrounded on all sides by the protoplasm; unlike the latter, it is not in direct con- tact with the outside world. The first phenomena that have enabled us to con- jecture as to the significance of the nucleus, have to do with the division of cellules; when a cellule divides, the nucleus comes into action, it exhibits certain OF MICRO-ORGANISMS. 93 movements, and passes through complicated stages which have been given the name of caryokinesis.* But these complex phenomena simply show the function of the nucleus as an histological element; they do not afford any disclosures as to the physiolog- ical vd/e of the nucleus in the cellule. Other observations have enabled naturalists to sur- mise what phenomena are subject to the action of the nucleus. In 1881, Balbiani called attention to indi- viduals, belonging to the species Paramecium aurelia, that were destitute of a nucleus and which neverthe- less possessed the power of locomotion the same as ordinary individuals; whence, he concluded that the nuclei exerted no influence upon the phenomena of individual life. Shortly afterwards, Gruber observed small specimens of the Actznophrys sol which absorbed nutriment, changed their position in the liquid, and even fused with each other (zygosis), but which were nevertheless destitute of a nucleus.} The idea then occurred to Gruber, and to Nuss- baum likewise, to divide the Micro-organisms by ar- tificial means into several fragments, of which some would contain a nucleus and others not, and then to watch what would come of it. Gruber, to whose ex- periments the most importance attaches, chose as his subject of trial the Stentor cwruleus, a ciliated Infu- sory of great size, which exhibits a nucleus resembling a chaplet of beads (moniliform). He afterwards con- tinued his experiments upon other species, and his conclusion was, that the power to regenerate lost parts belonged to all Protozoans, but that this phenomenon only took place when the isolated fragment contained * kdpvov, the nut, and Kivyoic, motion, disturbance. + Contributions to the Bzologisches Centralblatt, 1885. p. 73. 94 THE PSYCHLICALLFE some portion of the nucleus; in which case the animal reproduces all the organs it has lost in consequence of its dissection. Furthermore, the process of the for- mation is exactly the same as in the spontaneous di- vision of these same Infusoria. The excitation caused by their removal is accordingly of the same character as the unknown excitation that provokes the natural division of the body. From these experiments, the part acted by the nu- cleus is indicated by complete evidence. Gruber shows that in a single instance only can a fragment without a nucleus form itself anew; and that is, when the frag- ment contains an organ in course of formation, as hap- pens, for example, during the spontaneous division of the animal. This amounts to saying, that the presence of a nucleus is necessary to give the impulse to the formation of the organ, but that it is not necessary to the completion of the organ when the impulse has ~once been given. Lastly, if the fragment is totally destitute of a nu- cleus, it does not re-form itself so as to constitute a complete animal again; if the fragment possesses nel- ther mouth nor peristome, it does not reproduce a new mouth and a new peristome;.yet the fragments continue to live and to move. The absence of a nu- cleus does not suspend the functions of motion, sensi- bility, nutrition, or growth. This conclusion is, in our estimation, too sweeping, as.we shall see fur-— ther on.* M. Balbiani has recently repeated these experi- ments of artificial division, and, while confirming in * We have taken as our guide, with the permission of M. Balbiani, the lec- tures delivered by that eminent authority at the Collége de France, in May, 1887. a ake OF MICRO-ORGANISMS. 95 general the results of Gruber as to the function of the nucleus in the vital phenomena of ciliated Infusoria, he has endeavored to fix with more exactness a cer- tain number of important points. His first experi- ments, like those of Gruber, were conducted upon the Stentor ceruleus, a species of which the size renders it better adapted to this sort of experimenting. In an observation which we shall take as a type, and which is represented by the figure sent to us by M. Balbiani, the body of the Stentor is cut by two transverse sec- tions; three divisions are obtained, each of which con- tains a fragment of the nucleus. We will remember that the nucleus of the Stentor is like a long string of beads; it is not at all rare to see a fragment of a Sten- tor contain one or more beads. eo Fig, 72.—Artificial division of the Stextor ceruleus. (After Balbiani.) Let us follow the phenomena presented in the middle segment. This segment contains only a single grain of the nuclear chaplet; directly after severance, it assumed a globular shape; the day following, it had lengthened, had grown a tail at the posterior extrem- ity, and upon the anterior part there had appeared, distinctly outlined, a crown of cilia longer than those upon the body; in other words, a peristome had —_ gO. - THE OPSVCHIC (LIE formed; the day after, the fragment had increased considerably in bulk, and in two days more the ani- mal had formed a mouth. During this time, the nuclear grain had multiphed: five, in fact, were counted. The animal had the normal form; its size, however, was a little smaller than that of the ordinary Stentors. Thus, through the action of a small quantity of nu- clear substance, the fragment has been completely re- constructed. It frequently happens that the artificial severing of the animal causes various deformations in the frag- ments. The deformation disappears with the greatest rapidity in fragments containing nuclear substance. The wound heals instantly; directly after severance, the two edges of the wound are seen to adjust them- | selves to each other. In all these particulars, the experiments confirm the results obtained by Gruber. M. Balbiani desired to ascertain what would hap- pen if the division were made during the state of con- jugation. Conjugation, as we know, aims at replacing an old, spent element, that has lost its physiological proper- ties, by an element of new formation proceeding from an attendant nucleus (nucleolus) exchanged between the individuals in conjugation. The point in question was to ascertain whether the nucleus that was be- ginning to disappear, had lost its regenerative power. In the Stentors, during conjugation, this old nucleus breaks, and its nuclear globules are scattered to all parts of the protoplasm. When at this stage, the body of one of the Stentors is divided in such a manner that the fragment contains some of the scattered globules that came from the old nucleus. It is quite evident OF MICRO-ORGANISMS. 97 that such a fragment is obtainable only by mere acci- dent. In an experiment which we again cite as a type of many others, the fragment containing the elements of the old nucleus tends to reconstruct itself; this frag- ment, which represented the posterior part of the animal, presented, the day following, a rudimentary peristome; the reconstruction did not go beyond this point: it was left incomplete. Accordingly, the old nu- cleus loses its power of regeneration. As to the phenomena presented in fragments con- taining no nuclear substance, M. Balbiani has made decided advances in the question; he hascompleted the experiments of Gruber, he has also corrected them, and he has reached conclusions essentially different. In order to understand more thoroughly the phe- nomena connected with the absence of nuclear sub- stance, the author has directed his attention to an- other species, the Cyrtostomum leucas, which has the advantage that it can be kept longer alive than the Stentor can, on a glass slide holding a drop of water. The Cyrtostomum is a large ciliated Infusory of more than four-tenths of a millimeter in length. Its proto- plasm is differentiated into two layers, one of which, the cortical, encloses very heavy trichocysts; the other, the endoplasm, holds alimentary substances. The an- imal exhibits upon one of its faces a mouth, shaped like a long narrow buttonhole, and upon the other face acontractile vesicle, from which crooked and an- astomosed passages radiate. It is easy, by making a transversal division, to obtain fragments without nu- clear matter; the nucleus of the Cyrtostomum being formed of a single, round mass. But it is not easy, on the other hand, to obtain fragments likely to live, 98 THE PSYCHIC LIFE since this animalcule has a dense ectoplasm, and, when severed, this layer, which is not very retractile, does not grow together again and close the wound; the sides remain separated, the water comes in con- tact with the endoplasm, which swells, bulges out, and runs from the wound; the animal may thus void itself completely, dying of diffluence. It occasionally hap- pens that the animal voids itself only in part, and that the nucleus escapes with a small piece of the proto- plasm. Then, if the wound draws together, we get a fragment that has thrown out the nucleus by its own action. ~ We shall not speak of the actions of the fragment containing nuclear substance; they are the same as observed in the case of Stentors: the fragment rapidly reconstructs itself and re-forms a complete animal. Let us mark more closely the fragment without nu- cleus. Such fragments continue to live for some time; they have been keptalive as long as eight days; but they do not reconstruct themselves; they do not even assume a regular form; the part of the body fac- ing the section retains its obliquity of truncation. At the start, for the first few days, the movements con- tinue; a curious circumstance connected therewith is, that the fragments continue to move in the direction in which they would have moved if they were placed together to form a complete individual.. The vibratile cilia are in no wise altered; they shake with the same animation as before. Only the movements of the an- imal are a trifle irregular; but they exhibit the same marks of volition as seen in normal individuals. The vesicle continues to contract. The power to seize food is also retained when the OF MICRO-ORGANISMS. 99 fragment without nucleus contains the mouth; the mouth ingests alimentary substances. If the Cyrtosto- mum be given grains of potato fecula, which it is very partial to, the fragment without nucleus, but with a mouth, swallows these grains and fills itself with them. It is not known whether it digests them. This much was observed in the first stages, and Gruber was wrong in stopping at this point. At the expiration of a certain time, varying be- tween the third and fourth day, alterations of structure are noticed in the fragment that are probably traceable to the absence of the nucleus. One of the first to take place is the disappearance of the marks of ditferentia- tion which we have observed to distinguish the endo- plasm from the ectoplasm. The dark granules that fill the interior of the body congregate in the centre by abandoning the peripheral part; then these granules scatter and come toa position just beneath the cuticle, which denotes a deliquescence of the plasma. The layer of trichocysts undergoes changes and disap- pears. All these alterations result from an actual dis- organization of the plasma. The contractile vesicle shrinks, its pulsations decrease, the radiating passages disappear. The body of the animal, which in its nor- mal condition is elongate, becomes rounded; its move- ments flag and consist of nothing but a rotation of the body about its own axis; at last the animal be- comes motionless and dies of diffluence. These changes are not due to lack of sustenance, as one might suppose; for fragments that have a mouth and swallow food, pass through the same alter- ations as those that have no mouth.* * M. Balbiani has informed us, upon request, that the fragments of Cyr- tostomum furnished with nucleus can be kept alive for a much longer time 100 THE. PSYCHIC LIFE: It is superfluous to insist upon the importance of these results, obtained by a method that might be called experimental physiology applied to unicellular organisms. Although the experiments have been made solely with ciliated Infusoria, the results of the same may be extended to all cellules, for the Infusoria are nothing more than autonomous cellules living an independent life. The conclusion from the above researches of M. Balbiani, which, as we have seen, go far beyond those of Gruber, is, that the nucleus is not necessary merely to the regeneration of the parts, as the German pro- fessor believed. The error made by Gruber arose from the fact that he did not follow the career of the fragments deprived of a nucleus long enough; if he had continued his observations, he would have seen that the fragment becomes gradually disorganized. The nucleus, according!y, has not merely a formative power; it does not merely regulate alimentation, re- — adjustment of form, and the healing of wounds; it has not merely a regenerative power, enabling the plasma to reconstruct complete the organs lost by artificial severance. The nucleus is, besides all this, an essen- tial factor of the plasm’s vitality. If a fragment of protoplasm be deprived of its nucleus, the fragment remains alive for some time, but afterwards under- goes disorganization. Such are the facts, extremely complex, and conse- quently difficult to summarize by a formulated state- ment. under the same conditions (that is, in a dropof water on a glass slide kept in the moist chamber of Malassez): in this way it is possible to keep them alive for the space of a month, by introducing into the liquid a few Infusoria to serve them as food. On the other hand, the fragments deprived of nucleus by sec- tion live for only eight days at the most. OF MICRO-ORGANISMS. IOI We certainly cannot regard the protoplasm as in- ert matter; but what appears. probable is, that the pro- toplasm receives from the nucleus the communication, - the delegation of physiological powers. The nucleus is in a certain sense the focal seat of life in all its forms. If we get rid of the nucleus by artificial section, the fragment of enucleated protoplasm continues to live for some time, having received from the nucleus an impulsion that has not yet been exhausted; but af- ter a certain length of time, the impulsion given by the nucleus not being renewed, the protoplasm runs its course and dies. From the psychical point of view, which more par- ticularly occupies our attention here, how are the re- sults of these experiments in cellular vivisection to be explained? When a fragment of an organism, deprived of nuclear substance, is seen to move about freely and with the same activity as if it still possessed its nu- cleus, we are constrained to admit that the phenom- ena of the life of relation, or movement and sen- sibility, have their seat in the protoplasm. But it is probable that such physiological capacities as the powers of nutritfon, are not inherent in protoplasm; they depend immediately upon the presence of the nucleus, for they disappear little by little and finally vanish a few days after the removal of the nucleus.* It may be mentioned in passing, that there are cer- tain psychical properties which the nucleus apparently does not transmit to the protoplasm, but which it re- tains for itself; this is the case with the instinct of gen- * The difficult question here, is to ascertain whether the psychical proper- ties of the protoplasm are destroyed through the direct effect of the disorgan- ization of the plasma, or whether they disappear a short time before the process of disorganization and in consequence of the absence of nuclear sub- stance. 102 LLL ik SVGCHLG. Loy Lees eration. We have already seen that, during the epi- demic periods of conjugation, the Paramecia which have their nuclei overrun with parasites cease to con- jugate with animals of the same species. The destruc- tion of their nucleus by the Bacteria produces in the Paramecia the effect of actual castration. The removal of the nucleus, accordingly, causes the interruption of the following functions and in the following order as to time: 1. The regenerative and reproductive property of the plasma; 2. The vitality of the plasma, and the psychical functions. The psychologist will notice with interest that the psychical function of the protoplasm outlives the re- generative function for an appreciable length of time; a fragment of a cellule which, having been mutilated by the act of severance, is unable to correct its out- ward form, or to secrete a fresh cuticle, or to recon- struct its lost organs, is nevertheless still capable of perceiving sensations and of responding thereto by movements. Psychical life is consequently a prop- erty of living matter which appears to be less complex than the regenerative property, inasmuch as it ceases later. | To summarize, the nucleus plays the primordial vole in the cellule; if, to use an old comparison of Ar- istotle’s, we compare the protoplasm to the clay, we must compare the nucleus to the potter that fashions it. The nucleus comprehends all the physiological properties, the totality of which goes to constitute life. It is interesting to note what perfect accord pre- vails between these recently discovered facts and the OF MICRO-ORGANISMS. 103 phenomena relative to fecundation. Fecundation con- sists in the fusion of two nuclei, of which one proceeds from the male, and one from the female. Thus, it is through the intermediary office of the nucleus that all the faculties, all the properties possessed by the par- ents,—the form of their bodies as well as their psychi- cal faculties,—are transmitted to the embryo; as we have just remarked, therefore, all these properties must be comprehended in the nucleus, in order to pass into the embryo. We must note further, that the embryo takes from the mother something besides the nucleus. While itis connected with the father through the head of the spermatozoid, which has the morphological value of a nucleus, it receives from the mother not only the fe- male nucleus but also the vitelline plasma of the ovule; now, as the embryo does not exhibit a greater morphological likeness to the mother than to the fa- ther, we may thence infer that the vitelline protoplasm inherited from the mother exerts no formative influ- ence upon the development of its body. These are not the only facts the connection of which we desire to show with the results of experi- ments upon the function of the nucleus. It will be well to point out here, how reproduction is effected among organisms which, besides their nucleus, possess other differentiated organs. The best known and perhaps the most general mode of reproduction 1s fissiparity, which consists in a division of the entire body into two equal parts. If we closely follow the course of this phenomenon in any organism whatever, we shall find that the division begins by a multiplication of the principal organs of the body. The nucleus begins by lengthening out and assuming a position perpendicu- ~ 104 THE PSYCHIC LIFE lar to the plane of division. The first organ that mul- tiplies is the flagellum; it does not split into two parts, as several English authors have supposed; according to the observations of Biitschli and of Klebs, a second flagellum is formed complete. The pigmentary spot also does not divide into two parts; the old eye re- mains by a sort of preference with one of the parts, while the other part acquires a new eye, formed com- - plete; this is likewise the case with the mouth and the cesophagus. There are only two elements that multi- ply by division: the chromatophores and the nucleus. Now, when we note that the chromatophores contain a body, the pyrenoid, which exhibits the closest analogy of chemical composition with the nucleus, we may properly say that the nuclear elements of the cellule are the only ones that do not reproduce by neoforma- tion at the expense of the protoplasm, as is the case with the cilia and the flagella. The reason for this mode of multiplication by nu- clear elements will be comprehended, if we consider the matter in the light of experiments made upon the formative properties of the nucleus. We have seen, in fact, that the nucleus can regenerate the protoplasm, but that the protoplasm cannot regenerate the nucleus. We now see that the regeneration of organs lost in consequence of the.spontaneous division of cellules, is subjected to the same law as the regeneration follow- ing upon artificial division; the protoplasm cannot re- generate a nuclear element any more in the one case than in the other; in order to effect reproduction, therefore, this element must divide. OF MICRO-ORGANISMS. 105 IX. CONCLUSION. THE conclusions relative to psychological phenom- ena arrived at in the foregoing treatise, are in contra- diction with the opinions generally received upon the psychology of the cell. Scientists have held, that cell- ular psychology is represented wholly and solely by the laws of irritability. In his Zssaz de Psychologie Générale, a work in so many respects remarkable, M. Richet has assumed the advocacy of this view; the correctness of which we have no hesitation in disput- ing. In the work just mentioned, the distinguished professor has written the following: “There exist simple beings which appear to be nothing more than a homogeneous assemblage of irri- table cellules. Motory reaction, consequent upon irritation’ from without, constitutes their life of rela- tion. Irritability is their life complete, but this, in effect, is psychic life; so that cellular irritability can be considered the same as elementary psychic life.” From an attentive perusal of this passage it will be seen that M. Richet brings within the category of irritability, not only unicellular organisms, but also pluricellular organisms formed by the union of homo- geneous cellules. M. Romanes, in his work upon Mental Evolution, without coming to a conclusion so definite as M. Richet, seems to us to have reduced the psychic ac- tivity of proto-organisms to within very narrow limits. We are impressed with the fact upon glancing over . his Diagram of Mental Evolution: he recognizes nothing but excitability, for example, in the ovule and spermatozoid of man. This is manifestly erroneous. 106 THE PSY CHICRELLE The sexual elements, and especially the spermatozoid, of all unicellular organisms are certainly the ones which show the most highly developed psychical functions: the act of seeking and approaching the ovule, which is frequently situated at quite some distance from where the male element is deposited; the length of road to:be traveled; the obstacles to be overcome; all point to faculties in the spermatozoid that are not explainable by simple irritability. : Hitherto, apparently, writers who have essayed to present the psychology of micro-organisms, have con- tented themselves with schematic notions instead of basing their theories upon the direct observation of these interesting creatures. By the aid of exact data, we have shown that in both vegetable and animal micro-organisms phenomena are encountered which pertain to a highly complex psychology, and which appear quite out of proportion to the minute mass that serves them as a substratum. We shall first of all advert to the term irritability, — which, though long in use, has not in our opinion been happily chosen; since it is in the highest degree ambig- uous, and not suggestive of an exact signification. — We might call to mind in this connection, the reflec- tion made by Kant upon obscure properties, which he compares to easy-chairs upon which the mind unbends itself and rests. In place of discussing words, let us endeavor to discuss facts. What are we to understand by irritability? We may give the expression a very broad or a very re- stricted meaning. We may makeit express the prop- erty which every organism possesses, of reacting upon excitation. In this general sense we may say that irritability includes within itself all of psychology, OF MICRO-ORGANISMS. 107 the most highly developed, as well as the most ele- mentary; for upon ultimate analysis every psychical manifestation consists in a response to an excitation. Evidently, it is not in this: general and somewhat common sense that M. Richet has intended to employ the word. For a more exact definition, let us consult his work, of which, a whole chapter, the first, is de- voted to this subject; the author enumerates and de- velops at length the laws of irritability: ' 1. Every action that modifies the actual condition of a cell is an irritant of that cell. . 2. Every external force, provided it has a certain intensity, is capable of inducing cellular irritability. 3. The movement in response to irritation is pro- ’ portional to the excitation. 4. The movement in response to irritation is, for equal irritations, stronger in proportion as the equilib- rium of the cell is less stable; in other words, stronger in proportion as the cell is more excitable. 5. The response to the irritation, is a movement in the form of a wave, which has a very short latent pe- riod, a period of ascent, correspondingly brief, and a very long period of descent. 6. The movement of the cell upon irritation is, for equal irritations, stronger in proportion as the irrita- tion has been more sudden. 7. The movement in response to a brief irritation lasts much longer than the irritation has lasted. 8. Forces which, alone, appear impotent, become effective when repeated; for they have, in spite of their apparent inefficacy, increased the excitability of the organism. The statement of these various laws, gives the term irritability a precision which it lacked. M. Richet had 108 LE PSYCHIC LILLE in view particularly the muscular fibres, and the laws of irritability are only supposed to cover a series of physiological experiments made upon the reaction of a striated muscle. They are not, then, hypothetical laws, but are much rather particular experiments gen- eralized and extended to undifferentiated protoplasm. It is proper to remark here, that we have not as yet — been able, by means of direct experiments, to ascer- tain from life the laws of irritability in undifferentiated protoplasm. The experiments made upon this point,— for instance, the experiment causing the protoplasm of a detached cell to contract by means of an electric current,—have not yet been brought toa precise result; for the structure of protoplasm is so delicate and so complex, that even the slightest excitation suffices to produce an alteration, and since it is difficult to distin- guish the contraction of the protoplasm from its coag- ulation. But we shall pass by this subordinate ques- tion. The question now remains, whether the compli- cated experiments made in muscular physiology, which M. Richet generalizes and extends to the physiology of all cellules, include and comprehend the whole psy- chology of an independent organism, and whether we may say with M. Richet, that irritability (thus under- stood) represents all of cellular psychology. Plainly not. The numerous facts which we have cited in the foregoing essay, transcend the too narrow limits within which it has been attempted to confine the psychology of the cell. We shall restrict our- selves to the mention of one of these phenomena, to show the complexity of the psychic life of micro-organ- isms: it is the existence of a power of selection, exer- cised either in the search for food, or in the manceu- OF MICRO-ORGANISMS 10g vres attending conjugation. This act of selection is a capital phenomenon; we may take it as the character- istic feature of functions pertaining to the nervous system. As Romanes has indeed observed, the power of choice may be regarded as the criterion of psy- chical faculties. Going farther, we might be able to say that selection comprehends the properties of the nervous cellule, as irritability comprehends the prop- erties of the muscular cellule. Scientists have endeavored to explain the mechan- ism of this choice. They have pretended to solve it by saying that it was dependent upon the relation be- _ tween the chemical composition of the cellule making the choice and the chemical composition of the body : selected. ; Such explanations are purely verbal. Undoubt- edly, the faculty of selection, of which protoplasm seems to be possessed, is founded in the character of its chemical composition. Chemistry lies at the basis of physiology, but chemistry does not explain physiology, and it is quite evident that that property . which protoplasm possesses of making a choice be- tween several excitations, is a physiological property. However that may be, we may resume all the fore- going into the statement that every micro-organism has a psychic life, the complexity of which transcends the limits of cellular irritability, from the fact that every micro-organism possesses a faculty of selection; it chooses its food, as it likewise chooses the animal with which it copulates. M. Richet has defended his opinion in opposition to the one I have pronounded, in a note published in the Revue Philosophique for Febuary 1888, wherein he speaks as follows: IIO THE PSYCHIC TARE At the beginning of his essay upon the Psychic Life of Micro- Organisms (Revue Philosophique), M. Binet expresses himself as follows: ‘‘In the lower beings that represent the simplest forms of life, we find manifestations of an intelligence which greatly trans- cends the phenomena of cellular irritability. Thus even on the very lowest rounds of the ladder of life, psychic manifestations are very much more complex than is usually believed, and the concep- tion of cellular psychology which some very recent authors have formed, seems to me a very crude analysis of the most delicate of phenomena.” AsI have upheldin my Zssaz de Psychologie Généra/e,and in some measure—however little—developed this admitedly old idea, that cellular irritability is the beginning of psychical activity, I request the permission to speak in defence of an opinion so roughly han- dled by M. Binet. Now, it appears to me that M. Binet has allowed himself to become involved in illusion respecting the word cellule. A cell, in the eyes of the embryologist and the morphologist, has a well-de- fined meaning. But M. Binet does not seem to have comprehended the fact, that for the physiologist and the psychologist, the essen- tial condition of cellular unity is homogeneity. It is possible that the infusoria, the strange story of whose life M. Binet relates to us, are single-celled organisms. I am in no wise qualified to decide as to this; but whether a single cell, or a group of cells, it matters little, in my opinion, provided the single cell is differentiated to the same degree that it would be if composed of several cells not homogeneous. I appeal to M. Binet himself and to the cuts of his essay. When he shows us an “zug/lena with eyes, esophagus, mouth, contractile vesicle, contractile reservoir (fig. 6); when he carefully describes the shape of the flagellum, the nettle-like tentacles, the tongue- shaped organs, the ocular spots, the trichocysts, and the peristome; when he assumes special vervous centres endowed with various at- tributes (p. 22): he cannot induce us to admit that the psychology of these complicated organisms is the same as the psychology of the simple cell. I repeat, it is quite immaterial to me that people affirm by the authority of embryology that this or that is a single cell. If that cellule have ocular organs, a nervous system, a mouth, an esophagus, and a heart, I shall, despite any and every hypoth- esis of the embryologists, refuse to regard it as being physiologi- cally a homogeneous cell, as is, for example, a muscular fibre. OF MICRO-ORGANISMS. TBI The size will not affect the matter at all. The same desires, says Montaigne, stir mite and elephant alike. The psychic life of the bee is as complex as that of the whale, and if a microscopic in- fusory possess eyes, mouth, prickles, and heart, it evidently pos- sesses them in order that itmay make useof them, and accordingly I shall treat it as a complex organism upon the same ground that I do a snail or a grasshopper. Embryology will not force me to the extremity of regarding such a creature as a simple organism be- cause it is derived from a single cell. In my opinion, therefore, it is that unfortunate word ztce//u- far, that has made M. Binet believe that, Infusoria being unicel- lular organisms, the elementary psychology of the cellule applied to them. M. Binet has allowed himself to be deceived by a word— a thing that often happens in matters of science. For my own part, in order to avoid any confusion, I would like to say that the elementary psychology of the cellule ought not by rights to be ap- plied to anything except to homogeneous cellules; for the psychol- ogy that has to do with complex cells—real organisms with organs and apparatus of their own—must certainly be as complex as the psychology of animals wholly differentiated. The laws of irritability act in all their simplicity and rigor among simple beings. In fact, in every instance of investigation into the nature of simple organisms, or such as appear simple by the optical instruments at our disposal (a fact that does not always Tigorously prove their simplicity), as bacteria, for example,—we find that chemical irritability is the apparently sole law of move- ment. What else, indeed, are the movements of those bacteria so thoroughly studied by M. Engelmann, if not an affinity for oxygen, in other words the simplest and most universal chemical phenom- enon in all nature? And so the critigue of M. Binet will not stand. On the con- trary, it seems to be well established that complex organisms, whether single-celled or many-celled, have a psychology corre- sponding in complexity to the degree of differentiation their organs have attained, while simple beings—and they are simple only if homogeneous—have a simple psychology which is probably con- tained in the laws of Irritability only. Cu. RICHET. My reply to the letter of M. Richet, published in the same number of the Revue Philosophigue, may be offered as a general conclusion to my work. With the BIg LHE PSYCHIC LIRT omission of all polemical features, it is in substance as follows: In giving the psychology of these microscopic creatures the name of cellular psychology, I have not invented a new term, nor given a new sense to an old one. Quite some time before me, M. Heckel had made a study of cellular psychology and his investiga- tions, like my own, were based entirely upon the observation of animal and vegetable micro-organisms. Furthermore, micro-or- ganisms being represented by a single cellule (and this doctrine is now universally accepted), the study of their psychical manifesta- tions can, in my opinion, with perfect propriety be styled cellular psychology. M. Richet takes exception to the use of the latter expression; but he does so while substituting for the old definition of the word . cell, one quite his own. To him, a micro-organism like the Eu- glena, which has an eye, a mouth, an esophagus, and a contractile vesicle, would not beacellule. To admit the latter view, means, in his own words, to become involved in illusion respecting the word cellule. In our judgment, the question here is by no means one of optical illusion, but one of verbal definition. What, ac- cordingly, is a cellule? ‘‘ For the physiologist and psychologist,” says M. Richet, ‘‘ the cellule has not a distinct entity, or, at least, that entity, that unity, lacks an essential condition, namely, homo- geneity.” To M. Richet, the cellule is a homogeneous body; a body that comprises differentiated parts is not a cellule. ~ It is unnecessary to remark upon how far the latter concep- tion of a cellule diverges from the usual and commonly accepted | definition of the word. Hitherto, scientists have understood by the term cellule, a body made up of the union of two essential parts, a quantity of protoplasm and a nucleus. The scientific world argues as to whether elementary forms exist which do not contain a nucleusand which should be termed cyfodes, as proposed by M. Heckel. The careful observation of micro-organisms by means of perfected technical processes has enabled us to discover hundreds. of nuclei in the very cellules which M. Haeckel classed among the cytodes. Such is notably the case with many algz and lower-class fungi. The Moners—a group of micro-organisms believed to have no nucleus—grow numerically less and less, in proportion as they are more carefully studied. It is true, we are now no more able OF MICRO-ORGANISMS. — 113 than formerly, to show the presence of a nucleus in bacteria; but that does not prove that the bacteria have none. Our knowledge of the morphology of microscopic organisms is wholly relative, and depends upon the degree of perfection attained by technical science. _When we bear in mind that the presence of a nucleus re- mained for a long time unobserved in organisms several hundred times larger than the bacteria, we ought not to besurprised at hav- ing been unable to discover one in these smaller creatures. We may even go further, and question the material existence of a body formed solely of protoplasm, basing our opinion upon the ex- _ periments of Gruber, Nussbaum, and Balbiani, as reported in my article, and upon the more recent observations of Klebs which are in perfect agreement with the results of the investigators just cited. All have shown that the nucleus is an element essential to the life of the cellule, and that, when a fragment of a cellular body strip- ped of a nucleus is procured by artificial section, this fragment does not reproduce the organs it lost by being severed; it does not heal its wound, it does not refashion its form, and, what is more, at the end of a certain time its protoplasm, being withdrawn from the in- fluence of the nucleus, suffers complete disorganization. These experiments were made not only upon animal micro-organisms, but upon vegetable cells also. They prove the primordial importance of the nucleus in the cellule and thereby render doubtful the exis- tence of cellules deprived of a nucleus. Since every cellule contains, in all likelihood, two distinct dif- ferentiated elements, the protoplasm and the nucleus, which have neither the same physical structure, nor the same chemical nature, nor the same physiological functions, we may understand that it would be exceedingly difficult to name a single instance of a simple homogeneous cellule. It is the proper place to add that neither protoplasm nor nucleus, each regarded by itself, are homo- geneous substances. . It is unnecessary to enumerate all the investi- gations that have been made upon this point. Let us call to mind merely the fact that from the morphological point of view proto- plasm appears to be composed of two substances, a homogeneous semi-liquid substance and a firmer substance exhibiting, as auth- orities upon the subject say, sometimes the form of detached fila- ments and at others a structure of a reticulate character. At the present day, accordingly, it is impossible to allow that homogeneous cellules exist, without falling back to Dujardin’s 114 THE PSYCHIC LIFE theory of the sarcode. There are really no simple organisms, and such as appear so are merely imperfectly known. However, it will not do perhaps to take literally the terms em- ployed by M. Richet. When he speaks of homogeneous cellules it is possible that he wishes to speak merely of cellules in which, aside from the nucleus, no other differentiated organ is to be found. Now, it is quite important to note that, even of organisms made up simply of protoplasm and nucleus, the psychology is ex- tremely complicated, and is not contained exclusively in the laws of irritability. The Vampyrella Spirogyre, classed by Zopf among the animal- fungi, and the place of which is still so little known, is a being the body of which is composed of protoplasm and nucleus simply. So far no other differentiated organ has been found in thiscreature, except from one to four contractile vesicles. Employing the ter- minology of M. Richet, perhaps we ought to call this being a sim- ple cellule; yet this simple cellule has quite a complicated psy- chology: it exercises choice in the selection of its food, attacking Spirogyra only. : The same is the case with the M/onas amyli, which, having neither eye nor mouth, represents to M. Richet a simple cellule; still, the J/onas amyli exercises choice in selecting its food, as it feeds exclusively on grains of starch. The structural elements of the tissues do not differ from the micro-organisms whose psychological history I have endeavored to unfold, so much as might be imagined: they show the same powers of selection, and on this point I shall only instance the epithelial cel- , lules of the intestines or the phagocyte cellules, the attributes of which I have described in my essay, and which are able to dis- criminate, for instance, between bits of fat and particles of coal, absorbing the former and leaving the latter. I repeat it, therefore, no living cellule, strictly so defined, is a simple cellule, and Ido not think that M. Richet has advanced a fit- ting illustration in mentioning the muscular cell, for the latter is one of the most highly differentiated that there are. I cannot imagine, accordingly, to what elements, to what be- ings clearly defined, we could apply the simple-cellular psychology reduced to mere irritability, that M. Richet asks me to distinguish from the complex-cellular psychology, which would be exclusively reserved for the animal and vegetable micro-organisms that I have described. OF MICRO-ORGANISMS. PUL It appears to me that this simple-cellular psychology lacks a foundation; it is a conception of the mind, rather than a study based upon observed facts. In M. Richet’s book I find no indication as to what sort of be- ings he means to distinguish thereby. He contents himself (pp. 20 and 27) with speaking of simple beings without otherwise defining them. ‘Towards the close of his remarks upon my work, M. Richet cites an instance of simple beings, viz., the bacteria; in his judg- ment, chemical irritability appears to be the sole law conditioning their movements. What are the movements of the bacteria, he asks, if not an affinity for oxygen; in other words, the simplest and most universal chemical phenomenon that exists in all nature? In our judgment the latter phrase is to be taken metaphorically. We believe that as yet no one has demonstrated that the move- ments of a living being, in moving towards a distant object, how- ever simple they may be, can be explained merely by a chemical affinity acting between that being and that object. It is certainly not chemical affinity that is acting, but much rather a physiological need. Psychic life, like its substratum, living matter, is, when closely studied, an exceedingly complex subject. This fact is, with me, a profound conviction; it rests, not upon abstract ideas and methods, but upon the observations that I have given, observa- tions that are not founded upon my own personal authority alone, but which are drawn from the highest authorities, and most of which I have been able to verify with my own eyes. ALFRED BINET. a THE PSYCHIC LIFE. APPENDIX. ell The subjoined cuts, explanatory of the conjugation of Micro-organisms, refer respectively to the descrip- tions on pages 67, 67 and 68, 68, 69 and 70, 71 and 72. Fig. 7 2.—Positions preliminary to conjugation among the faramectum aurelza, (Balbiani.) Fig. 7 4.—Several pairs of Stentor Fig. 7¢. Position preliminary to ceruleus fixed upon a conferva fila- the copulation of the Stylonychia ment, enlarged fifteen diameters mytilus, The two animals are super- (after Balbiani). imposed upon each other by their ventral faces (Balbiani), OF MICRO-ORGANISMS. 117 Fig. 7 d2.—Gemmiform conjugation of the Vorticellinze (Carchestun poly- pinum). ai Mae Ht vs rae i Pix | at Ms Uy, jah LX i rf er e. Bae ft: ee % “ od iy } ual 2 Be — ns: ss din ig x 5 Ay x tie ; LF erp neon enh a ol nae * of a6@ vedette- Od ARS oh ae SO yshogen ged ahaha) mtyat pet be,» Oh Gen etien ‘ SU. pe tolepes , "ne 4 ; A edaeuaa - . 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