THE PSYCHIC LIFE OF MICRO-ORGANISMS BY ALFRED BINET. , . - ' • , ''.-•"••' '•'•: •-•'";•-•• ': :_: ; -.. . i... •• '•'.''•' ' • • ': . - •'•'• : - " . ' • - THE PSYCHIC LIFE OF MICRO-ORGANISMS A STUDY IN EXPERIMENTAL PSYCHOLOGY BY ALFRED BINET SECOND REPRINT EDITION CHICAGO THE OPEN COURT PUBLISHING COMPANY LONDON AGENTS KEGAN PAUL. TRENCH. TRUBNER & Co., LTD. 1910 TRANSLATION SANCTIONED BY THE AUTHOR COPYRIGHT BY THE OPEN COURT PUBLISHING Co, 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 existence 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, Vitalismus und Meehaitisinus, Bin Vortrag, 1886. iv PREFA CE. 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 in 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. v 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 zoological 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 larva? 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 chat 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 Moebius, 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 zoology 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 zoological 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 zoological scale, assigns the first manifes- tations of surprise and fear to the larvae of insects and to the An- vi PREFA CE. 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, Mosbius, 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 larvae of insects and with Annelids. We give, in con- tradiction of this statement, the recent observations of Verworn, f which reveal the existence of curious instincts among the Rhizopods. The Difflugia 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 Difflugia 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, Zeitschriftfiir U'issenschaftliche Zoologie, Bd. 46. H. 4. 1888. PREFACE. vn 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 Difflugia collects the materials for providing the young individual with a case, 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 Difflugia exhibits great pre- cision; for the Difflugia 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 larvae 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 more than a 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. Pages 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- table cellule 1-4 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 Bittschli upon the flagellum of the Glenodinium cinctum. — Metabolic infusoria. — The granulous bands and bright filaments. — The contractile vesicle. — The move- ments of Bacteria and Gregarinae 4-20 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. 20-22 THE ORGANS OF SENSE. Organs of touch. — Organs of sight. — Ocular spot in Flag- ellates.— Ocular spot of vegetable zoospores. — Experi- ments of Klebs upon the structure of these spots. — The 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. Kunstler upon the eye of Phacus. — Observation of Claparede and Lach- mann. — Observation of Lieberkiihn. — Sensitiveness of the Euglena to light. — Experiments of Engelmann. — The vesi- cles of Muller in the Loxodes rostrum 22-31 II. NUTRITION. Psychical phenomena connected with respiration. — Search for oxygen by the bacteria of putrefied matter. — Observa- tion of Engelmann 3J~34 in. 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 Euglena and the Peranema. — Nutrition by endosmosis, or saprophytic. — Animal nutrition, choice of nutriment. — Prehension of foods by the Amoeba, the Actin- ophrys, the Monas, the Acineta. — Opinion of M. Mau- pas upon choice by preference. — Capture of food. — The vof ticel Ciliates. --The Hunter Ciliates. — The Amphileptus. — The Didinium nasutum. — Movements of defense and flight 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 CONTENTS. Pages Volvox. — Difference between a pluricellular organism and a colony of unicellular organisms. — Voluntary combina- tions.— The Bodo caudatus 55~6i v. 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 61-65 VI. FECUNDATION. Fecundation among Infusoria. — Historical. — Psychological preliminaries of fecundation — Observations of M. Bal- biani upon the Paramaecia, the Spirostomes, and the Sten- tors. — Copulation. — Fecundation among the Vorticels. — Observation of Engelmann. — Material phenomena in fec- undation.— The role of the nucleus, and the role of the nucleolus. — Description of the phenomena as seen in the Chilodon cucullulus (see appendix), the Paramcecium bursa- ria and in the Param&dum aurelia. — Observation of M. Balbiani upon Paramaecia, of which the nucleus is overrun with parasites 65-75 VII. 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. — Observation of Fol upon the fecundation of the star-fish. — The cone of attraction. — CONTENTS. xi Pages 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 Ectocarpus sili- 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- tion of Weber's law 75~9i VIII. 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 Stentor cceruleus. — 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 Micro-organisms 92-105 IX. CONCLUSION. Statement of M. Richet's position respecting cellular psy- chology 105 xii CONTENTS. Pages Romanes's conception of the psychic activity of Proto- organisms , . . , 105 Irritability and cellular psychology 107-110 Correspondence between Ch. Richet and Alfred Binet, ap- pearing in the Revue Philosopkique of February, 1888, re- printed from THE OPEN COURT of December 27, 1888.110-115 APPENDIX. Additional cuts illustrative of : The Conjugation of the Param&cium awelia 116 The Conjugation of the Stentor c&ruleus 116 The Copulation of the Stylonichia mytilus 116 The Conjugation of the Carcheshtrn polypinum 117 The Conjugation of the Chilodon cuciilluhts (with explana- tions) 1 18 Addenda. Notes and References omitted in the text. 121 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 2 THE PSYCHIC LIFE stands to reason. If a 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 incertcz sedis, which bota- nists usually place in the vegetable kingdom, but which zoologists 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. Dinoflagellates. Radiolarians. Sarcosporidia. Cystoflagellates Myxosporidia. Microsporidia. We propose, now, to study the psychic life of these lower organisms, or, to speak in more general terms, their life of relation. It is 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 in a 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, 4 THE PSYCHIC LIFE 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 organ 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. I. 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, comprises 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 Amoeba 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 amoeba 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 amosba 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 THE PSYCHIC LIFE 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 (4- 45° to 4- 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 (Carchesium) 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, their elongation, cannot in any case be considered as a direct act of the contractility of the protoplasm. "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 amoeba, consist of two parts, an enveloping membrane or ectosarc, 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, Amoeba terri- cola, it has seemed to me that the most external mem- brane of the ectosarc showed striae of a granular ap- pearance which may be identical with the striae or 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 by a 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 Petalobus of Lachmann, initial traces of differentiation of the pseudopodia have been observed; they always form at the same 8 THE PSYCHIC LIFE 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 Vibratile 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 larvae 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 Hcterotricha, they also cover the whole surface of the body, but they are unequal in length. To this group belong the Stentors which have long cilia in- serted around a circular surface, extending almost to the mouth. This surface is a rotatory organ, analo- OF MICR O-ORGA NfSMS. 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 Hypotricha 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 to the 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; it is 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 THE PSYCHIC LIFE other observers, there exist also in vibratile cellules filiform striae 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 amoeboid 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 like that of the amoeba, we observe the slender and filamentous 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 nasutum (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 by a rapid rota- tory movement of 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. i. — Didinium na- sutiim (Balbiani) Fig- ure representing move- ment forward. The cilia are all turned" towards the front part of the body. Fig. 2. — Didinium na- sutum (Balbiani). Out- line of movement back- wards. The cilia are all turned towards the back part of the body. Fig. 3. — Didinium na- sutum (Balbiani). A sketch of rotatory movement in one spot. 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. i); 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 THE PSYCHIC LIFE 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- 4) or of the rising of the temperature (from + 35 to -h 40) or under the influence of various chemical substances, the large cilia, the organs of voluntary movement, are OF MICR O-ORGA NISMS. 1 3 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. 7 he 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 Euglenadeses 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 THE PSYCHIC LIFE 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 Trichomonas; 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 -D the zoospores 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- able and rigid, while the free end alone executes movements destined to drive r. c. = contractile re- servoir; o. = eye; /. food to the mouth, which is generally = disk of the para- ° myione; ch. = chro- situated at the base of the flagellum. matophores; «. =nu- cieus. Ehrenberg gives to the flagellum the name proboscis; its peculiar mobility renders it worthy of this name. The flagellum, like the vibratile cilium, is an expansion of the protoplasm through the envel- oping membrane. M. Certes has observed a Proto- Fig. 4. Euglenadeses. OF MICR O- OR G AN I SMS. 1 5 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. Biitschli has recently made a very interesting ob- servation 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- ium 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 Biitschli gives us a curious example of the phe- nomena of autotomy, which have recently been studied by Fredericq. 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 Vorticellae are supported by contractile 1 6 THE PSYCHIC LIFE 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 Lieberkiihn, 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, Kolliker, 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 sar- cous elements of Bowman. Lieberkiihn, 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 striae are in intimate connection with the basilar extremity of the vibratile cilia. In the Vorticellae 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 by no means agree as to its ex- act function; Biitschli and Stein consider it to be a 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 Vorticellae, every eight seconds; in the Euplotes, every twenty-eight seconds; in the Acineria incurvata, 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 i8 THE PSYCHIC LIFE 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 Vorticellae are mounted, contracts. Still more obscure is the oscillatory movement of the Bacteria. These small beings are very mobile when OF MICR O-ORGA NISMS. 1 9 they find themselves in a 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 THE PSYCHIC LIFE plain the phenomena of motility among certain Pro- tozoa and Protophytes. Nervous System. Hitherto 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- tiplies 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 F*s- J- stemor in pro- bridge of protoplasm exhibit perfect cess of division' 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 THE PSYCHIC LIFE 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 two 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 of certain 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 spinal cord, and lastly the medulla, which is the ultimum moriens. 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. 23 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 Euglenae), 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 THE PSYCHIC LIFE 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 Euglena 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 zoospores exhibit at the anterior, and Fig. ^.-Anterior extremity of usually colorless, extremity of their bodies, a small red point which seems to have exactly the tractile reservoir' same structure as the red spot of the Euglenae. 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 priori 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 Euglenae 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 drops 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 a state of rest; the stagnant spores of the algae also assume a red 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 Euglena (word for word, pretty eye), which he had given to a species of Flagellates provided with ocular spots. This interpretation had been questioned 26 THE PSYCHIC LIFE by all the authors of his time, especially by 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 is 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 MICR O- OR GANISMS. 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 from 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 Diatomaceae and Desmidiaceae. It is ad- mitted to-day that certain Peridinia possess an eye, an organ which has hitherto been 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- dition an 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. Kimstler (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 THE PSYCHIC LIFE globule, acting as a crystalline 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 Freia 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 those phenom- ena which M. Ehrenberg, in the Ophryoglenae, 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 Ophryoglenae, and some- times there was discovered behind it a very trans- parent corpuscle, which involuntarily gave rise in the mind to the idea of a crystalline 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 of a 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 crystalline humor. OF MICR O-ORGA NISMS. 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 it is 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. A second 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-actions 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 theflagellum, 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 Euglenae always congregate in the band F to G of the spectrum. So far as the vegetable Micro-organisms are con- 30 THE PSYCHIC LIFE cerned, we have already mentioned that a large num- ber of the algae zoospores 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 Euglena?. 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 a cap 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 Volvocinae which modern botanists place among the algae. (We are 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 MICR O-ORGA NISMS. 3 1 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 Ccelenterata are apparently composed of a vesiculiform capsule enclosing a solid concretion, called otolith. Thus it is possible that the vesicles of Miiller may be auditory vesicles. Up to the present time this organ has not been met with in any other species of Protozoa. ii. 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 THE PSYCHIC LIFE 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 chlorophyl algae, or green Euglenae, 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 aerobious 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 chlorophyl grains, which, hid from the light, cease to disengage oxygen. The clustering begins anew, if a ray of sunlight is again let touch the chlorophyl. OF MICR O- OR GANISMS. 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 algae, 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 yel- 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 light. 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. in. 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. i. Vegetable nutrition, or according to Biitschli's expression, holophytic. This is the method of nutri- tion among animal or vegetable cellules that contain 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 exclusively 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 PSYCHIC LIFE These little bodies, which in the vegetables are called leucites, 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 diato- min. The latter coloring substance can be absorbed by alcohol. The Euglenoididae, the Chlamydomonadidae, and the Volvocinae exhibit enormous chromatophores. In the case of the Euglenae, 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- monadidae and the Volvocinae 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, it is 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 Trypjyp, 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 Kiinstler, 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 order 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 THE PSYCHIC LIFE Euglenae 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 no function? It is the presence of chromatophores that prevents certain Flagellates from feeding like animals; so much so in fact, that the digestive apparatus performs its functions in Flagellates which have no chromato- phores and are not provided with chlorophyl 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 sapropkytic. 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 PSYCHIC LIFE memory and volition. We shall group our remarks under the two following heads: a. The choice of food; and b. 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 Algae, Diatomaceae, 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 MICR O- OR GANISMS. 4 1 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, for example, 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 Amoeba, 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 amoeba 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 Amoeba 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 Amoeba 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 THE PSYCHIC LIFE 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 Amoeba 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 Amoeba. 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 Amoeba. 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 MICR O- OR GA NISMS. 43 other species of higher organization, this mode of ali- mentation is rendered impossible by the cutitcle which encompasses the body; the 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 im- 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 lip. 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 Monas, 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, for the protuberance which lies 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. Butschli has made an analo- gous observation with the Oikomonas termo. The prehension of food comprehends, here, three phases, in two of which the organism manifests psychical activity : first, attraction of food by means 44 THE PSYCHIC LIFE of the flagellum ; second, formation of the vesicle which extends towards and envelops the food, when the latter has come near; third, absorption of the food. The Acinetae 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 a vacuum. 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 Acinetae, 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 Acinetidse 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 Acinetidae 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 Cole ps hirtus can throw itself upon the terrible suckers of the Podophrys fixa. The stout shell with which this little Infusory is enveloped, serves it as a shield and guards it from the deadly grasp of the Acine- tidae. The Acinetidae 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 htstrio, like all other Stylonichiae, has a very soft tegumentary envelope. They are accordingly seized and devoured by the Acinetidae without difficult}'. 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 Acinetidas. 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 zig- 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 salt an s 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 light- ning and disappears from the field of vision. For a 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 debris, in the midst of which, bending and twisting, it slips about with wonderful nimbleness. The Lagynus crassicolis, on the other hand, moves along at a pace quite constant and uniform, neither slow nor rapid. It searches about among algae and fragmentary parti- cles. The Peritromus Emmce moves slowly. It runs lazily over the Algae, where it seeks its nutriment, and does not stray from them to venture into the open water. OF MICR O-ORGA NT SMS. 4) 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: First, 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. "In the first group the mouth is always held wide open, and along with the nutritive particles which the current of the vortex 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 THE PSYCHIC LIFE 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 (vid. 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 manoeu- 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 rinding 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 MICR O-ORGA NISMS. 49 P 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 Lagynus 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. With a tem- 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 5o THE PSYCHIC LIFE 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 Epistylis plicatilis. The Epis- tylis are colonizing vorticels of which certain individ- ual members attain a size of not less than 0-21 mm. The Epistylis 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 Claparede, "in the hope of seeing what would come of the manoeuvre, an Amphileptus, which was slowly creeping upon a colony of Epistylis. The way in which it approached the Vorticels, feeling them, so to OF MICR O- OR GANISMS. 5 1 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 Epistylis like the finger of a glove being drawn upon a ringer 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 ^ /;///«'/ , » c .— /-. >-, .S > 5,0 e fa """ o tn O « D— ' 2' O i"5 S u -a u i- o 0) C OF MICRO- ORGANISMS. 1 19 other one of the capsules produced by the division of the nucleolus, so that when we come to the phase of the process represented in figure C, we find an animal which contains, besides its nucleus, two nucleolar segments in immediate proximity (nit' nit'); it was the same in figure B; each animal already possessed two nucleolar seg- ments, but these segments were obtained from the division of the nucleolus properly belonging to the animal itself, while in figure C, in consequence of an exchange effected, one of the nucleolar seg- ments belongs originally to each animal and the other comes from its mate. M. Balbiani, who made the first observations upon these phe- nomena of a nature so delicate and complex, originally supposed that the two adjacent nucleolar segments, which have been rep- resented in the figure C, were produced by the longitudinal di- vision of the nucleolus exchanged between the two animals in con- jugation. M. Maupas has recently proposed a different explanation, which seems to be further corroborated by the very figure given twenty years previously by M. Balbiani. According to M. Maupas the segment exchanged proceeds to fuse with the segment not exchanged, in order to form a compound segment; the two con- tiguous segments, seen in figure C, would not, therefore, be the re- sult of the division of one segment solely, but the first stage of the conjugation of two elements having different origins. A fact which apparently argues in favor of this opinion, is the aspect presented by the two segments; if they proceed from a division, we would find there certain phenomena of caryokinesis, which were further- more completely unknown at the time when M. Balbiani made his first observations. However this may be, it is seen by figure C that the regression of the old nucleus («) is sharply marked. In the figure D, the two nucleolar segments have fused to- gether and have formed a compound segment, which segmentates in its own turn; the two new products of that segmentation grow to unequal sizes; the largest capsule attains a size of forty thou- sandths of a mm. ; it is this that forms the new nucleus of the Chilodon. The second capsule shrinks and becomes compressed, it takes its place beside the first one and becomes the new nucleolus. The figure E represents the last stage of the phenomenon; the animal is in possession of its new nucleus and its new nucleolus; 120 THE PSYCHIC LIFE the old nucleus is reduced to a small pale and rumpled mass and will shortly disappear. To recapitulate, then, if the opinion of M. Maupas (who did not study this species, but like ones) be accepted, the nucleolus di- vides into two capsules: the one, playing the part of a male ele- ment, is exchanged between the two animals in conjugation, and proceeds to fuse with one of the capsules derived from the division of the nucleolus of the other animal; the other capsule, which acts the part of a female element fuses in the same way with the male element coming from the other animal. The result of that fusion is a compound capsule which, undergoing a process of division, pro- duces the new nucleus and the new nucleolus of the animal fecun- dated. ADDENDA. NOTES, References, Authorities, etc., omitted in the text: Page i, line 16. The doctrine of unicellularity in regard to the Infusoria has been upheld by Sibold and Kolliker; the ma- jority of naturalists have conceded it. Page 9. line 21, et seq., vide Pfliiger's Arch., Vol. XXIII, 1880. Page 10, line 4, vide Rouget, Revue Scientifique. March 15, 1884. Page 10, line 13, vide Annales des Sciences Naturelles, 1835, Vol. IV, pp. 348 and *6i. Page 12, line 29, et seq., vide Arbeiten aus dem zoolog. Institut in Wiirzburg, herausgegeben von Prof. C. Semper, Vol. I. p. 9, 1872. Page 15, lines 12 and 13, vide Morphologisches Jahrbuch, Vol. X. 1885, p. 534. Page 16, line 25, vide Pfliiger's Arch., 1876. Page 19, line 28, vide Balbiani, Lecons stir les Sporozoaires. Page, 20, line 6. By protoplasm in this connection is understood the entire cellular body; the distinction of function between the protoplasm properly so called, and the nucleus, is estab- lished later on in the essay. Page 26, lines 9 and 10, vide Comptes rendus de r Acad. des Sciences, Nov. 2, 1886, No. 18. Page 29, line 26, vide Bot. Zeitung, 1881, 1883, 1884, 1886. Page 46, last line, vide E. Maupas, Etude des Infusoires cities, Arch, de zobl. exper., 1883, No. 4. Page 58, lines 30 and 31, vide Henneguy, Sitr la reproduction du Volvox dioique. Acad. des Sciences, July 24, 1876. • •' . .-.. - . ....':. . __,Y .. . .- ' • •'•; I ,. ... .,.,., - ' : I •'„: ; - • - ;':'•' . -v •• • • •< I •• ';-:;,... .• •• : - ,. ... :. •• ••;•..,.-• '-•: .• • . •: