THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA PRESENTED BY PROF. CHARLES A. KOFOID AND MRS. PRUDENCE W. KOFOID PROTOPLASM ; OR, Life, Matter, and Mind. ARISTOPH. Aves, 686. PROTOPLASM ; OR, LIFE, MATTER, AND MIND. BY LIONEL S. BEALE, M.B., F.R.S, Fellow of the Royal College of Phyfidans ; Phyfician to King's College Hofpltal. NUMEROUS COLOURED DRAWINGS, EXECUTED ON WOOD, AND COPIED FROM THE OBJECTS THEMSELVES. SECOND EDITION, REVISED AND MUCH ENLARGED. LONDON: J. CHURCHILL & SONS, NEW BURLINGTON STREET. 1870. [All Rights reserved.} B3 1 TO THE READER. THE nature of the changes which occur in matter that is alive has always excited great interest ; it is a question which arrests the attention of all educated persons, as well as of those who make the pursuit and advancement of natural science their life work. The enquiry is necessarily brought under the attention of every student of medicine, and it is natural that physicians who have time and oppor- tunity, should be led to investigate deeply some of its ramifications. The minute structure and action of the tissues and organs of living beings, in health and disease, early attracted my notice. It is a study which has had a rare charm for me from boyhood, and for upwards of twenty years I have been dili- gently engaged in original research as well as in public teaching in this particular department of science. Some of the observations I have made are recorded in this work. I have avoided the use of technical terms, and have tried to say what I have to say in the simplest manner. To save lengthy descrip- tions a few drawings of some of the specimens upon vi TO THE READER, which my observations were made have been added with explanations of the points which these are in- tended to illustrate. My views upon the nature of vital actions are at variance with the doctrines now generally entertained and taught. I am therefore very desirous that those interested in the subject should have in small com- pass the general statement of the facts as they appear to me. It is to be regretted that upon the most elementary propositions connected with this enquiry opinions are sadly conflicting, and many of the facts and statements upon which they are based and which are urged in their behalf are quite irrecon- cileable with one another. It is therefore very dim- cult for readers to form an impartial judgment. But I trust it is not too much to ask that the observations which have led me to the views I entertain, should be brought under the notice of those who have not yet subscribed to the doctrine that living things are mere machines built up by physical forces only, and made to act by force alone. Intense energy and activity are displayed by certain members of the new school in giving publicity to their views ; they press them in many different forms, and endeavour to enforce the acceptance of the physical doctrine of life, and much besides which it is supposed to include, with all the proverbial ardour and authority of prophets. All this renders it very desirable that every one who is engaged in actually investigating a matter of such deep general interest, TO THE READER. vii should do his utmost to make the conclusions at which he arrives intelligible, without affectation of learning, without mystery, and without in any way exaggerating the importance of what he may have to communicate. For the public may reasonably desire some calm statement of proved facts in a matter of such importance. It should be the writer's en- deavour to tell his story simply, so that those who wish may learn, and to take pains to make the facts as clear to other minds as they appear to his own, without trying to amaze by calling in the aid of startling similes and striking illustrations which but too often divert the attention from the real matter under consideration, and are calculated to distract the mind and prejudice the judgment. In this edition I have introduced a new section on the Mind. The views now published in a connected form for the first time, were put forth in my lectures delivered by direction of the .Radcliffe Trustees, at Oxford during the Michaelmas term of last year, reported in the " Medical Times " and " Gazette," and less systematically in my physiological lectures de- livered at King's College, London, during the winter sessions 1863 to 1869. 6 1 , Grosvenor Street ; Christmas, 1869. * # * The degree of amplifying power used is stated at the foot of each figure in diameters, or linear measure. x 500, means that the representation is 500 times longer or wider, measured in one direction only, than the object itself. If the object was i inch in length, the drawing would extend over 500 inches, or would be 41 feet 8 inches long. The diameter of any object can be ascertained by com- parison with the scales at the foot of each plate. TABLE OF CONTENTS. I. PHYSICAL LIFE AND ITS BASIS. PAGE Introduction ... ... .., ... ... ... ... ... I Professor Owen's New Views ... ... ... ... ... ... 5 Note on Ciliary Action ... ... ... ... ... ... 7 Mr. Grove on Experimental Organism ... ... ... ... 9 The term "Protoplasm" II Huxley's " Endoplast" and "Periplastic Substance" 13 Protoplasm the Physical Basis of Life ... ... ... ... 16 Bathybius of Huxley ... 22 Dr. Wallich's Observations ... ... ... ... ... ... 24 Chemistry of Protoplasm ... ... ... ... ... ... 25 Properties of Matter ... ... ... ... .. ... ... 27 A quosity and Vitality ... ... ... ... ... ... ... 28 Summary of the Things included under " Protoplasm" ... ... 29 II. GERMINAL, OR LIVING MATTER, AND FORMED MATTER. Nothing that Lives is Alive in every Part ... .. ... ... 33 Germinal Matter and Formed Material ... ... ... ... 35 The Terms Living and Formed Matter and Pabulum ... ... 37 General Characters of Germinal Matter ... ... ... ... 38 Amoeba... ... ... ... ... ... ... ... ... 39 On Vital Movements 40 Mucus Corpuscle ... . 42 Of New Centres Nuclei and Nucleoli 45 TABLE OF CONTENTS. PAGE Of the Production of formed Material ... ... ... ... 49 Of the So-called Intercellular Substance ... ... 52 Of the Formation of the Contractile Tissue of Muscle ... ... 54 The Formation of Nerve Fibres ... ,.. ... 55 What is Essential to the Cell 55 Cells are not like Bricks in a Wall ... ... ... ... ... 56 On the Nutrition of a Living Cell .. ... ... ... ... 57 Of the Increase of Cells ... 58 Of the Changes of the Cell in Disease ... ... ... ... 59 Effects of Treatment ... ... ... ... ... ... ... 64 III. OF LIFE. What is to be understood by the term ? ... ... ... ... 61 Non-living Particles of Matter contrasted with Living Particles ... 69 Spontaneous Generation ... ... ... ... ... ... 73 Structure of a Spore of Mildew ... ... ... ... ... 75 Is a Tissue " Living" because attached to a Living Organism ... 79 Chemical and Mechanical Changes in Living Beings ... ... 79 Actions in Living Beings ... ... ... ... ... ... 82 Force guided by Matter ... ... ... ... ... ... 83 Actions which characterize every kind of Living Matter, but which never occur in any Form of Non-living Matter. New Views concerning the Vital Processes of Growth and Nu- trition ... ... ... ... ... ... ... ... 87 Germinal Matter and Formed Material of the Blood ... ... 96 Nature of the Material which Nourishes the Tissues ... ... 98 Peculiarity of the Nutritive Process... 101 Of Vitality. Vitality not a Property of Matter ... ... ... ... ... 103 Point at which the Physical School tries to stop further Enquiry ... 107 Of a Living Spherule ... ... ... ... ... ... ... 109 Centrifugal Movement of Living Particles ... ... ... ...in TABLE OF CONTENTS. xi PAGE New Centres not formed by aggregation ... ... ... ...112 Alteration in Vital Power ... ... ... ... ... ... 113 Increased Action ... ... ... ... ... ... ... 114 Hypothesis of Vital Force ... ... ... ... ... ... 116 General Survey of the Phenomena of Living Beings ... ... 118 IV. OF MIND. Of Nerve Action in general ... ... ... ... ... ... 123 Of the Nerve Current 126 Different kinds of Nerve Force ... ... ... ... ... 127 Of the Structure of Nerve Apparatus ... ... ... ... 129 Of Mental Ntrvoiis Action. Of the Mechanism and its Formation ... ... ... ... 130 Are Mental Nervous Actions of the Nature of Reflex Actions ? ... 133 The Brain is not a Gland ... ... ... ... ... ... 136 Of Mind as a Function of the Brain ... ... ... ... ... 136 Of Mental as compared with Mechanical Action ... ... ... 140. Of Thought as a Result of Chemical Action... ... ... ... 142 Is the Brain to be looked upon as a Voltaic Battery ? ... ... 143 On Expressing Thoughts ... ... ... ... ... ... 145 Of the Living Matter concerned in Mental Action. Of the Germinal Matter taking part in Mental Operations ... ... 149 Difference between this and other kinds of Germinal Matter ... 150 Of the Order in which different kinds of Germinal Matter are affected in Disease... ... ... ... ... ... ... 151 Origin of Germinal Matter ... ... ... ... ... ... 153 New Powers acquired in Development ... ... ... ... 154 Effects of Exercise ... ... ... ... ... 155 Of the Nature of Will, and of the Life of Germinal Matter taking part in Mental Operations ... ... ... ... ... 156 GERMINAL OH LIVING MATTER AND FORMED MATERIAL OF COMMON MILDEW. In this drawing the germinal or living matter of mildew duiing growth is represented. The figures have been copied from specimens well stained by immersion in carmine fluid, a, spores protected by a thick layer of formed material. 6, smallest particles of germinal or living matter within ; any one of these minute particles might grow, c, a spore bursting ; germinal matter escaping, d, a spore enlarged by growth, e, a spore sprouting. /, an old spore, the formed material of which has b<-en much thickened by the formation of new layers within. The remaining figures show the growth of the long filaments (mycelium) and the fructification of the fungus. It will be noticed that in all these changes the germinal matter only takes part. The formed material is perfectly passive, and does not GROW. Magnified 17CO diameters. lOOCth of an inch PHYSICAL LIFE AND ITS BASIS. [HE opinion that life is a form or mode of energy or motion has for many years past been gaining an increased number of advocates, and now ap- pears to be very generally entertained and taught by scientific men. The idea that life is a power, force, or property of a special and peculiar kind, temporarily influ- encing matter and its ordinary forces, but entirely different from, and in no way correlated with any of these, has been ridiculed, and is often spoken of as if it were too absurd to require refutation. And yet it is doubtful if any one who has carefully studied the matter is fully satisfied as to the accuracy of the facts, and the cogency of the arguments advanced in favour of the physical doctrine of life. The very positive affirmations made by some authorities, un- supported as they are by well-demonstrated facts, almost suggest to the reader a suspicion whether after all, the writer himself believes the doctrine to which he has com- mitted himself, and which he has determined to advocate with all the force of his authority, and to the very utmost of his power, to be really true. It may be that facts recently discovered strongly support PROTOPLASM. this now popular notion : it may be that the tendency of modern research is, as has been said, indubitably and strongly in this direction, but some of us cannot feel satis- fied that this is really so. Surely it is not too much to ask that the exact way should be pointed out in which new facts afford support to the doctrine, and that we should be furnished with something more definite to guide our reason than what is called the " tendency" of investigation, of thought, or opinion; for this " tendency," when carefully analyzed, will sometimes be found to amount only to this, that certain influential persons have determined that a par- ticular opinion shall be widely taught, or a particular theory agreed upon shall be expounded and diffused as widely and as quickly as possible. Disclaiming authority of every kind, the adherents of the new school of opinion profess to influence others, and to be influenced themselves, by reason alone. But by urging " the tendency of investigation" and "the spirit of modern thought" in favour of doctrines they cannot support by evi- dence, they appeal to the shadow of an authority which they affect to despise. Every student has undoubted right to require that scientific doctrines, which he is asked and expected to accept as true, should be supported by facts rather than by the authority of tendencies and prophecies. In favour of regarding living beings as mere machines built by force alone, maintained and preserved by force, and even created by force, it is true, very positive statements have been made ; but these have been, for the most part, sup- ported by arguments more ingenious than conclusive. I for one am ready to accept these views, no matter what change OF DEAD AND LIVING. in opinions, beliefs, or hopes that acceptance may involve, provided only they are shown to rest upon facts of obser- vation and experiment. But should mere authority alone induce any conscientious, thoughtful man, who has devoted himself to the study of nature, to believe and confess that a living, moving, growing thing is but a force-created, force- impelled machine? When we watch the lowest forms of living matter under high magnifying powers, do we learn anything to justify us in accepting such a view ? When we ask our confident teachers of the new philosophy to assist us, we get dogmatic assertions, but nothing by way of explanation. Grand words are freely used, but the terms employed are not denned. It is, however, true enough, that men eminent among philosophers, as well as some of the most distinguished living physicists, chemists, and naturalists, have accepted this physical theory of life. They have taught that life is but a mode of ordinary force, and that the living thing differs from the non-living thing, not in quality, or essence, or kind, but merely in degree. They do not attempt to explain the difference between a living thing and the same thing dead. They would perhaps tell us that living and dead are only relative terms ; that there is no absolute difference between the dead and living states ; and that the thing which we call dead, is, after all, only a few degrees less actively living than the thing we say is alive. But is this sort of reasoning convincing, seeing that although matter in the living state may suddenly pass into the dead state, this same matter can never pass back again into the living condition ? Those who advocate this doctrine do not believe in the annihilation of force, when B 2 PROTOPLASM. a living thing suddenly passes from the living into the dead state ; but yet they do not demonstrate the new form or mode which the departing life-energy assumes, or explain to us what in their opinion becomes of it. If the dead thing only differs from the living thing by a few degrees of heat or units of force, why can we not, by supplying more heat or force, prevent dissolution, or cause the actions to go on again after they have once stopped ? In fact this view has been supported by assertions instead of by facts, and of the arguments hitherto advanced in its favour by its most powerful advocates, all are incon- clusive, and some quite unjustifiable. He who chooses may accept upon faith as an article of belief the dogma that all the actions of living beings are due to ordinary forces only but it is absurd to put forward such a conclusion as if it had been proved, or as if it were in the existing state of knowledge capable of proof. So long as the advocates of the physical doctrine of life contented themselves with ridiculing " vitality" as a fiction and a myth, because it could not be made evident to the senses, measured or weighed, or proved scientifically to exist, their position was not easily assailed ; but now when they assert dogmatically that vital force is only a form or mode of ordinary motion, they are bound to show that the assertion rests upon evidence, or it will be regarded by thoughtful men as one of a large num- ber of fanciful hypotheses, advocated only by those who desire to swell the ranks of the teachers and expounders of dogmatic science, which, although pretentious and autho- ritative, must ever be intolerant and unprogressive. LIPE OF A MAGNET. PROFESSOR OWEN'S NEW VIEWS. T)ROFESSOR OWEN has lately avowed his belief in -L the doctrine that the so-called vital forces are really ordinary physical forces. Unlike many advocates, however, he admits that " on one or two points " proof is wanting. But Owen goes much farther than the most advanced micro- scopical observers and scientific investigators. He main- tains that the formation of living beings out of inanimate matter, by the conversion of physical and chemical into vital modes of force, is going on daily and hourly ! The evidence he has adduced in favour of this strange view, it need scarcely be said, is scanty, uncertain, and uncon- vincing ; while a mass of facts and arguments which have been adduced in favour of the opposite conclusion, that every particle of living matter comes from a pre-existing particle, has been unconsciously neglected or purposely ignored. It is very significant that so great a master is unable to suggest a better instance of the analogy which he affirms exists between physical and vital actions than is afforded by magnetism. He says that there is nothing peculiar to living things in their power of selecting certain constituents, because a magnet selects also. Let the reader consider how different is the process called selection in these two cases. A magnet, says Owen, attracts towards it only certain kinds (a certain kind ?) of matter. Is there, then, no difference between selection and attraction ? Nor, he further observes, is death characteristic of things living PROTOPLASM only; for if the steel be unmagnetized, is it not " dead?" Devitalize the sarcode (living amoeba), unmagnetize the steel, and both cease to manifest their respective vital or magnetic phenomena. In that respect both are " defunct." " Only," remarks the same authority, " the steel resists much longer the surrounding decomposing agencies ;" and I would add, but this Owen would regard as a matter of the utmost indifference, you can unmagnetize and remag- netize the magnet as often as you like, but you can only kill the amoeba once, and you can never revitalize it. In answer to my objections to some of his statements, Professor Owen observes that " there are organisms (Vibrio Rotifer, Macrobiotus, &c.) which we can devitalize and revitalize devive and revive many times."* That such organisms can be revived, all will admit, but probably Pro- fessor Owen will be alone in not recognizing any distinction between the words revitalizing and reviving. The animal- cule that can be revived has never been dead, but that which is not dead cannot be revitalized. The difference between the living state and the dead state is absolute, for that which has once lost its life can never regain it. The half-drowned man that can be revived has never been dead. If Owen regards the (apparently) dried animalcule as being " as completely lifeless as is the drowned man whose breath and heat have gone, and whose blood has ceased to circulate," he will not find many to agree with him ; for will not a drop of water resuscitate or revive the one, but who shall revitalize the other ? * "The Monthly Microscopical Journal," No. V, May I, 1869, p. 294. C I LIAR Y A CTION. NOTE ON CILIARY ACTION. In the case of ciliary action we have an example of a movement which, though not strictly a vital movement, like that of the amoeba (see p. 39), is really dependent upon changes which are a direct result of vital phenomena. The cilium itself is not composed of living matter, but its base is certainly in very intimate relation with matter that is alive. The latter may indeed be actually prolonged into the base of the cilium. The vibratile movement is probably due to an alteration taking place in the tension of the fluid which pervades the tissue, induced by the action of the living matter of the cell. The rate of vibration varying according to the rapidity with which the living matter of the cell absorbs nutrient substances, and undergoes conversion into formed matter, or in other words, the rapidity with which the formation of new living matter and the death of the old particles takes place. When ciliary action ceases, we cannot, I think, say that each individual cilium dies, for after all action has ceased a little alkaline fluid will cause the cilium to vibrate again actively. We must not, therefore, infer that the dying cilium has been revived or the dead cilium revitalized by. the liquor potassse, for the fact seems rather to point to the conclusion that the action of the cilium which occurs during life is due to physical changes, and is not a vital action. My friend, Dr. Rutherford, has suggested that the fact of the cessation of movement at the base of the cilium, while the thin part still continues to vibrate, might be advanced as an argument against the views advocated by me in the following pages, and if the cilium itself were composed of living matter, like the body of an amoeba, such an objection would undoubtedly hold : but if, on the other hand, the movement is physical, due to alterations in the currents of fluid through the cell, we should expect that it would continue longer at the apex than at the base, for the simple reason that an impulse which would be sufficient to make the thin free part vibrate freely would be insufficient to move the thicker portion attached to the cell. We cannot say that the cilium dies from base to apex, for the whole vibratile appendage is as destitute of life while it is yet vibrating actively, as after it has ceased to move, and if we could only make fluid flow through the cell after its death interruptedly in the same 8 PROTOPLASM. direction, and with the same force as it is made to flow during life by the action of the living matter, ciliary movement would continue, although the living matter of the cell was actually dead. It is most important to distinguish between vital movements occurring in living matter, and mechanical movements which result from alterations in tension, the flow of currents, &c., consequent upon changes effected by living matter. EXPERIMENTAL ORGANISM. MR. GROVE ON EXPERIMENTAL ORGANISM. MR. GROVE has recently* affirmed that "in a voltaic battery and its effects" we have "the nearest ap- proach man has made to experimental organism :" but surely it should be shown in what particulars a voltaic battery resembles an organism. All organisms come from pre- existing organisms, and all their tissues and organs are formed from or by a little clear, transparent, structureless, moving matter which came from matter like itself, but may increase by appropriating to itself matter having none of its properties or powers. Now, voltaic batteries do not grow or multiply, nor do they evolve themselves out of structureless material, nor, if you give them ever so much pabulum in the shape of the constituents of which they are made, do they appro- priate this. Where too is the chemist who gives what is to be selected ? What then does Mr. Grove mean by asserting that a voltaic battery is the nearest approach man has made to experimental organism ? Has man yet made the slightest approach to experimental organism ? If any apparatus we could contrive developed all possible modes of force motion, heat/ light, electricity, magnetism, chemical action, and any number of others yet to be discovered that apparatus would still present no approach whatever to any organism known. Of course such a thing might he called an organism, just as a watch, or water, or a gas, or an elementary substance may be called a creature, or a worm * "British Medical Journal," May 29, 1869, p. 486. 10 PROTOPLASM. a machine ; but everything that lives every so-called living machine grows of itself, builds itself up, and multiplies, while every non-living machine is made, does not grow, and does not produce machines like itself. Mr. Grove further says that in the human body we have chemical action, electricity, magnetism, heat, light, motion, and possibly other forces " contributing in the most complex manner to sustain that result of combined action which we call life." Here it seems to be affirmed that forces sustain the result of their own combined action, but surely this is only asserting that these forces sustain themselves. Heat, light, electricity, etc., sustain the result of the combined action of heat, light, electricity. It is moreover said that what we call life is the result of the combined action of motion, heat, light, elec- tricity, etc., which are but different forms or modes of one force. But as everybody knows we may have any and all modes of force without life. Life, therefore, involves some-. thing besides force, or is something different from it. Those who teach that life is the sum of all the actions going on in a living body, forget that these actions are not all of the same kind. Of some we know very much, but of the nature of others we know nothing. In every living thing there are physico-chemical actions, which also occur out of the body, and vital actions. These last are peculiar to living beings, and cannot be imitated. In galvanic batteries, and in other arrangements made by man, we may have physico-chemical actions, but never anything at all like vital actions. Of course, authority may decree that henceforth the terms " living galvanic battery" "vital machine" " animated steam engine" shall be employed, and that a man shall be called a "physico-chemical apparatus" or a " kynetic" or "electric machine" but the nature of the things themselves could not be changed in the least degree by authority, however much the names by which they were known were altered. PROTOPLASM. PROTOPLASM. The term "Protoplasm" is now applied to several dif- ferent kinds of matter, to substances differing from one another in the most essential particulars. It seems, there- fore, very desirable that its meaning should be accurately denned by those who employ it, or that it should be super- seded by other words. If certain authorities were asked to define exactly the characters of the matter which they called protoplasm, we should have from those authors defi- nitions applying to things essentially different from one another. Hard and soft, solid and liquid, coloured and colourless, opaque and transparent, granular and destitute of granules, structureless and having structure, moving and incapable of movement, active and passive, contractile and non-contractile, growing and incapable of growth, changing and incapable of change, animate and inanimate, alive and dead, are some of the opposite qualities possessed by different kinds of matter which have nevertheless been called protoplasm. A definition of protoplasm, most probably written by the late Professor Henfrey in " Griffith and Henfrey's Micrographic Dictionary," is as follows : " Protoplasm. The name applied by Mohl to the colourless or yellowish, smooth or granular viscid substance, of nitrogenous con- stitution, which constitutes the formative substance in the contents of vegetable cells, in the condition of gelatinous strata, reticulated threads and nuclear aggregations, &c. It is the same substance as that formerly termed by the ! 2 PROTOPLASM. Germans ' schleim,' which was usually translated in English works by * mucus' or ' mucilage.' " The surface of this mass constituted the " formative protoplasmic layer" which was supposed to take part in the formation of the cellulose wall of the vegetable cell. This was regarded by Von Mohl as a structure of special importance distinct from the cell contents, and it was named by him, in 1844, the " primordial utricle." In cases where protoplasm appears as a simple trans- parent homogeneous substance, several layers have been described, and it has been supposed that these different layers are concerned in different operations. This view has been extended to many forms of protoplasm, and the movements which occur have been attributed to the pre- sence of two or more layers differing in density. Clear, homogeneous protoplasm, it has been said, under- goes vacuolation, and becomes honeycombed, the spaces being rilled with watery matter. In some instances, this change proceeds until mere protoplasmic threads are seen stretched across the cavity. The transparent fluid material occupying the spaces and the intervals between the threads supposed to be the less important matter, and yet it is the living, growing, and moving substance ; while the threads and walls of the spaces are composed of matter which has ceased to manifest these properties matter which no longer lives, and which has been formed from the living matter. But we may fairly ask if this lifeless, passive, formed matter, which cannot move or grow or multiply of itself, which is but a product of the death of protoplasm, is nevertheless to be called by the same name as the living, ENDOPLAST AND PERI PL AST. 13 moving substance which it once was ? If this be so, there ought to be no recognizable difference between matter which is actually alive and the substances which result from its death. So far, then, we have seen that the term protoplasm has been applied to the matter within the primordial utricle of the vegetable cell, to that clear substance which undergoes vacuolation and fibrillation, and to the matter forming the walls of the vacuoles and the threads or fibrillae. Still more recently, Von Mohl's primordial utricle has been called proto- plasm by Professor Huxley, who some years before restricted the term to the matter within the primordial utricle, which matter at that time he regarded as an "accidental anatomi- cal modification" of the endoplast, and of little importance.* The nucleus, and with it the protoplasm, Mr. Huxley thought, exerted no peculiar office, and possessed no meta- bolic power. Now, however, he considers " protoplasm" of the first importance; and under this term includes, I imagine, not only the primordial utricle and the " accidental anatomical modifications " it encloses, but the fully-formed cellulose wall of the vegetable cell. His "endoplast" and "periplastic substance" of 1853 together constitute his "protoplasm" of 1869. The old views are modified, and although the results of researches made during the last few years are scarcely alluded to, the writer evidently has felt that certain changes must be made. So the vacuoles of his periplastic substance become silently tenanted by simple or nucleated protoplasms endowed with " subtle influences" which our author may yet admit to have existed before his * "The Cell Theory," " Med. Chir. Rev.," October, 1853. I 4 PROTOPLASM. periplastic substance was formed. Next he may discover that the endoplast is of the highest importance instead of no importance at all, and then there is an easy step to the doctrine that the periplastic substance is formed by and from the protoplasm which has properties and "subtle influences''' of a remarkable kind, but is not endowed with the absurd fiction of vitality. Max Schultze included under the head of protoplasm the active moving matter forming the sarcode of the Rhizo- pods as well as the substance circulating in the cells of vallisneria, the hairs of the nettle, and other vegetable cells ; and now it is generally admitted that the active, moving matter constituting the white blood-corpuscle, the mucus and pus corpuscle, and other contractile bodies widely dis- tributed, is essentially of the same nature. The move- ments characteristic of this matter have been attributed to an inherent property of contractility ; and this property has been held by some to be characteristic of, and peculiar to, protoplasm. Kiihne considers all contractile material to be protoplasm, and includes the different forms of muscular tissue in the same category as the matter of the amoeba, white blood-corpuscle, &c. But if we apply the term protoplasm to the contracting muscular tissue which exhibits structure, as well as to the living moving matter of the amoeba, &c., in which no structure at all can be made out, it is obvious that these must be regarded as essentially different kinds of protoplasm, 'because they differ in proper- ties which are essential and of the first importance. The contractile movement of the amoeba, white blood-cor- puscle, &c., is a phenomenon very different from the con- KINDS OF PROTOPLASM. traction of muscular tissue. In the first, movements occur in every direction, while the last is characterized by a repe- tition of movement in two definite directions only. And when we come to study the matter which is the seat of these two kinds of movements respectively, we find very im- portant differences. The matter of the amoeba, white blood-corpuscle, &c., grows. It takes up matter unlike itself, and communicates to it its own properties. Now, muscular tissue does not do this. In short, the first kind of matter acts and moves of itself; but the last can only be acted upon and made to move. The first may be compared with a spring, as yet undiscovered, which not only winds itself up and uncoils, but every part of which moves in any direc- tion, and can make new springs out of matter which has none of the properties of a spring j the last with a spring which can only uncoil itself after it has been wound up. Further, the term protoplasm has not been applied only to the matter of which the amoeba, the sarcode of the fora- aninifera, &c., is composed, and that which constitutes the ^white blood-corpuscle and such bodies, but the matter which is gradually assuming the form of tissue has been considered to be of the same nature. The radiating fibres of the caudate nerve-cells of the spinal cord have been termed protoplasm fibres, and the outer part of the nerve- cell with which they are continuous is composed of the same substance. The axis cylinder of the dark-bordered nerve-fibres and the fine ultimate nerve-fibres in peripheral parts have been looked upon as a form of protoplasm ; but it is hardly necessary to remark that, whatever may be the nature of the material of which nerve-fibres and the outer part of nerve-cells are composed 4 it possesses properties PROTOPLASM. very different from those manifested by the amoeba, white blood-corpuscle, etc., and is destitute of the powers which characterize the matter constituting these bodies. Here again we find the term protoplasm applied to different kinds of matter or to matter in very different states. But unfortunately we have by no means exhausted the confusion which has resulted with regard to protoplasm, for the name has been applied also to the outer, hard, dead part of epithelial cells and by implication to all correspond- ing structures. Protoplasm the Physical Basis of Life. In order to convince people that the actions of living beings are not due to any mysterious vitality or vital force or power, but are in fact physical and chemical in their nature, Prof. Huxley gives to matter which is alive, to matter which is dead, and to matter which is completely changed by roasting or boiling, the very same name. The matter of sheep and mutton and man and lobster and egg is the same, and, according to Huxley, one may be transubstantiated into the other. But how ? By " subtle influences," and " under sundry circum- stances," answers this authority. And all these things alive, or dead, or roasted, he tells us are made of protoplasm, and this protoplasm is the physical basis of life, or the basis of physical life* But can the discoverer of "subtle influences" afford to sneer at the fiction of vitality ? By calling things which differ from one another in many qualities by the same name, Huxley seems to think he can annihilate distinctions, enforce identity, and sweep away the difficulties which have impeded the progress of previous philosophers in * The iron basis of the candle, and the basis of the iron candle are expressions evidently interchangeable. PHYSICAL BASIS GF LIFE. their search after unity. Plants and worms and men are all protoplasm, and protoplasm is albuminous matter, and albuminous matter consists of four elements, and these four elements possess certain properties, by which properties all differences between plants and worms and men are to be accounted for. Although Huxley would probably admit that a worm was not a man, he would tell us that by " subtle influences" the one thing might be easily converted into the other, and not by such nonsensical fictions as "vitality," which can neither be weighed, measured, nor conceived.* * But this is not the first time Mr. Huxley has indulged in adroit word-tricks and inapposite illustrations. After referring to the anatomy of the horse, he says, in his "Lectures to Working Men," page II : "Hitherto we have, as it were, been looking at a steam- engine with the fires out, and nothing in the boiler ( ! ) but the body of the living animal is a beautifully-formed machine" And it would be easy to point out in many of his writings, vague remarks of the same sort with similes, calculated rather to mislead than to assist the judgment of students. Take, for example, his far-fetched observations in the first number of the "Academy," page 13, about the kitchen clock, which cries "cuckoo," and shows the phases of the moon, and the death- watch machine, "a learned and intelligent student of its works," ticking like the clock in the clock case. We are told to "substitute 'cosmic vapour ' for ' clock, ' and ' molecules ' for ' works, ' and the application of the argument is obvious." (!) The argument relates to the "forces possessed by the molecules of which the primitive nebulosity of the universe was composed," by the mutual interaction of which forces the whole world living and not living has resulted. " If this be true" (doubt- fully suggests the Professor) " it is no less certain that the existing world lay, potientially, in the cosmic vapour ; and that a sufficient intelligence could, from a knowledge of the properties of the molecules of that vapour, have predicted, say the state of the Fauna of Britain in 1869, with as much certainty as one can say what will happen to the vapour of the breath in a cold winter's day.". (!) These remarks are printed under the heading "SCIENCE AND PHILOSOPHY." C r i8 PROTOPLASM. Some among those who work at and think over these matters doubt if many of Prof. Huxley's assertions are at all justified by his facts, and many are unable to accept argu- ments which by him seem to have been considered quite conclusive. I shall therefore venture to draw attention to some of the views he has recently expressed in his paper, " On the Physical Basis of Life," published in the " Fort- nightly Review", February ist, 1869. Up to this time all observers have agreed in opinion that the cell or elementary part of the fully-formed organism consists of different kinds of matter, and it has been sup- posed that distinct offices were performed by some of these. They have been variously named. Cell-wall, cell-contents, nucleus, nucleolus, periplast, endoplast, primordial utricle, protoplasm, living matter and formed matter, are not all the terms that have been proposed. I think Professor Huxley is the first observer who has spoken of the cell in its entirety as a mass of protoplasm, and the only one who has ever asserted that any tissue in nature is composed through- out of matter which can properly be regarded as one in kind. This view is quite incompatible with many facts, some of which have been alluded to by Mr. Huxley him- self.* I doubt if in the whole range of modem science it would be possible to find an assertion more at variance with facts familiar to physiologists than the statement that " beast and fowl, reptile and fish, mollusk, worm, and * "The original endoplast of the embryo cell," Huxley says, in 1853, "has grown and divided into all the endoplasts of the adult," and "the original periplast has grown at a corresponding rate, and has formed one continuous and connected envelope from the very first." HUXLETS PROTOPLASM. polype," are composed of " masses of protoplasm with a nucleus," unless it be that still more extravagant assertion that what is ordinarily termed a cell or elementary part is a mass of protoplasm ; for can anything be more unlike the semi-fluid, active, moving matter of amoeba protoplasm, than the hard, dry, passive, external part of a cuticular cell or of an elementary part of bone ? I cannot forbear quoting in this place the following passage, which certainly requires explanation. After stating that the substance of a colourless blood-corpuscle is an active mass of protoplasm, Mr. Huxley remarks that " iinder sundry circumstances the corpuscle dies (!) and becomes distended into a round mass, in the midst of which is seen a smaller spherical body, which existed, but was more or less hidden in the living corpuscle, and is called its nucleus. Corpuscles of essentially similar structure are to be found in the skin, in the lining of the mouth, and scattered through the whole framework of the body" Now, what can be meant by a white blood-corpuscle dying and becoming dis- tended into a round mass under sundry circumstances? Mr. Huxley goes on to say that at an early period of deve- lopment the organism is " nothing but an aggregation of such corpuscles," that is, of corpuscles (elementary parts or cells) like those " found in the skin, in the lining of the mouth, and scattered through the whole framework of the body." This assertion is incorrect, inasmuch as the corpuscles in the embryo consist almost entirely of (living) matter like the white blood-corpuscle, while those of which the skin (cuticle) and most of the tissues of the adult are composed consist principally of formed matter with a very c 2 * 20 PROTOPLASM. little of the other (living) matter, and the oldest particles of cuticle are entirely composed of hard formed matter. Here, as in other cases referred to by Huxley, no distinction is drawn between that which is living, growing, and forming; and that which has been formed and is destitute of all powers of life and growth. No distinction between living matter and lifeless matter ! Both are confused together under the term "pro- toplasm," for which might be substituted "organic matter" or " albuminous matter." Huxley terms the particles of epithelium of the cuticle and of mucous membranes, masses of protoplasm. He says beasts and fowls, reptiles and fishes, are all composed of structural units of the same character. Now, this mass of protoplasm, this unit, con- sists partly of lifeless and partly of living matter. The outer part, which may be dry and hard, and is lifeless, may be undergoing disintegration, and is perhaps being taken up by other living organisms, but is nevertheless, according to this view, just as much protoplasm as the living, growing, moving matter itself. It does not signify how many dif- ferent things may be comprised in the cell or elementary part, in what essentially different states these things may be, how different parts may differ in properties they constitute protoplasm. A muscle is protoplasm ; nerve is protoplasm ; bone, hair, and shell are protoplasm ; a lirnb is protoplasm; the whole body is protoplasm, and of course bone, hair, shell, etc., are as much "the physical basis of life" as albuminous matter and roast mutton. But surely it would be less incorrect to speak of such "protoplasms" as the physical basis of death or the physical basis of roast, than to call dead and roasted matter the physical basis of WHA T IS PRO TOPLASM ? 2 1 life. No anatomical investigation is necessary to enable us to detect this substance. Every beast, fowl, reptile, worm, or polyp that we see is protoplasm. Everything that lives or has lived is protoplasm, variously modified.* Mr. Huxley seems to maintain that protoplasm may be killed and dried, roasted and boiled, or otherwise altered, and yet remain protoplasm ; but his " protoplasm" is after all only albuminoid or protein matter. t Huxley says lobster- protoplasm may be converted into human protoplasm, and the latter again turned into living lobster. But the statement is incorrect; because, in the process of assimilation "pro- toplasm" is entirely disintegrated, and is not converted into the new tissue in the form of protoplasm at all ; and he must permit me to remark that sheep cannot be transub- stantiated into man, even by " subtle influences," nor can dead protoplasm be converted into living protoplasm, or a dead sheep into a living man. And what is gained by calling the matter of dead roast mutton and of a living growing sheep by the same name ? If the last is the physical basis of life one does not see how the first can be so too, unless roast mutton and living sheep are identical ; but surely Mr. Huxley does not really mean to assert this. It is remarkable that Huxley himself, some sixteen years * The term "variously modified" perhaps includes the terms living and dead } and, according to Mr. Huxley, expresses with sufficient exactness the difference between the living and dead states. + Mr. Huxley says, "all protoplasm is proteinaceous ; or, as the white or albumen of an egg is one of the commonest examples of a nearly pure protein matter, we may say that all living matter is more or less albuminoid." If the white of an egg is living matter, why not its shell ? 22 PROTOPLASM. ago, drew a distinction between living and non-living matter, which he now, without any explanation, utterly ignores. He remarked that the stone, the gas, the crystal, had an inertia, and tended to remain as they were unless some ex- ternal influence affected them ; but that living things were characterized by the very opposite tendencies. He referred also to " the faculty of pursuing their own course" and the " inherent law of change in living beings." In 1853, the same authority actually found fault with those who at- tempted to reduce life to " mere attractions and repulsions," and considered physiology " simply as a complex branch of mere physics." He also remarked that "vitality is a pro- perty inherent in certain kinds of matter." Bathybius. I will now draw attention to a fanciful form of marine protoplasm, supposed to be very widely extended at great depths, which has been much discussed of late, and concerning the nature of which much difference of opinion is entertained. From the protoplasm of the amoeba and certain forms of foraminifera. we pass, it is said, to larger and more extended sheets of this substance, included under the head of " urschleim," and constituting the organisms of the simplest animated beings, which have been included by Haeckel in the genus Moner. It would be wrong to omit all mention of this subject, as it is very interesting and of great importance, although I have not given much attention to it. I shall therefore quote the observations of others so far as they appear to me to bear upon the consideration of the nature of protoplasm. In the "Microscopical Journal" for October, 1868, is a BATHYBIUS. 23 memoir by Professor Huxley, " On some Organisms living at great Depths in the North Atlantic Ocean," in which he states that the stickiness of the deep-sea mud is due to " innumerable lumps of a transparent gelatinous substance," each lump consisting of granules, coccoliths, and foreign bodies, embedded in a " transparent, colourless, and struc- tureless matrix." The granules form heaps which are some- times the To-Vo tn of an inch or more in diameter. The "granule" is a rounded or oval disc, which is stained yellow by iodine, and is dissolved by acetic acid. " The granule heaps and the transparent gelatinous matter in which they are embedded represent masses of protoplasm." One of the masses of this deep-sea "urschleim" may be regarded as a new form of the simplest animated beings (Moner), and Huxley proposes to call it Bathybius* The " Discolithi and the Cyatholithi" some of which resemble the " granules," are said to bear the same relation to the protoplasm of Bathybius as the spicula of sponges do to the soft parts of those animals ; but it must be borne in mind that the spicula of sponges are imbedded in a matrix, which is formed by and contains, besides the spicula, small masses of living or germinal matter, which have been ignored, although the matrix is produced and the form of the spicula deter- * The idea of the existence of huge continuous masses of living matter of enormous extent, is most fanciful and improbable. It appears to be opposed to well ascertained facts. So far from living matter growing to form very large collections, it divides in almost all known instances before it reaches the diameter even of 3^ of an inch. I think that the phenomena essential to living matter are only possible in minute masses separated from one another, so that each may be supplied with nutrient materials. See "Of Life," p. 67. 24 PROTOPLASM. mined by them. As in other cases, this matrix, with the living matter included, constitutes " protoplasm." Bathybius has been fancifully described as " a vast sheet of living matter (!) enveloping the whole earth beneath the seas," composed of molecules whose organizing tendencies will be shown after the lapse of several thousand years in the Fauna and Flora of the period of which the unscientific cannot now form the remotest conception. But it is surely a consoling thought, and one eminently calculated to confirm our faith in the infallibility of the new philosophy, to re- member the remarkable prophecy that the successful neo- biologist is not only to render evident the wonderful proper- ties now dormant in the existing Bathybius, but as soon as he shall have succeeded in demonstrating to us the properties of the molecules which once formed the primitive nebulosity, he will be able to predict the exact state of the Fauna and Flora of Middlesex in the year 5069, and with as much certainty as he can now tell us what will happen if exactly one thousand grains of proteid organic matter be exposed, in an atmosphere of carbonic acid to a temperature of 25 during the space of two hours. Dr. Wallictts Observations. Dr. Wallich has, it need scarcely be said, arrived at a very different conclusion. In a paper " On the Vital Functions of the Deep-sea Protozoa," published in No. I. of the " Monthly Microscopical Journal," January, 1869, this observer, who has long been engaged in this and kindred studies, states that the coccoliths and cocco- spheres stand in no direct relation to the protoplasm sub- stance referred to by Huxley under the name of Bathybius. The former are derived from their parent coccospheres, DR. WALLICITS VIEWS. 25 which are independent structures altogether. " Bathybius" instead of being a widely-extending sheet of living protoplasm which grows at the expense of inorganic elements, is rather to be regarded as a complex mass of slime with many foreign bodies and the debris of living organisms which have passed away. Numerous minute living forms are, however, still found on it. Dr. Wallich is of opinion that each coccosphere is just as much an independent structure at Thalassicolla or Col- lospJmra, and that, as in other cases, " nutrition is effected by a vital act," which enables the organism to extract from the surrounding medium the elements adapted for its nutri- tion. These are at length converted into its sarcode and shell material. In fact, in these lowest simplest forms, we find evidence of the working of an inherent vital power, and in them nutrition seems to be conducted upon the same principles as in the highest and most complex beings. In all cases the process involves, besides physical and chemical changes, purely vital actions, which cannot be imitated, and which cannot be explained by Physics and Chemistry. Chemistry of Protoplasm. From what has been said already, it must be obvious that the chemistry of the complex matter now termed protoplasm, embraces, i, the chemistry of the formed matter, and 2, the chemistry of the active, living, growing, matter, of an organism. By chemical analysis we can ascertain the composition of the first, and can learn many facts concerning its elementary chemical characters; but it is obvious that chemistry can teach us little with regard to the composition of the living matter, for we kill it when we attempt to analyze it ; and 26 PROTOPLASM. in truth we analyze not the living matter, but the sub- stances resulting from its death. Of course any one may say that the inanimate substances he obtains were the actual things of which the living matter was composed, but it is a mere assertion, for the bodies in question cannot be detected in the matter while it is actually alive; and when obtained they do not possess the properties or powers characteristic of the living matter.* What, therefore, can be gained by asserting that these things constitute living matter? What is the use of trying to make people believe and con- fess that there is no difference between a living thing and the same thing dead, when it is clearly possible that there may be the very greatest difference ? And I must not omit to notice here a remark made by Mr. Herbert Spencer, which illustrates the extraordinary opinion entertained by him concerning the difference be- tween living, growing, active, matter, and perfectly lifeless matter. " On the other hand (he says) the microscope has traced down organisms to simpler and simpler forms, until, in the Protogenes of Professor Haeckel there has been reached a type distinguishable from a fragment of albumen only by its finely granular character""^ Mr. Herbert Spencer should prepare a solution of albumen and a solution of " proto- * " In the last place, Mr. Huxley's analysis is an analysis of dead protoplasm, and indecisive, consequently, for that which lives. Mr. Huxley betrays sensitiveness in advance of this objection ; for he seeks to rise above the sensitiveness and the objection at once by styling the latter 'frivolous.'" "As regards Protoplasm in relation to Professor Huxley's Essay on the Physical Basis of Life," by J. H. Stirling, LL.D., F.R.C.S. Edinburgh, Blackwood and Sons, October, 1869. f "The Principles of Psychology," p. 137. FORCE AND FORM. 27 genes," and by careful evaporation he might obtain two extracts not distinguishable from one another. Both would exhibit a " finely granular character," and thus the important fact that there was no difference whatever between the inanimate albumen and the inanimate " protogenes " would be demonstrated. And as every one is now prepared to admit that there is no difference between dead "proto- genes" and living "protogenes," we must of course accept the conclusion that the lowest forms of life are but forms of albumen. In this way " the chasm between the inorganic and the organic is being filled up ! " "Properties" of Matter. Here are some specimens of the dogmatic assertions which have been advanced in place of facts and arguments in favour of the physico- chemical doctrines. "The difference between a crystal of calcspar and amorphous carbonate of lime corre- sponds to the difference between living matter and the matter which results from its death. Just as by chemical analysis we learn the composition of calc spar, so by chemical analysis we ascertain the composition of living matter. It is not probable that there is any real differ- ence in the nature of the molecular forces which compel the carbonate of lime to assume and retain the crystalline form, and those which cause the albuminoid matter to move and grow, select and form and maintain its particles in a state of incessant motion. The property of crystallising is to crystallisable matter what the vital property is to albu- minoid matter (protoplasm). The crystalline form corre- sponds to the organic form, and its internal structure to tissue structure. Crystalline force being a property of matter, 28 PROTOPLASM. vital force is but a property of matter." It might be objected that crystalline force keeps particles still and compels them to assume a constant form, while vital force prevents them from assuming any definite form at all and keeps them moving,; -form being assumed only when the matter is with- drawn from the influence of the vital force ; but these and any other objections raised to the physical theory of life are accounted absurd and frivolous. It has been asserted posi- tively that there is but one true theory of life the physical theory. Its advocates seem to think that any objections raised to this ought not to be listened to, because they assert prophetically that by the rapid advance of molecular physics, the truth of their theory will some day be fully established. Aquosity and Vitality. The properties possessed by in- organic compounds are supposed to be due in some way to the properties of the elements of which they consist. Thus it has been remarked that the properties of water result from the properties of its constituent gases, and are not due to " aquosity," as if any reasonable man would think of referring the properties of water to such a " subtle in- fluence" as " aquosity." It has been argued that since the properties of water are due to its gases and not to aquosity, the properties of protoplasm are due to its elements, Oxygen, Hydrogen, Nitrogen, and Carbon, and not to vitality. But the cases are by no means parallel. Of water there is but one kind.* Of protoplasm there are kinds innumerable. The constituent elements of the same particle of water may * A hostile critic has discovered that there are at least two kinds, dirty water and clean water ! VITAL PROPERTIES. 29 be separated and recombined again and again as many times as we please; but the elements of protoplasm once separated from one another, can never be combined again to form any kind of protoplasm. But further, every kind of protoplasm differs from every other kind most remarkably in the results of its living, one producing man, another dog, a third butterfly, a fourth amoeba, and so on. Now, what can be more absurd than to suggest that the properties of man, dog, butterfly, and amoeba are due not to vitality, but to the constituent elements, or to the properties of the molecules of their tissues ? Do the properties of the elements of dog differ sufficiently from those of the ele- ments of man, to account for the differences between dog and man. Have we not rather reason to infer an approximation towards identity of composition in the living matter, with marvellous difference in the results of the vital actions ? How, then, can the differences be due to the ordinary properties of the elements ? Wonderful properties have indeed to be discovered in connection with elements before we can refer the differences in property of living beings compounded of them to the properties of the ele- ments themselves. The argument advanced against vitality, as far as it rests upon the non-existence of aquosity, is utterly worthless, and it is astonishing that any writer who gave his readers credit for moderate intelligence should have adduced it at all. To sum up in few words. The term protoplasm has been applied to the viscid nitrogenous substance within the primordial utricle of the vegetable cell and to the threads and filaments formed in this matter; to the primordial 30 PROTOPLASM. utricle itself; to this and the substances which it encloses; and to all these things, together with the cellulose wall ; to the matter composing the sarcode of the foraminifera ; to that which constitutes the amoeba, white blood-corpuscle, and other naked masses of germinal matter ; to the matter between the so-called nucleus and muscular tissue, and to the contractile matter itself; to everything which exhibits contractility ; to nerve-fibres, and to other structures pos- sessing remarkable endowments ; to the soft matter within an elementary part, as a cell of epithelium ; to the hard external part of such a cell; to the entire epithelial cell. Inanimate albuminous matter has been regarded as protoplasm. Living things have been spoken of as masses of protoplasm ; the same things dead have been said to be protoplasm. If the matter be boiled or roasted, it is still protoplasm ; and there seems no reason why it should not be dissolved, and yet retain its name protoplasm. It is therefore very difficult to see whit advantage is to be gained by the use of the word " protoplasm." If we call a cell a protoplasm, and an egg a protoplasm, and a sheep a protoplasm, and a man a protoplasm, we do not therefore get a clearer idea of any one of them than we had before, while on the other hand the words cell, egg, sheep, man, are distinctive, short, and generally understood. There would be terrible risk of very different living things being con- founded, if they were all called " protoplasms." Notwithstanding the clever and subtle arguments which have been advanced in its favour, and repeated over and over again in almost every possible form, the new doctrine PROPERTIES OF LIVING BEINGS. of life has exerted very little influence. It is absurd to expect that thoughtful persons will be convinced that vital phenonema are physical and chemical phenomena, simply by an authoritative assertion that they are so ; and no matter how energetically the doctrine may be advocated, it will not be received unless it is proved to be founded upon facts. In spite of all that has been said, the chemist has taught us little concerning the nature of the changes which take place when pabulum becomes totally changed and converted into living matter, or when the latter gives rise to some peculiar kind of formed matter. He has shown us, it is true, that certain substances result- ing in the organism during the disintegration of formed matter may be prepared artificially in the laboratory but he knows as well as the physiologist, that their formation in the organism is conducted upon totally different principles, of the nature of which all are entirely ignorant. And it is childish to attempt, as some have done, to hide our igno- rance by referring the actions to subtle influences, cell- laboratories, and molecular machinery, when every one knows there is nothing like a laboratory or machinery in any molecule or cell in any organism. The different forms and properties of living beings can only be explained by supposing the influence of force dif- ferent from ordinary forces acting upon the matter of which they are composed, or upon the existence of properties, other than the inorganic properties, transmitted or handed down from pre-existing matter having similar, though, perhaps, not identical properties. These vital properties seem to be super- added to matter temporarily, and are not, like the former, 32 PROTOPLASM. permanent endowments. The one class of properties remains permanently attached to the elements of matter ; the other may be once removed, but can never be restored. The material properties belong to the matter, whether living or dead ; but where are the vital properties in the dead material? If physicists and chemists would restore to life that which is dead, we should all believe in the doctrine they teach. So long as they tell us their investigations only tend towards such a consummation, they must expect a few to be wanting in faith. " You may bury me as you choose, if you can only catch me. But you will not understand me when I tell you that I, Socrates, who am now speaking, shall not remain with you after having drunk the poison, but shall depart to some of the enjoyments of the blest. You must not talk about burying or burning Socrates, as if I were suffering some terrible operation. Such language is inauspicious and depressing to our minds. Keep up your courage and talk only of burying the body of Socrates ; conduct the burial as you think best, and most decent. "Plato, Phcedon, p. 115, C-D. ; Grate's Plato, vol. //., p. 193. GERMINAL OR LINING MATTER, AND FORMED MATTER. )THING that lives is alive in every part. Pro- bably no one would maintain that the shell of an oyster or mussel, for example, was, like the living moving mollusk itself, in a living state. Never- theless, the shell grows, but upon careful examination it will be found that growth is restricted to certain points. It grows at the free edge and upon the inner surface, and thus increases in dimensions. By far the greater part of the shell, therefore, is as lifeless while it yet remains connected with the living animal as after it has been preserved in our cabinet. The new matter which is added to it by the living creature is prepared and formed through the instrumentality of living matter. In man, and the higher animals, the free portions of the nails and hair, the outer part of the cuticle, and a por- tion of the dental tissues, are evidently lifeless. But the waste and removal of some of these is compensated for to a great extent by the addition of new matter by living particles. Of the internal tissues a great part is also in a non-living condition, and it therefore becomes necessary in all in- quiries concerning the nature of the changes and actions taking place in living beings, to determine at the outset, what parts of these beings are in a living state, and what D 34 PROTOPLASM. parts have already ceased to live, although they may per- form important service of a passive kind, and be connected with the matter that is actually alive. Even in the smallest organisms which exhibit the simplest characters, as well as in every texture of the most highly complex beings, we can demonstrate two kinds of matter, differing in most remarkable particulars from one another ; or perhaps it would be more correct to say, matter in two different states, manifesting different properties and exhibiting differences in appearance, chemical composition, &c., and physical characters. This distinction is essential and invariable, and although by calling everything entering into the composition of a living being by the same name, all differences of state, structure, and composition may be ignored, these cannot be destroyed; and every one who really desires to learn anything about the structure, growth, and actions of living things will find himself compelled to admit these differences, and will at once proceed to investigate how they are to be accounted for. In my lectures at the Royal College of Physicians, in the spring of 1860, I demonstrated in the tissues of plants, animals, and man in health and disease, matter in the two different states above referred to, and I showed that every normal and abnormal cell or elemental unit of every tissue capable of growth, or possessing formative power, invariably consisted of matter in these two states or conditions : i. Living, active, formative ; 2. Lifeless, passive, formed. In my preparations these two different forms of matter are at once distinguished, the first being artificially coloured with carmine, while the matter in the last condition remains untinged. LIVING AND FORMED MATTER. 35 As investigation proceeded, I became more and more convinced of the importance of the distinction I had drawn, and it was proved that the matter coloured, which had been considered by many authors to be of little importance, was really in the living, active, growing state. It was shown that upon it all growth, multiplication, conversion, formation, and, in short, life depends. And in many instances when death occurred, the matter in the first state alone changed, while the last remained unaltered. The first was alone capable of dying, for, in fact, this only had been alive. On the other hand, the matter in the second condition, although it may possess very remarkable properties, and have a highly complex chemical composition never grows or multiplies. It never converts or forms. New matter may be added to it, but it cannot convert matter of itself. In short, it does not live. Lastly, facts and arguments were advanced which showed that all matter in the last or formed state was once in the first or living state, so that the properties it acquired and the characters it possessed as formed matter were to be attributed to the changes which had been brought about while the matter existed in the antecedent or living state. There is reason to think that not even the smallest living particle seen under the i -501)1 of an inch objective consists of matter in the same state in every part, for it consists of i, living matter; 2, matter formed from this; and 3, pabulum, which i takes up. The matter in the first state is alone concerned in develop- ment, and the production of those materials which ultimately take the form of tissue, secretion, deposit, as the case may be. It alone possesses the power of growth and of producing D 2 3 6 PROTOPLASM. matter like itself out of materials differing from it materially in composition, properties, and powers. I therefore called it germinal ox living matter, to distinguish it from Reformed ma- terial, which is in all cases destitute of these properties. The difference between germinal or living matter and the pabu- lum which nourishes it, on the one hand, and the formed material which is produced by it, on the other, is, I believe, absolute. The pabulum does not shade by imperceptible gradations into the living matter, and this latter into the formed material ; but the passage from one state into the other is sudden and abrupt, although there may be much living matter mixed with little lifeless matter or vice versa. The ultimate particles of matter pass from the lifeless into the living state, and from the latter into the dead state, suddenly. Matter cannot be said to half-live or half-die. It is either dead or living, animate or inanimate; and formed matter has ceased to live. Matter may be more or less perfectly or imperfectly formed, and formed matter may differ in hardness, colour, consistence, and a number of other qualities, and it may gradually pass from one state into the other ; but nothing of this kind is observed in the case of the germinal matter. The formed matter may possess very remarkable properties, and may undergo various physical and chemical changes under the influence of heat, moisture, oxygen, &c. It may permit some fluids to permeate it, and may interfere with the passage of others. It may contribute to the stability of the organism, and perform a variety of important functions, but it cannot take the place of the germinal or living matter, nor in many cases does it continue to exhibit its characteristic LIVING AND FORMED MATTER, AND PABULUM. 37 properties after the death of the germinal matter belonging to it has occurred. The terms Living Matter, Formed Matter, and Pabulum. Since many kinds of formed matter had been called protoplasm as well as the matter which is in the living state, I should have been wrong if I had employed that term in speaking of 'living matter. From the time when my re- searches were made to the present, the confusion in the use of the word protoplasm has continued to increase, until every form of tissue has been thus called, as well as every kind of germinal or living matter. And it would only add to the exist- ing confusion if any attempt were now made again to alter the meaning of the word ; so that, upon the whole, it seems better to use the more simple term living or germinal matter to denote the growing, active, moving substance which is peculiar to everything living, and which is alone concerned in the multiplication, growth, and formation of all tissues and organisms. Living or germinal matter, formed matter, and pabulum, are the only terms required in describing the development, formation, and growth of any tissue, the production of secretions, and other phenomena peculiar to living things ; and I have ventured to suggest the use of these terms, because they have the advantage of being simple. They can be accurately denned and distinguished from other terms. They are short, expressive, and can be remembered without difficulty, and there is certainly an absence of that mysteriousness which hangs about so many of our scientific words in ordinary use, and greatly adds to the difficulties experienced by the student. 38 PROTOPLASM. General Characters of Germinal Matter. The characters of germinal matter may be studied in the lowest organisms in existence, and in plants, as well as in man and the higher animals. Germinal or living matter is always transparent, colourless, and, as far as can be ascertained by examination with the highest powers, perfectly structureless, and it exhibits these same characters at every period of existence. The germinal matter of the thallus of the growing sugar fungus exists in considerable quantity, and is well adapted for examination. The growing extremity of the branch is rounded, and here the process of growth is going on with great activity. When the operation of staining has been conducted successfully, these growing extremities are more deeply stained than the rest of the germinal matter. A similar fact is observed if one of the placental tufts is submitted to examination. At the extreme end of each tuft is a mass of germinal matter which is darkly stained by the carmine fluid. Behind this, and growing towards it, is the vascular loop ; but as the tufts grow, the mass of formless, structureless germinal matter at the end of each moves onwards, the vessels being developed in its wake. This formless living matter moves forwards and burrows, as it were, into the nutrient pabulum, some of which it takes up as it moves on. It is not pushed from behind, but it moves forward of its own accord. In a similar manner the advancing fungus bores its way into the material upon which it feeds, and the root filament insinuates itself into interstices between the particles of the soil. In the hair, the germinal matter grows and multiplies at the base or bulb, pushing the firm and already formed tissue AMCEBA. 39 before it. In the first case, the germinal matter is increasing at the extremity of a filament which it spins behind it as it moves on ; in the last, the tissue already formed is pushed on by the production of new texture in its rear. The ex- tremity of the hair is its oldest part, and nearest to the root is the tissue which was most recently formed. But whe- ther germinal matter moves on in its entirety, or, advancing from a fixed point, forms a filament, a tube, or other structure which accumulates behind it, or itself remains stationary while the products of formation are forced on- wards in one direction, or outwards in all, the nature of the force exerted is the same, and due to the marvellous power which one part of a living mass possesses of moving in advance of another portion of the same, as may be actually seen to occur in the humble amceba, in the mucus- or in the white blood- corpuscle from man's organism, as well as in the pus corpuscle formed in disease. Amoeba. Among the simplest living things known to us are the amoebae, which might be almost described as animate masses of perfectly transparent moving matter. Amoebae, fig. 4, pi. II., can be obtained for examination by placing a small fragment of animal or vegetable matter in a little water in a wine-glass, and leaving it in the light part of a warm room for a few days. I have found it convenient to introduce a few filaments of cotton wool into the water. The amoebae collect amongst the fibres, which prevent them from being crushed by the pressure of the thin glass cover. The delicate material of which these simple creatures are composed exhibits no indications of actual structure, although it is darker and more granular in some parts than 4 o PROTOPLASM. in others. The germinal matter of all organisms, and of the tissues and organs of each organism, exhibits precisely the same characters. It lives, and grows, and forms in the same way, although the conditions under which the phe- nomena of life growth and formation are carried on differ very much in different kinds of germinal matter. A tem- perature at which one kind will live and grow actively will be fatal to many other kinds. So, too, as regards pabulum, substances which are appropriated by one form of ger- minal matter will act as a poison to another. But the way in which the germinal matter moves, divides and subdivides, grows, and undergoes conversion into tissue, is the same in all. Many remarkable differences in structure, properties, action, and character, are associated with close similarity, if not actual identity of composition. These must, there- fore, be attributed not to properties of elements, physical forces, chemical affinities, or other characters which we can ascertain or estimate by physical examination, but to a difference in vital power which is inherited, which we cannot isolate, but which it would be unreasonable to ignore. On Vital Movements. One characteristic of every kind of living matter is spontaneous movement. This, unlike the movement of any kind of non-living matter yet dis- covered, occurs in all directions, and seems to depend upon changes in the matter itself, rather than upon impulses communicated to the particles from without. I have been able to watch the movements of small amoebae, which multiplied freely without first reaching the size of the ordinary individuals. I have represented the VITAL MOVEMENTS. 41 appearance under a magnifying power of 5,000 diameters of some of the most minute amoebae I have been able to discover. (Plate II, fig. 3.) Several of these were less than 100 1 ooTJ th of an inch in diameter, and yet were in a state of most active movement. The alteration in form was very rapid, and the different tints in the different parts of the moving mass, resulting from alterations in thickness, were most distinctly observed. The living bodies might, in fact, be described as consisting of minute portions of very transparent material, exhibiting the most active movements in various directions, in every part, and capable of absorbing nutrient materials from the surrounding medium. A portion which was at one moment at the lowest point of the mass would pass in an instant to the highest part. In these movements one part seemed, as it were, to pass through other parts, while the whole mass moved now in one, now in another direction, and movements in different parts of the mass occurred in directions different from that in which the whole was moving. What movements in lifeless matter can be compared with these ? The movements above described continue as long as the external conditions remain favourable ; but, if these alter and the amoeba be exposed to the influence of unfavourable circumstances as altered pabulum, cold, &c. the move- ments become very slow, and then cease altogether. The organism becomes spherical, and the trace of soft formed material upon the surface increases until a firm protective covering, envelope, or cell-wall results. In this way the life of the germinal matter is preserved until the return of favourable conditions, when the living matter emerges from 42 PROTOPLASM. its prison, grows, and soon gives rise to a colony of new amoebae, which exhibit the characteristic movements. Mucus Corpuscle. Every one knows that upon the surface of the mucous membrane of the air-passages, even in health, there is a small quantity of a soft viscid matter generally termed mucus. This mucus, said to be secreted by the mucous membrane, contains certain oval or spherical bodies or corpuscles, which are transparent and granular. From the changes of form which take place in them, it is certain that the matter of which they are composed is almost diffluent. These corpuscles or cells are mucus cor- puscles, but they have no cell-wall. They are separated from each other by, and are embedded in, a more or less transparent, viscid, tenacious substance formed by the cor- puscles, and termed mucus. (Plate II, fig. i.) No language could convey a correct idea of the changes which may be seen to take place in the form of the living mucus or pus corpuscle j every part of the substance of a corpuscle exhibits distinct alterations within a few seconds. The material which was in one part may move to another part. Not only does the position of the component particles alter with respect to one another, but it never remains the same. There is no alternation of movements. Were it possible to take hundreds of photographs at the briefest intervals, no two would be exactly alike, nor would they exhibit different gradations of the same change ; nor is it possible to represent the movements with any degree of accuracy by drawings, because the outline is changing in many parts at the same moment. I have seen an entire corpuscle move onwards in one definite direction for a dis- PLATE II. GERMINAL OR LIVING MATTER. One of the living mucns corpr.KclP! 7'pprfsentPcl in T''iii. 1, iTiai^nified by the g\T = '.'WXi diameters, showing alterations in form during <>\\>* us from tli- 3 trnrhon during life, Very TTiimUe living am;i'l,rr>, mafinifiM COM inute partirle of iprminal maltr-r from living x asoo. x -000. a pae 43 VITAL MOVEMENTS. 43 tance equal to its own length or more. Protrusions would occur principally at one end, and the general mass would gradually follow. Again, protrusions would take place in the same direction, and slowly the remainder of the cor- puscle would be drawn onwards, until the whole had been removed from the place it originally occupied, and would advance onward for a short distance in the mucus in which it was embedded. From the first protrusions smaller protrusions very often occur, and these gradually become pear-shaped, remaining attached by a narrow stem, and in a few seconds perhaps again become absorbed into the general mass. From time to time, however, some of the small spherical portions are detached from the parent mass, and become independent masses of germinal matter, which grow until they become ordinary mucus corpuscles. (PI. II, fig. 2.) Are these phenomena, I would ask, at all like any known to occur in lifeless material ? The component particles evidently alter their positions in a most remarkable manner. One particle may move in advance of another, or round another. A portion may move into or round another portion. A bulging may occur at one point of the circumference, or at ten or twenty different points at the same moment. The moving power evidently resides in every particle of a very transparent, invariably colourless, and structureless material. By the very highest powers only an indication of minute spherical particles can be discerned. Because molecules have been seen in some of the masses of moving matter, the motion has been attributed to these. It is true the molecules do move, but the living transparent material in which they are situated 44 PROTOPLASM. moves first, and the molecules flow into the extended portion. The movements cannot, therefore, be ordinary molecular movements. It has been said that the movements may result from diffusion, but what diffusion or other movement with which we are acquainted at all resembles these ? Observers have ascribed them to a difference in density of different parts, but who has been able to produce such movements by preparing fluids of different density ? But further, in the case of the living matter, these supposed fluids of different density make themselves and retain their differences in density. Nor is it any explanation of the movements to attribute them to inherent " irritability," unless we can show in what this irritability essentially consists. Some dismiss the matter by saying that the movements depend upon the property of " contractility," but the movements of germinal matter are totally distinct from contractility, as manifested by muscular tissue ; since they take place in every direction, and every movement differs from the rest, while in muscular contraction there is a constant repetition of changes taking place alternately in directions at right angles to one another ; and hence, if the movements in question be due to contractility, it is necessary to assume two very different kinds of contractile property.* The movements in the mucus corpuscle and in the amoeba, are of the same nature as those which occur in the germinal matter of many plants, as is easily observed in the cells of the leaves of the vallisneria or the anacharis, in the chara, and in the hairs of the flower of Tradescantia ; and the * See my paper "On Contractility as distinguished from purely vital movements." "Trans. Mic. Soc." 1866. NEW LIVING CENTRES. 45 appearance of the living matter under very high powers is precisely the same in all cases. Similar movements certainly occur in pus, and in cancer, and probably in every kind of living matter in health and in disease. (PI. II, figs. 5 and 6.) In some instances the movements continue for many hours after the living matter has been removed from the surface upon which it grew. In other cases, and we shall not be surprised that this should be so in the higher animals, death occurs the instant the conditions under which the living matter exists are but slightly modified. In many instances no movements can be seen, but the evidence of their occur- rence is almost as decided as if they were visible, for we discern certain results which can only be explained by the occurrence of such movements as have been referred to. I have often tried to persuade the physicist, who has so long prophesied the existence of molecular machinery in living beings, to seek for it in the "colourless, structureless, 1 ' germinal matter. But he contents himself with asserting that such machinery exists, although he cannot see it or make it evident to himself or others. Of New Centres Nuclei and Nucleoli. In many masses of germinal matter a smaller spherical portion often ap- pearing a mere point is observed, and in some cases this divides before the division of the parent mass takes places. This, however, is not necessary to the process, for division takes place in cases in which no such bodies are to be seen, and it frequently happens that one or more of these smaller spots or spherical masses may appear in its substance, after a portion of germinal matter has been detached from the parent mass. These are to be regarded 46 PROTOPLASM. as new centres composed of living matter. Within these a second series is sometimes produced. The first have been called nuclei, and those within them nucleoli. Marvellous powers have been attributed to nuclei and nucleoli, and by many these are supposed to be the agents alone con- cerned in the process of multiplication and reproduction. Nuclei and nucleoli are always more intensely coloured by alkaline colouring matters than other parts of the living or germinal matter, a fact which is alone sufficient to show the difference between a true nucleus or new centre, and an oil globule, which has often been wrongly termed a nucleolus. I have endeavoured to show that the bodies called nuclei and nucleoli may be regarded as new centres which have arisen in already existing germinal matter. These new centres may be few or very numerous, and there may be many successive series of such centres, each, when it comes to be developed, manifesting powers different from the pre-existing series. And in certain cases it would appear that as this process of formation of new centres, one within the other, proceeds, new powers are acquired, or if we suppose that all possessed the same powers, those masses only which were last produced retain them, and manifest them when placed under favourable conditions. Although nuclei and nu- cleoli are germinal or living matter, they are not undergoing conversion into formed material. Under certain conditions the nucleus may increase, and exhibit all the phenomena of ordinary germinal matter new nuclei may be developed within it, new nucleoli within them ; so that ordinary ger- minal matter may become formed material, its nucleus growing larger and taking its place. The original nucleolus PLATE 111. OVA Ob' THE COMMON STICKLEBACK. PRODUCTION OL 1 ' NEW LIVING CENTRES IN PRE-EXISTING LIVING MATTER. varian ova undergoing . 11. n:il spots, centres within them, x 1 Germinal spots, with new centres (micleoh) witljin them, and more mmut.- -_V ruiinal soots in the interval." between th<;m. X 500." ICOOth of an i 215. NEW LIVING CENTRES. 47 now becomes the nucleus, and new nucleoli make their appearance in what was the original nucleolus. The whole process consists of evolution from centres, and the produc- tion of new centres within pre-existing centres. Zones of colour, of different intensity, are often observed in a cell coloured with carmine ; the outermost or oldest, or that part which is losing its vital powers, and becoming converted into formed material, being very slightly coloured, the most central part, or the nucleus, although furthest from the colouring solution, exhibiting the greatest intensity of colour. These points are illustrated in PI. VI, fig. 19, and some other figures. Germinal matter, in a comparatively quiescent state is not unfrequently entirely destitute of nuclei, but these bodies sometimes make their appearance if the mass be more freely supplied with nutrient matter. This fact may be noticed in the case of the connective tissue corpuscles, and the masses of germinal matter connected with the walls of vessels, nerves, muscular tissue, epithelium, &c., which often exhibit no nuclei (or according to some, nucleoli), but soon after these tissues become supplied with an increased quantity of pabulum, several small nuclei make their appear- ance in all parts of the germinal matter. (PI. VIII, fig. 36.) So far from nuclei being formed first and the other elements of the cell deposited around them, they make their appearance in the substance of a pre-existing mass of germinal matter, as has been already stated. The true nucleus and nucleolus are not composed of special con- stituents differing from the germinal matter, nor do they perform any special operations. Small oil-globules, which 4 8 PROTOPLASM. invariably result from post-mortem changes in any germinal matter, have often been mistaken for nuclei and nucleoli, but these terms if employed at all should be restricted to the minute masses of germinal matter referred to. THE CELL, OR ELEMENTARY PART. The living matter, with the formed matter upon its surface, whatever may be the structure, properties, and consistence of the latter, is the anatomical unit, the elementary part or cell. This may form the entire organism, in which case, it must be regarded as a complete individual. Millions of such elementary parts or cells are combined to form every tissue and organ of man and the higher animals. However much organisms and tissues in their fully formed state may vary as regards the character, properties, and com- position of the formed material, all were first in the condi- tion of clear, transparent, structureless, formless living matter. Every growing cell, and every cell capable of growth, contains germinal matter. The young cell seems to consist almost entirely of this living material a fact well observed in a specimen of cuticle from the young frog, which may be contrasted with more advanced cuticle from the same animal. In the mature cells only a small mass of germinal matter (usually termed the nucleus) remains. In the fully formed fat cell there is so little germinal matter left, that it may be easily be overlooked. In disease, on the other hand, the germinal matter may increase to three or four times its ordinary amount, when it becomes a very striking object. The ovum at an early period of its PLATE IV. EPITHELIAL CELLS JROM MOUTH. GERMINAL OR LIVING MATTER, RED; .FORMED MATERIAL, BLACK. SHOWING CHANGES DURING GROWTH. h rough thick layer of epithelium covering the papillae of the tongue. sho\viu^ the germ i te formed material ot each elementary unit or e^ll In the lower part of tb ' Inch ara closest to the nutrient matter are seen. Here there are no trepARATF CKIT.S, but the soft formed material forma a continuous mass. 'C'hese ;t: c-!ls, ;ind are irmltipl \ in '; in number When the formed material i '-mid the urm:n;i'. ! : 1:1011 ceaHes. As the cells :IM the surface, c, to take the pla moved, the formed material becomes firna aud dry, and the remains of the germinal matter die. Magnified 700 diameters. of an me!; THE CELL, OR ELEMENTARY PART. 49 development is but a naked mass of germinal matter, with- out a cell wall, but having a new centre and often numerous new centres (known as germinal spots or nuclei) embedded in it, enclosed in a capsule of formed material " cell wall."* The mode of formation of the cell, or elemental unit, as well as the origin from it of other units, is well illustrated in the formation of the ovum. In PI. Ill, fig 7, the cells constituting the tissue of the ovary of the common stickle- back are represented, and amongst them are seen true ova at a very early period of development. The youngest of these differs but little from the cells amongst which it lies. It is, in fact, but one of these which has advanced in de- velopment beyond the rest. In fig. 8, a small but complete ovum is seen with its germinal, or living matter, here called germinal vesicle, surrounded by the yolk which consists of formed matter. In the^ germinal matter are seen numerous germinal spots, which are new living centres of growth originating in living matter. In these are new centres, figs. 9, 10, n, and in these last others would have appeared at a later period. In all cases the lifeless nutrient material must pass into the very centre of the living particles, before the peculiar vital properties are communicated to it. On the Production of Formed Material. The processes of growth and increase, as they occur in the tissues of all * The cell wall (Huxley's "periplastic substance," regarded by him as active and formative) is perfectly passive, while the germinal matter (Huxley's endoplast of 1853, considered by him as unimportant) is the really active and the only living matter of the cell. It is very strange that Mr. Huxley should have so completely modified his views upon this fundamental question, as he has done, without having offered one word in explanation. 50 PROTOPLASM. fully-formed living beings, may be well studied in the simple tissue which forms the external covering of the body, and is prolonged in a modified form into the internal cavities. If a thin section be made perpendicularly through this, down to the tissue which contains the nerves and blood- vessels upon which it rests, the appearances represented in PI. IV, fig. 12, will be observed. In the first place, it will be remarked that in equal bulks of the tissue there is a larger quantity of germinal matter in the lower part, a, which is close to the vessels, than in the upper part, <:, which is a long distance from the nutrient surface, and that the converse is the case as regards the formed material which gives to this tissue its properties and physical -characters, Secondly, it will be noticed that the individual masses of germinal matter increase in size till they arrive at about half way towards the surface, fr, while from this point to the surface they diminish, c; and thirdly, that the distance between them increases on account of the increased formation and accumulation of formed material. By the time the cells have reached the surface, the distance between the masses of germinal matter is reduced again, by the drying and condensation of the formed material. The changes which each individual cell or anatomical unit passes through may now be considered. At the deep aspect near the nutrient surface are masses of germinal matter embedded in a soft, mucus-like, and, as yet, continuous formed material, a. The masses of germinal matter divide, and each of the resulting masses becomes invested with a thin layer of the mucus-like matter. In this way, the elementary parts or cells multiply in number, to compensate for PLATE V. , , : SHOWING FORMED MATERIAL IN THE V1VELY AND THE MODE OF ITS FORMATION. Fig. 14. layer of the conjunctiva iviiring the front of the eye) of a girl, - outiuuous and not yet sept. corresponding to each mass of germinal there are no sej arate c-lla. X i'OO. Superficial or older cells, from the same specimen as Fig. 13, showing formed material belonging to each mass of germinal matter, giving rise to the appearance of separate cells. X 500. 'i-^v- jv. mum) of a young newt, showing masses of germinal matter some of which are dividing, at a, b, c : with form . hich is continuous throughout as in young ..-pilhclmm. Figs. 13, at ,/, Fig. U*. p ol FORMED MA TERIAL. 5 1 the loss of those old cells which are gradually removed from the surface.* Each mass of germinal matter increases in size by the absorption of nutrient pabulum, which, as in all other cases, passes through the layer of formed ' material. But at the same time, a portion of the germinal matter undergoes conversion into formed material, which accumulates upon the surface within that already formed, and as each new layer is deposited upon the surface of the germinal matter, those layers of formed material already pro- duced are stretched, and with them the last developed are more or less incorporated. (PI. VIII, fig. 28, p. 60.) For a time, the germinal matter increases, while new-formed material is being produced. In other words, both the constituent parts of the entire cell increase in amount up to a certain period of its life. (PI. IV, b.) But as new cells continue to be produced below, those already formed are gradually removed farther and farther from the vascular surface, while at the same time their formed material becomes more condensed and less permeable to nutrient matter. From this point, each entire cell ceases to increase in size, while the germinal matter actually diminishes, because it undergoes conversion into formed material ; at the same time, owing to the increased density of the formed material, and its greater distance from the vessels, little new pabulum is taken up to compensate for this. * The description here given is not strictly accurate, inasmuch as the new masses of germinal matter do not all move in a direction to- wards the surface. Some tend in the opposite direction, towards the subcuticular tissue, but this need not be discussed here, as it would complicate the description without helping in any way to elucidate the question now being considered. 2 52 PROTOPLASM. The germinal matter (nucleus) becomes smaller as the cell advances in age. So that it is possible to judge of the age of a cell, irrespective of its size, by the relative amount of its component substances. In old cells, there is much formed material in proportion to the germinal matter, while young cells seem to be composed almost entirely of the latter substance. In very old cells, the small portion of germinal matter still unconverted into formed material, dies, and the cell having by this time arrived at the surface, is cast off, a mass of perfectly passive, lifeless, formed material. The facts here described are illustrated in the figure repre- sented in PL IV, p. 48, which should be carefully studied. Of the so-called Intercellular Substance. In cartilage and some other tissues, there is no line of separation between the portion of formed material which belongs to each mass of germinal matter, as is the case in epi- thelium, but the formed material throughout the entire tissue forms an uninterrupted mass of tissue, matrix, or, as it has been termed, connective substance. (PI. V, fig. 15). From the apparent essential difference in structure, it has been supposed that tissues of this character were developed upon a principle very different to that upon which epithelial structures were produced. It has been maintained by some that in cartilage a cell wall, distinct from the intervening transparent material, existed around each cell, and it has been very generally concluded that the matrix was depo- sited between the cells, and hence this was called " inter- cellular substance." But it must not be supposed that epithelium is in all cases to be distinguished from cartilage by the existence of separate cells. In many forms of epi- PLATE VI. CARTILAGE SHOWING MODE OF PRODUCTION OF FORMED MATERIAL. I-ig. 16. _ Flg , Yl. ocyfiEj Cartilage., frog ; showing germinal i formed material, x 700. :::::::: .;; liiLliiilir .:: ,:;;; \-\^..^-.~~ :: i^susiia ig rartilage, kitten, showing tlie CON- Fig. 19. '<-: at different :\ ' 9. At\ ".attirth; 6. six weeks old ; c, nearly full grown ; d, adult cat. x 'J15. Showing alteration in the lelative proportions of germinal matter and formed material at different ages .' '-i-ninal m; ilage inti page 6-2 INTERCELLULAR SUBSTANCE. 53 thelium at an early period of formation, the formed material corresponding to the several masses of germinal matter is continuous throughout, and presents no indications of divi- sion into separate cells. This is well seen in the lower part of the specimen represented in PI. IV, but in fig. 13, PI. V, an unusually striking example is given. The spe- cimen was taken from the deeper portion of the con- junctival epithelium of man. Not only is there no indi- cation of division into distinct cells, but the structure would be described as a matrix exhibiting spaces occu- pied by the masses of germinal matter. The arrange- ment exactly corresponds with that existing in the case of cartilage, and the masses of germinal matter with a thin investment of formed material may be removed just as in that tissue. It is, therefore, clearly erroneous to consider cartilage and epithelium as representatives of different classes of tissues. The analogy between them will be at once under- stood by a glance at fig. 13, and fig. 15, which have been carefully copied from actual specimens. In fig. 14, a portion of older epithelium from the same surface is represented. In this, each mass of germinal matter is invested with its own layers of formed material, and these are distinct from neighbouring portions. A " cell," or elementary part of fully-formed cartilage and tendon, consists of a mass of germinal matter, with a proportion of formed material around it. A line passing midway between the several masses of germinal matter would mark roughly the limit of the formed material, corresponding to each particular mass of germinal matter, and this would correspond with the outer part of the surface or boundary of the epithelial cell. 54 PROTOPLASM. In order to understand the true relation of the so-called intercellular substance of cartilage or tendon to the masses of germinal matter, it is necessary to study the tissue at different ages. At an early period of development, these tissues appear to consist of masses of germinal matter only. As development advances, the formed material increases, and the masses of germinal matter become separated farther and farther from one another. (PI. VI, fig. 16.) The appear- ances of a cell wall around the germinal matter in the fully-formed tissue, and other alterations which occur, and anomalous appearances which often result as age advances, can be even more readily understood upon the view here advanced, than upon the intercellular-substance theory which has been so strongly supported by some observers. See PI. VI, figs. T 6 to 22. Of the Formation of the Contractile Tissue of Muscle. A muscle "cell," or elementary part, will consist, like that of cartilage and tendon, of the so-called nucleus, with a portion of the muscular tissue corresponding to it. In general arrangement it closely resembles what is seen in tendon. The contractile material of muscle may be shown to be continuous with the germinal matter, and oftentimes a thin filament of the transversely striated tissue may be detached with the oval mass of germinal matter still con- nected with it, showing that, as in tendon, the germinal matter passes uninterruptedly into the formed material. This contractile tissue is not, like the germinal matter which produced it, in a living state. In the formation of the contractile tissue, the germinal matter seems to move onwards, and at its posterior part gradually under- WHAT IS A CELL? 55 goes conversion into the tissue. At the same time it absorbs nutrient material, and thus, although a vast amount of contractile tissue may have been produced, the germinal matter which formed it may not have altered in bulk. (PI. VII, fig. 25.) The fibres of yellow elastic tissue are formed in the same manner, and each fibre is thickened by the formation of new material from germinal matter, which lies upon the external surface of each fibre (fig. 26.). The Formation of Nerve Fibres. The nerve fibre is composed of formed material, which is structurally con- tinuous with the formed material of the nerve cells of the nerve centres. A nerve fibre at an early period of develop- ment consists of a number of oval masses of germinal matter linearly arranged. As development proceeds, these become separated farther and farther from one another, and the non-living tissue which is thus spun off as they become separated, is the nerve. (PI. VII, fig. 27.) What is essential to the Cell? All that is essential to the cell or elementary part is matter that is in the living state germinal matter, and matter that has been in the living state formed material. With these is usually associated a certain proportion of matter about to become living the pabulum or food. So that we may say that in every living thing we have matter in three different states matter about to become living, matter actually living, and matter that has lived. The last, like the first, is non-living, but unlike this it has been in the living state, and has had impressed upon it certain characters which it could not have acquired in any other way. By these characters we know that it has lived, for we can no more 5 6 PROTOPLASM. cause matter artificially to exhibit the characters of the dried leaf, the lifeless wood, shell, bone, hair, or other tissue, than we can make living matter itself in our laboratories. Cells are not like B 'ricks in a Wall. Cells forming a tissue have been compared with bricks in a wall, but the cells are not like bricks, they have not the same con- stitution in every part, nor are they made first and then embedded in the mortar. Each brick of the natural wall grows of itself, places itself in position, forms and embeds itself in the mortar of its own making. The whole wall grows in every part, and while growing may throw out bastions which grow and adapt themselves perfectly to the altering structure. Even now it is argued by some that because things, like fully formed cells, may be made artificially, the actual cells are formed in the same sort of way an argument as forcible as would be that of a person, who after a visit to Madame Tussaud's Exhibition, seriously maintained that our textures were constructed upon the same plan as the " life-like " wax figures he had seen there. Every one who really studies the elementary parts of tissues and investigates the changes which occur as the germinal matter passes through various stages of change until the fully developed structure results, will be careful not to accept without due consideration the vague generali- sations of those who persist in authoritatively declaring that the changes occurring in cell growth are merely mechanical and chemical, although they are unable to produce by any means at their disposal a particle of fibrine, a piece of carti- lage, or even a fragment of coral. They avoid the difficulty PL A'! NUTRITION AND MOVEMENTS OF G5.RMJNAL MATTER. 6 supposed, pabulum, fl i !>v the arrow* iterial and passing into the gr- eat formed rna: c*, oldest portion ot a. terminal matter: ping in the direction iversing the formed. linaL matte it produced ; A minute particle of germinal matter its component spherules of living ma thin layer of so.'t formed, material on undergoing change. tier and Fig. 25. nal matter and formed material (contractile tissue) of muscle. The iermhial m .: 111 the direction Of the arrow. Ir, ' = "~ v^t^,-, .. arwl /, V,ur. ITMH rnov f >