On protoplasm; being an examination of Dr. James Hutchinson Stirling's criticism of Professor Huxley's views

Chapter I

DR. Stirling’s defence of the logical category

OF DIFFERENCE.

The first week of November of 18G8 is a memorable one in tbe annals of pbilosophy in tbe city of Edinburgh. In that week the Archbishop of York delivered the introductory address of the winter session to the members of the Philosophical Institution. In this address his Grace attacked, as from his standpoint he might have been expected to do, the modern experimental school of philosophy, and traced its origin to Comte. It was not to be expected that the champions of 'what the Archbishop styled the “ New Philosophy ’’ would long remain silent. Professor Huxley had previously promised to deliver an evening address on the following Sunday in Edinburgh upon some non-theological subject ; and his studies led him, as a matter of course, to choose some biological topic. But, as all inquiries into the nature of life unavoidably bring us face to face with the most perplexing philosophical problems, it was not strange that Professor Huxley took this opportunity to vindicate the

ON PEOTOPLASM.

New Philosophy from the Archbisliop^s strictures. The title of this lecture^ Protoplasm, or the Physical Basis of Life/^ was in itself sufficiently suggestive ; and after giving a plain statement of the interesting scientific questions involved in his subject, ho proceeded to give his own solution of the philosophical problems which underlie all our knowledge; such as, the nature of matter, mind, causality, force, necessity, and law. He also took exception to the historical truth of the Archbishop in tracing the origin of the New Philosophy ’’ to Comte, and showed that its fundamental conceptions could be proved to have originated with Hume. So far we are dealing with historical facts, and have no wish to arbiti’ate between these two champions of rival schools of philosophical thought.

But soon after another opponent of the ^^New Philosophy appeared on the scene. At a conversazione of the Eoyal College of Physicians of Edinburgh on the evening of the oOth April, 1869, Hr. James Hutchinson Stirling read a paper entitled

As Kegards Protoplasm,^^ in which be commented in very severe terms upon Professor Huxley^s lecture.

This paper was published about six months afterwards as a pamphlet. Interested as we were in the subject, we soon obtained this pamphlet, expecting to find the battle of the philosophies continued ; but to our disappointment, instead of finding a truly philosophical discussion, we either detected, or wo supposed we detected, fundamental misconceptions and misrepresentations of Professor

ON PROTOPLASM.

Huxley^s scientific opinions. Professor Huxley did not make a direct reply to tins attack, but in an essay “ On Yeast/’ which appeat’ed in the December number of the Gontemyorary Bevieiv for 1871, he strengthened his formerposition by a short historical resume of the development of our ideas regarding protoplasm ; and in a few words at the close he charged Dr. Stirling with misrepresenting his views. We quote this passage at length, because it gives us a bird’s-eye view of the whole controversy; and because it was this passage which occasioned the issue of a second edition of Dr. Stirling’s pamphlet. It therefore forms a fitting introduction to its examination.

Dr. Stirling,” says Professor Huxley, winds up his paper with the following paragraph : — ' In short, the whole position of Mr. Huxley, (1) that all organisms consist alike of the same life-matter, (2) which life-matter is, for its part, due only to chemistry, must be pronounced untenable, — nor less untenable (3) the materialism he would found on it.’

^^The paragraph contains three distinct assertions concerning my views, and just the same number of utter misrepresentations of them. That which I have numbered (1) turns on the ambiguity of the word ‘ same,’ for a discussion of which I would refer Dr. Stirling to a great hero of ^Aufklilrung,’ Archbishop Whately. Statement (2) is, in my judgment absurd ; and certainly I have never said anything resembling it; while as to number (3), one great object of my essay was to show that what is

B 2

ON PROTOPLASM.

called ^ materialism ^ has no sound philosophical basis.

AVe shall now proceed to inquire how far Professor Huxley is justified in asserting that Dr. Stirling has misrepresented his views; and this will lead us into a detailed examination of the second edition of his pamphlet ; in which we not only find the original statements repeated^ but a vindication of himself offered against Professor Huxley^s charge. The main object which led Dr. Stirling to publish his paper is best stated in his own words. I may now state/^ he says, “ without any more particular reference to the motives, whether general or special, which gave rise to it, that this essay of mine had but one thing to do, — to protest, namely, against the thoughtless extinction of certain essential differences ill a supposed common identify This being the main object of the essay, it is no wonder that the late Professor Ueberweg, who appears to have taken Professor Huxley^s views upon trust from Dr. Stirling, should say that the “ dialectical leading thought of the essay is “ the contention, namely, for the right of the logical Category of Difference, as against that of Identity, one-sidedly accentuated, as it seems, by Huxley.’’ “^My reply to this was,” proceeds Dr. Stirling, that he [Ueberweg] had hit the mark — that I had been simply laughing all through, and holding up to the Category of Identity, the equally authentic Category

t “ As Regards Protoplasm.” By James Hutchinson Stirling. Second edition, p. 1. Longmans, Green, & Co.

ON PROTOPLASM.

of Difference — but that it had talcen a German to find me out.” * We do not envy the mixture of self-complacency and conceit which dictated this reply. The thoughts of Dr. Stirling are so profound that we, “ amusing Britons that we are ” — the offspring of the “ Aufkliirung/’ and steeped in the philosophy of the “ Eevulsion,” cannot detect him even in his laughter ! We must bear our fate as we may ; but as offspring of the Aufklarung ” it is only natural that we should ask how far this laughter is justified. And when we admit that the danger of the extinction of the Category of Difference is a subject sufficiently provocative of laughter, we are then entitled to ask whether this categoiy is in any danger of extinction by Professor Huxley^s essay. What are the particular passages of this essay which prove that he ignores the differences of protoplasm ? “ Consider, says Dr. Stirling, “ one or two of Mr. Huxley’s own phrases ! ‘ There is

such a thing as a physical basis or matter of life’ — or ‘ the physical basis or matter of life.’ There is ^ a single physical basis of life,’ and through its unity ‘ the whole living world is pervaded by a threefold unity’ — ^namely, a unity of power or faculty, a unity of form, and a unity of substantial composition.’

“ With such expressions ringing in our ears — and they occur on every page — which of us, Mr. Huxley or I, shall be said to be the one who rather imshcs identity’? ”t

* Ibid.

t Ibid., p. 8.

c

ON PROTOPLASM.

Now if we take the first of these phrases^ there is such a tiling as a physical basis or matter of life,” it is manifest that Professor Huxley could not employ such language without believing that there is a certain material element common to all living things; and it is further manifest that he regards this common element as protoplasm, since he uses this term and “ the physical basis of life ” as equivalents. Is Professor Huxley warranted in asserting that there is a certain matter common to everything that lives ? Dr. Stirling thinks that he is not, and adopts two lines of argument to prove the erroneousness of the conclusion. He first affirms that this conclusion is not accepted by the most innovating of the Germans, and secondly he advances a theory of his own which places the nucleus above the protoplasm in importance.

Before proceeding to estimate the value of Dr. Stirling’s arguments under these heads, let us digress for a moment in order to notice the historical development of our present ideas regarding protoplasm. The historical facts, however, are of little use for our present purjDose, except in so far as a survey of them will enable us to seize upon the mental operations concerned in interpreting them. We shall therefore start with the discoveiy of the cell by Schleideii and Schwann, and shall purposely avoid the mention of any other authorities, lest our main object be missed amongst a multiplicity of facts and statements. The typical cell at the time of its discovery was supposed to be a small sac consisting of an external membrane, with contents

ON PEOTOPLASM.

7'

of albuminoid, character^ afterwards called protoplasm, and a small central body of harder consistence called a nucleus. Further observation, however, showed that one or more of these elements might be absent, and the question arose, which of them is to be regarded as the fundamental, never-failing constituent of the morphological unit ? Observation showed that a great many of the bodies called cells really possessed no distinct limiting membrane. The membrane, therefore, was found to bo a special constituent, and could not be regarded as fundamental, hence the moi-phological unit was reduced to a bit of nucleated protoplasm. Can this unit be further simplified ? Professor Huxley says it can. “ But at the very bottom of the animal scale,^^ he remarks, ‘^even this simplicity becomes simplified, and all the phenomena of life are manifested by a particle of protoplasm without a nucleus.^'’* Observation, therefore, shows that life may be present when there is no nucleus and no membrane ; but no observation has ever shown, or is ever likely to show, that any matter is living in the absence of protoplasm. Protoplasm, therefore, is proved by a genuine induction to be the most fundamental and essential material of living organisms, and both the nucleus and the cell-membrane must be regarded as special modifications of the fundamental substance. The conclusion thus reached by the morphologist has been independently attained by the'

* “ Lay Sermons, Addresses, and Eeviews,” by T. H. Huxley, LL.D.,F.R.S., p. 140.

physiologist ; and although the observations of the latter were directed to function and not to structure, yet the method adopted by both was essentially the same, and need not be further particularized here. We are now in a better position to estimate the value of the arguments which Dr. Stirling directs against this inference. As already remarked he attacks it indirectly; (1) by the supposed aid of the German histologists, and (2) by a theory of his own advanced in opposition to it.

In reference to the German histologists he says : — Whatever may be the opinion of the adherents of the molecular theory of generation (namely, that physical molecules combine of themselves into living organisms), it is certain that all the great German histologists still hold by the cell, and can hardly open their mouths without mention of it.^'*

But on the sup])osition that this statement is in great measure true, it is quite irrelevant to the point at issue. The question is, not whether histologists speak frequently of the cell, and still hold by it, but whether they regard the protoplasm as more fundamental and essential than either the nucleus or membrane. Several reasons mio^ht be eriven why not only German histologists, but histologists of all countries, should speak of the cell. But the frequency with which it is spoken of is no measure whatever of the relative importance attached to each of its three constituent elements. No one denies that by far the largest part of plants and

ON PROTOrLASM.

animals are composed of cells and their modifications; hence histologists must necessarily speak more frequently of cells than of any other component; but the frequency with which the cell is mentioned affords no aid in determining the real question at issue, which is, the relative importance of the constituent parts of the cell. Another reason for the frequency with which the cell is mentioned by histologists is, that it was discovered and its significance recognized long before the question of the relative importance of its constituent parts had assumed such consequence. Therefore the whole of descriptive histology started from the cell, which was supposed to be common to all organisms and to all parts of organisms. There can at least be no doubt that the progress of discovery in this case was from the complex cell to the simple protoplasm ; whereas the course of nature is from the simple to the complex. Hence it is that we frequently find histologists speak of a cell, even when both nucleus and membrane are absent. It is perfectly certain, therefore, that no argument can be founded upon the frequency with which the cell is mentioned by histologists, as against the importance which Professor Huxle}'’ attaches to protoplasm.

But it is not true that all German histologists regard the cell as the fundamental morphological unit. In order to avoid the difficulties which the use of the term cell involves, Haeckel, for instance, proposes to call the morphological individuals of the first order — Plastides. He divides the Plastides

ON PROTOPLASM.

into two kinds — Cytodie and CellulfB. The CytodjB he subdivides into Gymuocytodee, unnucleated lumps of plasma without membrane or shell ; and Lepocytoda)^ unnucleated lumps of plasma wuth membrane or shell. The Cellulas he subdivides into Gymnocytm, nucleated lumps of plasma without membrane or shell; and Lepocytee, nucleated lumps of plasma with membrane or shell.* It is perfectly evident that in Haeckehs opinion the lump of plasma (plasmaklum23en), or as he afterwards calls it — the ^Drotoplasm — is the most essential part of the whole. It is present in all the divisions and subdivisions of his classification ; and both the nucleus and membrane, when present, are regarded as special modifications of this fundamental substance. Since Professor Huxley’s essay was delivered as a lecture to a popular audience, it would be quite out of place to give such an elaborate classification of protoplasm and of its modifications as that given by Haeckel ; but he euunciates the whole substance of this classification in a single sentence when he says : protoplasm, simple or

nucleated, is the formal basis of all life.”t But the similarity between the views of Professor Haeckel and of Professor Huxley does not stop here, since the former in 1866 used phrases in describing protoplasm almost the exact equivalents of those used ky the latter in 1869. ^^ilccording to the preceding,” says Haeckel, we call all those organic

t “ Lay Sermons, Addresses, and Reviews,” p. 142.

ON protoplasm:.

materials wliicli are the essential and never-failing media of the movement of lifo^ plasma, cell-matter, or, better, formation-matter (Bildungsstoff) ; the active material substrate of life, and which can, therefore, be called, in a certain narrow sense, the matter of life (Lebensstoff), or the living matter.'’^* And that there may be no mistake respecting the substance of which he is speaking, he proceeds to enumerate the names which have been applied to it by diffei’ent authors, protoplasm being the first name mentioned. What now becomes of Dr. Stirling’s insinuation that the most innovating of the Germans would not sanction the terms in which Professor Huxley describes protoplasm? The truth is, that not only is what Professor Huxley says about simple and nucleated protoplasm perfectly in accord with Haeckel’s classification, but the very phrases adopted by the former might be accepted as good translations of those used by the latter; the ^^kernlose und kernhaltige Plasraaklumpen,” “Bildungsstoff,” “materielle substrate des Lebens,” “Lebensstoff,” of Haeckel, being respectively the equivalents of “ simple and nucleated protoplasm,” “the formal basis of life,” “physical basis of life,” and “ matter of life,” of Professor Huxlev.

Let us now turn to Dr, Stirling’s own theorv, to see if it is sufficiently strong to upset a conclusion founded upon a genuine induction. After noticing the great importance which Goodsir, Schleiden, and Schwann attached to the nucleus. Dr. Stirling, in a

ON PROTOPLASM.

I burst of poetry wliich is surely beyond tlie occasion, proceeds to wish success to this view. This universe/^ he says, is not an accidental cavity, in which an accidental dust has been accidentally swept into heaps for the accidental evolution of the majestic spectacle of organic and inorganic life. That majestic spectacle is a spectacle as plainly for the eye of reason as any diagram of mathematics. That majestic spectacle could have been constructed, teas constructed, only in reason, for reason, and by reason. From beyond Orion and the Pleiades, across the green hem of Earth, up to the imperial personality of man, all, the farthest, the deadest, the dustiest, is for fusion in the invisible point of the single Ego — which alone glorifies it. For the subject, and on the model of the subject, all is made. Therefore it is that — though precisely as there are acephalous monsters by way of exception and deformity, there may be also at the very extremity of animated existence cells without a nucleus, I cannot help believing that this nucleus itself, as analogue of the subject, will yet be proved the most important and indispensable part of all the normal cell-elements. Even the phenomena of the impregnated egg seem to me to support this view. In the egg, on impregnation, it seems to me natural (I say it with a smile) that the old sun that ruled it should go down, and that a new sun, stronger in the combination of the new and the old, should ascend into its place.^^* We have quoted

ON PKOTOPLASM.

this passage at length because no single extract from it would enable the reader to conceive how the facts of natural science are regarded by one who has “ eaten the historic 'pdbiilum out of the vessel of Hegel.'’^ * We shall content ourselves with an endeavour to disentangle the scientific argumentj which, as members of the Aufkliirung/^ we ought to be able to understand, from the mass of poetry and metaphysics, which are quite beyond our appi’eciation. The argument is that in reference to the cell the nucleus is a small central body, and therefore the analogue of the Ego in reference to the body. The Ego is an “ invisible point,^^ occupying a central position in the body; as, I presume, the soul of Descartes had in the pineal gland. But the Ego is the most important and indispensable part of man ; hence its analogue, the nucleus, must be regarded as the most important and indispensable part of the cell. Dr. Stirling tells us in another place that Analogy being never identity, is apt to betray. The difference it hides may be essential, that is, while the likeness it shows may be unessential — so far as the conclusion is concerned.'”t Did Dr. Stirling forget this rule when he drew the analogy between the nucleus and the Ego ? Even were the similarity between them closer, were the Ego like the nucleus a small, spherical, central body, insoluble in acetic acid, it is difficult to perceive why such an analogy should

* See “Kecent British Philosophy,” by David Massou, second edition, p. 9.

t “ As Kegards Protoplasm,” p. 39.

ON PROTOPLASM.

override a conclusion based upon an induction of factSj and therefore founded upon identity. Those who are satisfied with this argument in favour of the nucleus do not require to go further; the battle is lost and won, and Dr. Stirling must be proclaimed victor. Those, however, who prefer to rely upon a conclusion drawn from a careful observation and comparison of facts must acknowledge that Professor Huxley is perfectly justified in applying such phrases to protoplasm as “ the physical basis of life,^^ and ^^tho matter of life,’^ and may proceed with us to examine whether the existence of the Category of Difference is endangered by such statements. W e have already seen that Dr. Stirling

entered the list against Professor Huxley mainly in defence of this category ; it is manifest, therefore, that we are approaching the discussion of the most vital part of the whole controversy.

Wherein consists the identity for which Professor Huxley contends ? This identity is asserted when he says, that, ^‘’notwithstanding apparent difficulties, a threefold unity — namely, a unity of power or faculty, a unity of form, and a unity of substantial composition — does pervade the whole living world. Let us now carefully follow him in tracing the different elements of which this unity, or, if Dr. Stirling prefers it, this identity, consists. Professor Huxley shows in the first place that “ the powers or faculties of all kinds of living matter, diverse as they may be in degree, are substan-

ON PROTOPLASM.

tially similar in kind/^ * The complicated activities of the higher animals — even mental manifestations in their objective aspect — may be comprised under three categories, — those which maintain the individual, those which maintain the species, and those which effect transitory changes in the relative position of parts of the body. But these modes of activity are not exclusively confined to the higher animals ; but are common to every being that lives ; from man and the oak, on the one hand, down to the protamoeba of Haeckel, which merely consists of a speck of undifferentiated protoplasm, on the other. This, then, constitutes the first unity. The second unity is, in Professor Huxley^s own language, that protoplasm, simple or nucleated, is the formal basis of all life.^'’ t ffhe third and last unity is,

■ ‘ that all the forms of protoplasm which have yet been examined contain the four elements, carbon, hydrogen, oxygen, and nitrogen, in very complex union, and that they behave similarly towards several reagents.'’^ | Such, then, is the threefold unity which, according to Professor Huxley, pervades the living world. What are Dr. Stirling's objections to these unities ? and how do they threaten the extinction of the Category of Difference ?

And first with regard to the unity of chemical composition. In this reference. Dr. Stirling says : — “ By substance, Mr. Huxley understands the internal or chemical composition ; and with a mere

IG

ON PEOTOPLASM.

reference to the action of reagents, he asserts the protoplasm of all living beings to be an identical combination of carbon, hydrogen, oxygen, and nitrogen. It is for us to ask, then, are all samples of protoplasm identical, first, in their chemical composition, and, second, under the action of the various reagents ? The reader has only to bring the passage already quoted, in which Professor Huxley declares the unity of composition of protoplasm, into juxtaposition with this quotation, to see how grossly he is misrepresented. His assertion “ that all the forms of protoplasm which have yet been examined contain the four elements, carbon, hydrogen, ox3'^gen, and nitrogen,’^ is converted by Hr. Stirling into the proposition that the protoplasm of living beings is an identical combination of these elements ; and his assertion that all the forms of protoplasm “ behave similarly towards several reagents,’^ into the proposition that their behaviour is “ identical under the action of the various reagents.’^ Having first misrepresented his opponent’s views upon this point. Dr. Stirling has, of course, no difliculty in demolishing them. He can easily show that all the forms of protoplasm are not identical in composition nor in chemical constitution; and that they do not behave in an identical manner under the action of ^^the various reagents ” which he enumerates ; amongst which reagents not one of those which Professor Huxley would include in his '^several reagents” is admitted.

* “As Kcgards Protoplasm,” p. 28.

ON PROTOPLASM.

The whole of the argumentation upon this point is directed against an irrelevant issue. The commonplaces of vital chemistry, which no sane biologist would ever think of denying, are elaborately proved, and positions defended which were never assailed. Even Dr. Stirling himself ultimately obtains a glimpse of this truth. At the close of this part of the argument he says : “ In such a state of the case we cannot wonder that Mr. Huxley^s own conclusion here is : therefore ' all living matter is more or less albuminoid.-’ All living matter is more or less albuminoid ! That, indeed, is the single conclusion of Mr. Huxley^s whole industry ; but it is a conclusion that, far from requiring the intervention of protoplasm, had been reached long before the word itself had been, in this connection, used.^^ * This is, indeed, the main conclusion which Professor Huxley affirmed with regard to the chemical composition of protoplasm ; and if Dr. Stirling accepts it as true, why all this elaborate argument to show that the different kinds of protoplasm are not identical in chemical composition ? If the different kinds of protoplasm are more or less albuminoid, then they have so much identity ; and the only further chemical identity which Professor Huxley affirmed of protoplasm was that which related to its behaviour under the action of several reagents. This conclusion may be very trifling; but, if so, why waste so much time and space in combating it ? We would also remark that Professor Huxley never

ON PKOrOPLASil.

endeavoured to prove the albuminoid nature of living matter through the intervention of protoplasm. Indeed, he never attempted to ijrove its chemical composition at all. He accepted that as a conclusion from the chemists, and applied it to the special aim he had in view. That this conclusion was reached before the word protoplasm had been used in this connection, is no reason whv Professor Huxley should not utilize it for this or for any other purpose. Surely the Category of Difference has nothing to fear from the inference that every kind of protoplasm is at one with every other kind, in so far as that all kinds are aJhumino-id, and that all behave similarly towards several reagents; such as alcohol, for instance, which checks its movements. Such a unity, however, is perfectly consonant with an indefinite amount of variety and difference in other respects.

What has Dr. Stirling to urge against Professor Huxley^s unity of form ? What now,^^ he asks, “ of the unities of form and power in protoplasm ? By form, Mr. Huxley will be found to mean the general appearance and structure; and by faculty or power, the action exhibited. Now it will be very easy to prove that, in neither respect, do all specimens of protoplasm agree. * By agreement it is evident that Dr. Stirling means complete congruity; since the only proof of non-agreement which he offers is an enumeration of various particulars, in which certain kinds of protoplasm dif-

01^ PROTOPLASM.

fer from each other. But would any sane man, not to speak of a distinguished biologist like Professor Huxley, maintain that there is a complete agreement in general appearance and structure between all the kinds of protoplasm ? W ere such a statement made, it would requii’e no involved, reasoning for its refutation. The perceptions received from the direct observation of tissues, like nerve and muscle, would suffice for this purpose. Yet we find Dr. Stirling putting himself to the trouble of quoting Strieker to show that we have club-shaped protoplasm, globe-shaped protoplasm, cup-shaped protoplasm, &c. * It never occurs to him to

inquire whether Professor Huxley^s language involves such an insane idea as he attributes to him. Professor Huxley^s language does not of course bear such an interpretation, nor can we imagine how any one could so construe it. Dr. Stirling will himself admit that, for the vast majority of living beings and tissues the cell is the structural unit. But, as already pointed out, the cell is a complex body, and the question arose, which of its three constituent parts is the essential or fundamental one. At present biologists decide in favour of the protoplasm, and Professor Huxley^s statement simply amounts to the old conclusion, that the cell is the structural unit ; the mode of expression being modified in such a manner as to adapt this conclusion to the recent change in the theory of the cell. Instead of saying the cell, he says.

* Ibid.

c 2

ON PROTOPLASM.

^'protoplasm, simple or nucleated, is the formal basis of life,^^ or structural unit ; and such being the case, every form of living thing is so much at one with every other living thing ; while it is possible for them to possess every other imaginable structural variety and difference : Dr. Stirling may think this conclusion a very trifling one, and one that was known in every sense but a vei’bal one before the word protoplasm was invented ; but whatever may bo his opinion upon this point, it is perfectly certain that the Category of Difference was never denied, and has nothing to fear from the inference.

Dr. Stirling's objections to Px’ofessor Huxley unity of power or faculty remain now to be considered. As already noticed. Professor Huxley asserts that all the activities of living beings may be comprised under three categories, namely, alimentation, reproduction, and contractility ; and in these consists the unity of living beings as regards faculty. Dr. Stirling himself admits that all living beings, from the lowest to the highest, do feed and reproduce themselves. Nay ! he has asserted much more than this with regard to reproduction. He says that, " from the very earliest moment — even literally ah ouo — brain-cells only generate brain-cells, bone-cells bone-cells, and so on.^^ *