Let us now note the courses forced upon biologists by the difficulties of Mr. Darwin's distinctive feature. Mr. Darwin and Mr. Wallace, as is well known, brought the feature forward simultaneously and independently of one another, but Mr. Wallace always believed in it more firmly than Mr. Darwin did. Mr. Darwin as a young man did not believe in it. He wrote before 1889, "Nature, by making habit omnipotent and its effects hereditary, has fitted the Fuegian for the climate and productions of his country," {21} a sentence than which nothing can coincide more fully with the older view that use and disuse were the main purveyors of variations, or conflict more fatally with his own subsequent distinctive feature. Moreover, as I showed in my last work on evolution, {22} in the peroration to his "Origin of Species," he discarded his accidental variations altogether, and fell back on the older theory, so that the body of the "Origin of Species" supports one theory, and the peroration another that differs from it toto coelo. Finally, in his later editions, he retreated indefinitely from his original position, edging always more and more continually towards the theory of his grandfather and Lamarck. These facts convince me that he was at no time a thorough- going Darwinian, but was throughout an unconscious Lamarckian, though ever anxious to conceal the fact alike from himself and from his readers.

Not so with Mr. Wallace, who was both more outspoken in the first instance, and who has persevered along the path of Wallaceism just as Mr. Darwin with greater sagacity was ever on the retreat from Darwinism. Mr. Wallace's profounder faith led him in the outset to place his theory in fuller daylight than Mr. Darwin was inclined to do. Mr. Darwin just waved Lamarck aside, and said as little about him as he could, while in his earlier editions Erasmus Darwin and Buffon were not so much as named. Mr. Wallace, on the contrary, at once raised the Lamarckian spectre, and declared it exorcised. He said the Lamarckian hypothesis was "quite unnecessary." The giraffe did not "acquire its long neck by desiring to reach the foliage of the more lofty shrubs, and constantly stretching its neck for this purpose, but because any varieties which occurred among its antitypes with a longer neck than usual at once secured a fresh range of pasture over the same ground as their shorter-necked companions, and on the first scarcity of food were thus enabled to outlive them." {23}

"Which occurred" is evidently "which happened to occur" by some chance or accident unconnected with use and disuse. The word "accident" is never used, but Mr. Wallace must be credited with this instance of a desire to give his readers a chance of perceiving that according to his distinctive feature evolution is an affair of luck, rather than of cunning. Whether his readers actually did understand this as clearly as Mr. Wallace doubtless desired that they should, and whether greater development at this point would not have helped them to fuller apprehension, we need not now inquire. What was gained in distinctness might have been lost in distinctiveness, and after all he did technically put us upon our guard.

Nevertheless he too at a pinch takes refuge in Lamarckism. In relation to the manner in which the eyes of soles, turbots, and other flat-fish travel round the head so as to become in the end unsymmetrically placed, he says:—

"The eyes of these fish are curiously distorted in order that both eyes may be upon the upper side, where alone they would be of any use. . . . Now if we suppose this process, which in the young is completed in a few days or weeks, to have been spread over thousands of generations during the development of these fish, those usually surviving whose eyes retained more and more of the position into which the young fish tried to twist them [italics mine], the change becomes intelligible." {24} When it was said by Professor Ray Lankester—who knows as well as most people what Lamarck taught—that this was "flat Lamarckism," Mr. Wallace rejoined that it was the survival of the modified individuals that did it all, not the efforts of the young fish to twist their eyes, and the transmission to descendants of the effects of those efforts. But this, as I said in my book, "Evolution, Old and New," {25} is like saying that horses are swift runners, not by reason of the causes, whatever they were, that occasioned the direct line of their progenitors to vary towards ever greater and greater swiftness, but because their more slow- going uncles and aunts go away. Plain people will prefer to say that the main cause of any accumulation of favourable modifications consists rather in that which brings about the initial variations, and in the fact that these can be inherited at all, than in the fact that the unmodified individuals were not successful. People do not become rich because the poor in large numbers go away, but because they have been lucky, or provident, or more commonly both. If they would keep their wealth when they have made it they must exclude luck thenceforth to the utmost of their power, and their children must follow their example, or they will soon lose their money. The fact that the weaker go to the wall does not bring about the greater strength of the stronger; it is the consequence of this last and not the cause—unless, indeed, it be contended that a knowledge that the weak go to the wall stimulates the strong to exertions which they would not otherwise so make, and that these exertions produce inheritable modifications. Even in this case, however, it would be the exertions, or use and disuse, that would be the main agents in the modification. But it is not often that Mr. Wallace thus backslides. His present position is that acquired (as distinguished from congenital) modifications are not inherited at all. He does not indeed put his faith prominently forward and pin himself to it as plainly as could be wished, but under the heading, "The Non-Heredity of Acquired Characters," he writes as follows on p. 440 of his recent work in reference to Professor Weismann's Theory of Heredity:—

"Certain observations on the embryology of the lower animals are held to afford direct proof of this theory of heredity, but they are too technical to be made clear to ordinary readers. A logical result of the theory is the impossibility of the transmission of acquired characters, since the molecular structure of the germ-plasm is already determined within the embryo; and Weismann holds that there are no facts which really prove that acquired characters can be inherited, although their inheritance has, by most writers, been considered so probable as hardly to stand in need of direct proof.

"We have already seen in the earlier part of this chapter that many instances of change, imputed to the inheritance of acquired variations, are really cases of selection."

And the rest of the remarks tend to convey the impression that Mr. Wallace adopts Professor Weismann's view, but, curiously enough, though I have gone through Mr. Wallace's book with a special view to this particular point, I have not been able to find him definitely committing himself either to the assertion that acquired modifications never are inherited, or that they sometimes are so. It is abundantly laid down that Mr. Darwin laid too much stress on use and disuse, and a residuary impression is left that Mr. Wallace is endorsing Professor Weismann's view, but I have found it impossible to collect anything that enables me to define his position confidently in this respect.

This is natural enough, for Mr. Wallace has entitled his book "Darwinism," and a work denying that use and disuse produced any effect could not conceivably be called Darwinism. Mr. Herbert Spencer has recently collected many passages from "The Origin of Species" and from "Animals and Plants under Domestication," {26} which show how largely, after all, use and disuse entered into Mr. Darwin's system, and we know that in his later years he attached still more importance to them. It was out of the question, therefore, that Mr. Wallace should categorically deny that their effects were inheritable. On the other hand, the temptation to adopt Professor Weismann's view must have been overwhelming to one who had been already inclined to minimise the effects of use and disuse. On the whole, one does not see what Mr. Wallace could do, other than what he has done—unless, of course, he changed his title, or had been no longer Mr. Wallace.

Besides, thanks to the works of Mr. Spencer, Professor Mivart, Professor Semper, and very many others, there has for some time been a growing perception that the Darwinism of Charles Darwin was doomed. Use and disuse must either do even more than is officially recognised in Mr. Darwin's later concessions, or they must do a great deal less. If they can do as much as Mr. Darwin himself said they did, why should they not do more? Why stop where Mr. Darwin did? And again, where in the name of all that is reasonable did he really stop? He drew no line, and on what principle can we say that so much is possible as effect of use and disuse, but so much more impossible? If, as Mr. Darwin contended, disuse can so far reduce an organ as to render it rudimentary, and in many cases get rid of it altogether, why cannot use create as much as disuse can destroy, provided it has anything, no matter how low in structure, to begin with? Let us know where we stand. If it is admitted that use and disuse can do a good deal, what does a good deal mean? And what is the proportion between the shares attributable to use and disuse and to natural selection respectively? If we cannot be told with absolute precision, let us at any rate have something more definite than the statement that natural selection is "the most important means of modification."

Mr. Darwin gave us no help in this respect; and worse than this, he contradicted himself so flatly as to show that he had very little definite idea upon the subject at all. Thus in respect to the winglessness of the Madeira beetles he wrote:—

"In some cases we might easily put down to disuse modifications of structure, which are wholly or mainly due to natural selection. Mr. Wollaston has discovered the remarkable fact that 200 beetles, out of the 550 species (but more are now known) inhabiting Madeira, are so far deficient in wings that they cannot fly; and that of the 29 endemic genera no less than 23 have all their species in this condition! Several facts,—namely, that beetles in many parts of the world are frequently blown out to sea and perish; that the beetles in Madeira, as observed by Mr. Wollaston, lie much concealed until the wind lulls and the sun shines; that the proportion of wingless beetles is larger on the exposed Desertas than in Madeira itself; and especially the extraordinary fact, so strongly insisted on by Mr. Wollaston, that certain large groups of beetles, elsewhere excessively numerous, which absolutely require the use of their wings are here almost entirely absent;—these several considerations make me believe that the wingless condition of so many Madeira beetles is mainly due to the action of natural selection, combined probably with disuse [italics mine]. For during many successive generations each individual beetle which flew least, either from its wings having been ever so little less perfectly developed or from indolent habit, will have had the best chance of surviving, from not being blown out to sea; and, on the other hand, those beetles which most readily took to flight would oftenest have been blown to sea, and thus destroyed." {27}

We should like to know, first, somewhere about how much disuse was able to do after all, and moreover why, if it can do anything at all, it should not be able to do all. Mr. Darwin says: "Any change in structure and function which can be effected by small stages is within the power of natural selection." "And why not," we ask, "within the power of use and disuse?" Moreover, on a later page we find Mr. Darwin saying:—

"It appears probable that disuse has been the main agent in rendering organs rudimentary [italics mine]. It would at first lead by slow steps to the more and more complete reduction of a part, until at last it has become rudimentary—as in the case of the eyes of animals inhabiting dark caverns, and of the wings of birds inhabiting oceanic islands, which have seldom been forced by beasts of prey to take flight, and have ultimately lost the power of flying. Again, an organ, useful under certain conditions, might become injurious under others, as with the wings of beetles living on small and exposed islands; and in this case natural selection will have aided in reducing the organ, until it was rendered harmless and rudimentary [italics mine]." {28}

So that just as an undefined amount of use and disuse was introduced on the earlier page to supplement the effects of natural selection in respect of the wings of beetles on small and exposed islands, we have here an undefined amount of natural selection introduced to supplement the effects of use and disuse in respect of the identical phenomena. In the one passage we find that natural selection has been the main agent in reducing the wings, though use and disuse have had an appreciable share in the result; in the other, it is use and disuse that have been the main agents, though an appreciable share in the result must be ascribed to natural selection.

Besides, who has seen the uncles and aunts going away with the uniformity that is necessary for Mr. Darwin's contention? We know that birds and insects do often get blown out to sea and perish, but in order to establish Mr. Darwin's position we want the evidence of those who watched the reduction of the wings during the many generations in the course of which it was being effected, and who can testify that all, or the overwhelming majority, of the beetles born with fairly well-developed wings got blown out to sea, while those alone survived whose wings were congenitally degenerate. Who saw them go, or can point to analogous cases so conclusive as to compel assent from any equitable thinker?

Darwinians of the stamp of Mr. Thiselton Dyer, Professor Ray Lankester, or Mr. Romanes, insist on their pound of flesh in the matter of irrefragable demonstration. They complain of us for not bringing forward some one who has been able to detect the movement of the hour-hand of a watch during a second of time, and when we fail to do so, declare triumphantly that we have no evidence that there is any connection between the beating of a second and the movement of the hour-hand. When we say that rain comes from the condensation of moisture in the atmosphere, they demand of us a rain-drop from moisture not yet condensed. If they stickle for proof and cavil on the ninth part of a hair, as they do when we bring forward what we deem excellent instances of the transmission of an acquired characteristic, why may not we, too, demand at any rate some evidence that the unmodified beetles actually did always, or nearly always, get blown out to sea, during the reduction above referred to, and that it is to this fact, and not to the masterly inactivity of their fathers and mothers, that the Madeira beetles owe their winglessness? If we began stickling for proof in this way, our opponents would not be long in letting us know that absolute proof is unattainable on any subject, that reasonable presumption is our highest certainty, and that crying out for too much evidence is as bad as accepting too little. Truth is like a photographic sensitised plate, which is equally ruined by over and by under exposure, and the just exposure for which can never be absolutely determined.

Surely if disuse can be credited with the vast powers involved in Mr. Darwin's statement that it has probably "been the main agent in rendering organs rudimentary," no limits are assignable to the accumulated effects of habit, provided the effects of habit, or use and disuse, are supposed, as Mr. Darwin supposed them, to be inheritable at all. Darwinians have at length woke up to the dilemma in which they are placed by the manner in which Mr. Darwin tried to sit on the two stools of use and disuse, and natural selection of accidental variations, at the same time. The knell of Charles-Darwinism is rung in Mr. Wallace's present book, and in the general perception on the part of biologists that we must either assign to use and disuse such a predominant share in modification as to make it the feature most proper to be insisted on, or deny that the modifications, whether of mind or body, acquired during a single lifetime, are ever transmitted at all. If they can be inherited at all, they can be accumulated. If they can be accumulated at all, they can be so, for anything that appears to the contrary, to the extent of the specific and generic differences with which we are surrounded. The only thing to do is to pluck them out root and branch: they are as a cancer which, if the smallest fibre be left unexcised, will grow again, and kill any system on to which it is allowed to fasten. Mr. Wallace, therefore, may well be excused if he casts longing eyes towards Weismannism.

And what was Mr. Darwin's system? Who can make head or tail of the inextricable muddle in which he left it? The "Origin of Species" in its latest shape is the reduction of hedging to an absurdity. How did Mr. Darwin himself leave it in the last chapter of the last edition of the "Origin of Species"? He wrote:—

"I have now recapitulated the facts and considerations which have thoroughly convinced me that species have been modified during a long course of descent. This has been effected chiefly through the natural selection of numerous, successive, slight, favourable variations; aided in an important manner by the inherited effects of the use and disuse of parts, and in an unimportant manner—that is, in relation to adaptive structures whether past or present—by the direct action of external conditions, and by variations which seem to us in our ignorance to arise spontaneously. It appears that I formerly underrated the frequency and value of these latter forms of variation, as leading to permanent modifications of structure independently of natural selection."

The "numerous, successive, slight, favourable variations" above referred to are intended to be fortuitous, accidental, spontaneous. It is the essence of Mr. Darwin's theory that this should be so. Mr. Darwin's solemn statement, therefore, of his theory, after he had done his best or his worst with it, is, when stripped of surplusage, as follows:—

"The modification of species has been mainly effected by accumulation of spontaneous variations; it has been aided in an important manner by accumulation of variations due to use and disuse, and in an unimportant manner by spontaneous variations; I do not even now think that spontaneous variations have been very important, but I used once to think them less important than I do now."

It is a discouraging symptom of the age that such a system should have been so long belauded, and it is a sign of returning intelligence that even he who has been more especially the alter ego of Mr. Darwin should have felt constrained to close the chapter of Charles-Darwinism as a living theory, and relegate it to the important but not very creditable place in history which it must henceforth occupy. It is astonishing, however, that Mr. Wallace should have quoted the extract from the "Origin of Species" just given, as he has done on p. 412 of his "Darwinism," without betraying any sign that he has caught its driftlessness—for drift, other than a desire to hedge, it assuredly has not got. The battle now turns on the question whether modifications of either structure or instinct due to use or disuse are ever inherited, or whether they are not. Can the effects of habit be transmitted to progeny at all? We know that more usually they are not transmitted to any perceptible extent, but we believe also that occasionally, and indeed not infrequently, they are inherited and even intensified. What are our grounds for this opinion? It will be my object to put these forward in the following number of the Universal Review.



THE DEADLOCK IN DARWINISM—PART II {29}

At the close of my article in last month's number of the Universal Review, I said I would in this month's issue show why the opponents of Charles-Darwinism believe the effects of habits acquired during the lifetime of a parent to produce an effect on their subsequent offspring, in spite of the fact that we can rarely find the effect in any one generation, or even in several, sufficiently marked to arrest our attention.

I will now show that offspring can be, and not very infrequently is, affected by occurrences that have produced a deep impression on the parent organism—the effect produced on the offspring being such as leaves no doubt that it is to be connected with the impression produced on the parent. Having thus established the general proposition, I will proceed to the more particular one—that habits, involving use and disuse of special organs, with the modifications of structure thereby engendered, produce also an effect upon offspring, which, though seldom perceptible as regards structure in a single, or even in several generations, is nevertheless capable of being accumulated in successive generations till it amounts to specific and generic difference. I have found the first point as much as I can treat within the limits of this present article, and will avail myself of the hospitality of the Universal Review next month to deal with the second.

The proposition which I have to defend is one which no one till recently would have questioned, and even now, those who look most askance at it do not venture to dispute it unreservedly; they every now and then admit it as conceivable, and even in some cases probable; nevertheless they seek to minimise it, and to make out that there is little or no connection between the great mass of the cells of which the body is composed, and those cells that are alone capable of reproducing the entire organism. The tendency is to assign to these last a life of their own, apart from, and unconnected with that of the other cells of the body, and to cheapen all evidence that tends to prove any response on their part to the past history of the individual, and hence ultimately of the race.

Professor Weismann is the foremost exponent of those who take this line. He has naturally been welcomed by English Charles-Darwinians; for if his view can be sustained, then it can be contended that use and disuse produce no transmissible effect, and the ground is cut from under Lamarck's feet; if, on the other hand, his view is unfounded, the Lamarckian reaction, already strong, will gain still further strength. The issue, therefore, is important, and is being fiercely contested by those who have invested their all of reputation for discernment in Charles-Darwinian securities.

Professor Weismann's theory is, that at every new birth a part of the substance which proceeds from parents and which goes to form the new embryo is not used up in forming the new animal, but remains apart to generate the germ-cells—or perhaps I should say "germ-plasm"—which the new animal itself will in due course issue.

Contrasting the generally received view with his own, Professor Weismann says that according to the first of these "the organism produces germ- cells afresh again and again, and that it produces them entirely from its own substance." While by the second "the germ-cells are no longer looked upon as the product of the parent's body, at least as far as their essential part—the specific germ-plasm—is concerned; they are rather considered as something which is to be placed in contrast with the tout ensemble of the cells which make up the parent's body, and the germ-cells of succeeding generations stand in a similar relation to one another as a series of generations of unicellular organisms arising by a continued process of cell-division." {30}

On another page he writes:—

"I believe that heredity depends upon the fact that a small portion of the effective substance of the germ, the germ-plasm, remains unchanged during the development of the ovum into an organism, and that this part of the germ-plasm serves as a foundation from which the germ-cells of the new organism are produced. There is, therefore, continuity of the germ- plasm from one generation to another. One might represent the germ-plasm by the metaphor of a long creeping root-stock from which plants arise at intervals, these latter representing the individuals of successive generations." {31}

Mr. Wallace, who does not appear to have read Professor Weismann's essays themselves, but whose remarks are, no doubt, ultimately derived from the sequel to the passage just quoted from page 266 of Professor Weismann's book, contends that the impossibility of the transmission of acquired characters follows as a logical result from Professor Weismann's theory, inasmuch as the molecular structure of the germ-plasm that will go to form any succeeding generation is already predetermined within the still unformed embryo of its predecessor; "and Weismann," continues Mr. Wallace, "holds that there are no facts which really prove that acquired characters can be inherited, although their inheritance has, by most writers, been considered so probable as hardly to stand in need of direct proof." {32}

Professor Weismann, in passages too numerous to quote, shows that he recognises this necessity, and acknowledges that the non-transmission of acquired characters "forms the foundation of the views" set forth in his book, p. 291.

Professor Ray Lankester does not commit himself absolutely to this view, but lends it support by saying (Nature, December 12, 1889): "It is hardly necessary to say that it has never yet been shown experimentally that anything acquired by one generation is transmitted to the next (putting aside diseases)."

Mr. Romanes, writing in Nature, March 18, 1890, and opposing certain details of Professor Weismann's theory, so far supports it as to say that "there is the gravest possible doubt lying against the supposition that any really inherited decrease is due to the inherited effects of disuse." The "gravest possible doubt" should mean that Mr. Romanes regards it as a moral certainty that disuse has no transmitted effect in reducing an organ, and it should follow that he holds use to have no transmitted effect in its development. The sequel, however, makes me uncertain how far Mr. Romanes intends this, and I would refer the reader to the article which Mr. Romanes has just published on Weismann in the Contemporary Review for this current month.

The burden of Mr. Thiselton Dyer's controversy with the Duke of Argyll (see Nature, January 16, 1890, et seq.) was that there was no evidence in support of the transmission of any acquired modification. The orthodoxy of science, therefore, must be held as giving at any rate a provisional support to Professor Weismann, but all of them, including even Professor Weismann himself, shrink from committing themselves to the opinion that the germ-cells of any organisms remain in all cases unaffected by the events that occur to the other cells of the same organism, and until they do this they have knocked the bottom out of their case.

From among the passages in which Professor Weismann himself shows a desire to hedge I may take the following from page 170 of his book:—

"I am also far from asserting that the germ-plasm which, as I hold, is transmitted as the basis of heredity from one generation to another, is absolutely unchangeable or totally uninfluenced by forces residing in the organism within which it is transformed into germ-cells. I am also compelled to admit it as conceivable that organisms may exert a modifying influence upon their germ-cells, and even that such a process is to a certain extent inevitable. The nutrition and growth of the individual must exercise some influence upon its germ-cells . . . "

Professor Weismann does indeed go on to say that this influence must be extremely slight, but we do not care how slight the changes produced may be provided they exist and can be transmitted. On an earlier page (p. 101) he said in regard to variations generally that we should not expect to find them conspicuous; their frequency would be enough, if they could be accumulated. The same applies here, if stirring events that occur to the somatic cells can produce any effect at all on offspring. A very small effect, provided it can be repeated and accumulated in successive generations, is all that even the most exacting Lamarckian will ask for.

Having now made the reader acquainted with the position taken by the leading Charles-Darwinian authorities, I will return to Professor Weismann himself, who declares that the transmission of acquired characters "at first sight certainly seems necessary," and that "it appears rash to attempt to dispense with its aid." He continues:—

"Many phenomena only appear to be intelligible if we assume the hereditary transmission of such acquired characters as the changes which we ascribe to the use or disuse of particular organs, or to the direct influence of climate. Furthermore, how can we explain instinct as hereditary habit, unless it has gradually arisen by the accumulation, through heredity, of habits which were practised in succeeding generations?" {33}

I may say in passing that Professor Weismann appears to suppose that the view of instinct just given is part of the Charles-Darwinian system, for on page 889 of his book he says "that many observers had followed Darwin in explaining them [instincts] as inherited habits." This was not Mr. Darwin's own view of the matter. He wrote:—

"If we suppose any habitual action to become inherited—and I think it can be shown that this does sometimes happen—then the resemblance between what originally was a habit and an instinct becomes so close as not to be distinguished. . . But it would be the most serious error to suppose that the greater number of instincts have been acquired by habit in one generation, and then transmitted by inheritance to succeeding generations. It can be clearly shown that the most wonderful instincts with which we are acquainted, namely, those of the hive-bee and of many ants, could not possibly have been thus acquired."—["Origin of Species," ed., 1859, p. 209.]

Again we read: "Domestic instincts are sometimes spoken of as actions which have become inherited solely from long-continued and compulsory habit, but this, I think, is not true."—Ibid., p. 214.

Again: "I am surprised that no one has advanced this demonstrative case of neuter insects, against the well-known doctrine of inherited habit, as advanced by Lamarck."—["Origin of Species," ed. 1872, p. 283.]

I am not aware that Lamarck advanced the doctrine that instinct is inherited habit, but he may have done so in some work that I have not seen.

It is true, as I have more than once pointed out, that in the later editions of the "Origin of Species" it is no longer "the most serious" error to refer instincts generally to inherited habit, but it still remains "a serious error," and this slight relaxation of severity does not warrant Professor Weismann in ascribing to Mr. Darwin an opinion which he emphatically condemned. His tone, however, is so offhand, that those who have little acquaintance with the literature of evolution would hardly guess that he is not much better informed on this subject than themselves.

Returning to the inheritance of acquired characters, Professor Weismann says that this has never been proved either by means of direct observation or by experiment. "It must be admitted," he writes, "that there are in existence numerous descriptions of cases which tend to prove that such mutilations as the loss of fingers, the scars of wounds, &c., are inherited by the offspring, but in these descriptions the previous history is invariably obscure, and hence the evidence loses all scientific value."

The experiments of M. Brown-Sequard throw so much light upon the question at issue that I will quote at some length from the summary given by Mr. Darwin in his "Variation of Animals and Plants under Domestication." {34} Mr. Darwin writes:—

"With respect to the inheritance of structures mutilated by injuries or altered by disease, it was until lately difficult to come to any definite conclusion." [Then follow several cases in which mutilations practised for many generations are not found to be transmitted.] "Notwithstanding," continues Mr. Darwin, "the above several negative cases, we now possess conclusive evidence that the effects of operations are sometimes inherited. Dr. Brown-Sequard gives the following summary of his observations on guinea-pigs, and this summary is so important that I will quote the whole:—

"'1st. Appearance of epilepsy in animals born of parents having been rendered epileptic by an injury to the spinal cord.

"'2nd. Appearance of epilepsy also in animals born of parents having been rendered epileptic by the section of the sciatic nerve.

"'3rd. A change in the shape of the ear in animals born of parents in which such a change was the effect of a division of the cervical sympathetic nerve.

"'4th. Partial closure of the eyelids in animals born of parents in which that state of the eyelids had been caused either by the section of the cervical sympathetic nerve or the removal of the superior cervical ganglion.

"'5th. Exophthalmia in animals born of parents in which an injury to the restiform body had produced that protrusion of the eyeball. This interesting fact I have witnessed a good many times, and I have seen the transmission of the morbid state of the eye continue through four generations. In these animals modified by heredity, the two eyes generally protruded, although in the parents usually only one showed exophthalmia, the lesion having been made in most cases only on one of the corpora restiformia.

"'6th. Haematoma and dry gangrene of the ears in animals born of parents in which these ear-alterations had been caused by an injury to the restiform body near the nib of the calamus.

"'7th. Absence of two toes out of the three of the hind leg, and sometimes of the three, in animals whose parents had eaten up their hind- leg toes which had become anaesthetic from a section of the sciatic nerve alone, or of that nerve and also of the crural. Sometimes, instead of complete absence of the toes, only a part of one or two or three was missing in the young, although in the parent not only the toes but the whole foot was absent (partly eaten off, partly destroyed by inflammation, ulceration, or gangrene).

"'8th. Appearance of various morbid states of the skin and hair of the neck and face in animals born of parents having had similar alterations in the same parts, as effects of an injury to the sciatic nerve.'

"It should be especially observed that Brown-Sequard has bred during thirty years many thousand guinea-pigs from animals which had not been operated upon, and not one of these manifested the epileptic tendency. Nor has he ever seen a guinea-pig born without toes, which was not the offspring of parents which had gnawed off their own toes owing to the sciatic nerve having been divided. Of this latter fact thirteen instances were carefully recorded, and a greater number were seen; yet Brown-Sequard speaks of such cases as one of the rarer forms of inheritance. It is a still more interesting fact, 'that the sciatic nerve in the congenitally toeless animal has inherited the power of passing through all the different morbid states which have occurred in one of its parents from the time of the division till after its reunion with the peripheric end. It is not, therefore, simply the power of performing an action which is inherited, but the power of performing a whole series of actions, in a certain order.'

"In most of the cases of inheritance recorded by Brown-Sequard only one of the two parents had been operated upon and was affected. He concludes by expressing his belief that 'what is transmitted is the morbid state of the nervous system,' due to the operation performed on the parents."

Mr. Darwin proceeds to give other instances of inherited effects of mutilations:—

"With the horse there seems hardly a doubt that exostoses on the legs, caused by too much travelling on hard roads, are inherited. Blumenbach records the case of a man who had his little finger on the right hand almost cut off, and which in consequence grew crooked, and his sons had the same finger on the same hand similarly crooked. A soldier, fifteen years before his marriage, lost his left eye from purulent ophthalmia, and his two sons were microphthalmic on the same side."

The late Professor Rolleston, whose competence as an observer no one is likely to dispute, gave Mr. Darwin two cases as having fallen under his own notice, one of a man whose knee had been severely wounded, and whose child was born with the same spot marked or scarred, and the other of one who was severely cut upon the cheek, and whose child was born scarred in the same place. Mr. Darwin's conclusion was that "the effects of injuries, especially when followed by disease, or perhaps exclusively when thus followed, are occasionally inherited."

Let us now see what Professor Weismann has to say against this. He writes:—

"The only cases worthy of discussion are the well-known experiments upon guinea-pigs conducted by the French physiologist, Brown-Sequard. But the explanation of his results is, in my opinion, open to discussion. In these cases we have to do with the apparent transmission of artificially produced malformations . . . All these effects were said to be transmitted to descendants as far as the fifth or sixth generation.

"But we must inquire whether these cases are really due to heredity, and not to simple infection. In the case of epilepsy, at any rate, it is easy to imagine that the passage of some specific organism through the reproductive cells may take place, as in the case of syphilis. We are, however, entirely ignorant of the nature of the former disease. This suggested explanation may not perhaps apply to the other cases; but we must remember that animals which have been subjected to such severe operations upon the nervous system have sustained a great shock, and if they are capable of breeding, it is only probable that they will produce weak descendants, and such as are easily affected by disease. Such a result does not, however, explain why the offspring should suffer from the same disease as that which was artificially induced in the parents. But this does not appear to have been by any means invariably the case. Brown-Sequard himself says: 'The changes in the eye of the offspring were of a very variable nature, and were only occasionally exactly similar to those observed in the parents.'

"There is no doubt, however, that these experiments demand careful consideration, but before they can claim scientific recognition, they must be subjected to rigid criticism as to the precautions taken, the nature and number of the control experiments, &c.

"Up to the present time such necessary conditions have not been sufficiently observed. The recent experiments themselves are only described in short preliminary notices, which, as regards their accuracy, the possibility of mistake, the precautions taken, and the exact succession of individuals affected, afford no data on which a scientific opinion can be founded" (pp. 81, 82).

The line Professor Weismann takes, therefore, is to discredit the facts; yet on a later page we find that the experiments have since been repeated by Obersteiner, "who has described them in a very exact and unprejudiced manner," and that "the fact"—(I imagine that Professor Weismann intends "the facts")—"cannot be doubted."

On a still later page, however, we read:—

"If, for instance, it could be shown that artificial mutilation spontaneously reappears in the offspring with sufficient frequency to exclude all possibilities of chance, then such proof [i.e., that acquired characters can be transmitted] would be forthcoming. The transmission of mutilations has been frequently asserted, and has been even recently again brought forward, but all the supposed instances have broken down when carefully examined" (p. 390).

Here, then, we are told that proof of the occasional transmission of mutilations would be sufficient to establish the fact, but on p. 267 we find that no single fact is known which really proves that acquired characters can be transmitted, "for the ascertained facts which seem to point to the transmission of artificially produced diseases cannot be considered as proof" [Italics mine.] Perhaps; but it was mutilation in many cases that Professor Weismann practically admitted to have been transmitted when he declared that Obersteiner had verified Brown-Sequard's experiments.

That Professor Weismann recognises the vital importance to his own theory of the question whether or no mutilations can be transmitted under any circumstances, is evident from a passage on p. 425 of his work, on which he says: "It can hardly be doubted that mutilations are acquired characters; they do not arise from any tendency contained in the germ, but are merely the reaction of the body under certain external influences. They are, as I have recently expressed it, purely somatogenic characters—viz., characters which emanate from the body (soma) only, as opposed to the germ-cells; they are, therefore, characters that do not arise from the germ itself.

"If mutilations must necessarily be transmitted" [which no one that I know of has maintained], "or even if they might occasionally be transmitted" [which cannot, I imagine, be reasonably questioned], "a powerful support would be given to the Lamarckian principle, and the transmission of functional hypertrophy or atrophy would thus become highly probable."

I have not found any further attempt in Professor Weismann's book to deal with the evidence adduced by Mr. Darwin to show that mutilations, if followed by diseases, are sometimes inherited; and I must leave it to the reader to determine how far Professor Weismann has shown reason for rejecting Mr. Darwin's conclusion. I do not, however, dwell upon these facts now as evidence of a transmitted change of bodily form, or of instinct due to use and disuse or habit; what they prove is that the germ- cells within the parent's body do not stand apart from the other cells of the body so completely as Professor Weismann would have us believe, but that, as Professor Hering, of Prague, has aptly said, they echo with more or less frequency and force to the profounder impressions made upon other cells.

I may say that Professor Weismann does not more cavalierly wave aside the mass of evidence collected by Mr. Darwin and a host of other writers, to the effect that mutilations are sometimes inherited, than does Mr. Wallace, who says that, "as regards mutilations, it is generally admitted that they are not inherited, and there is ample evidence on this point." It is indeed generally admitted that mutilations, when not followed by disease, are very rarely, if ever, inherited; and Mr. Wallace's appeal to the "ample evidence" which he alleges to exist on this head, is much as though he should say that there is ample evidence to show that the days are longer in summer than in winter. "Nevertheless," he continues, "a few cases of apparent inheritance of mutilations have been recorded, and these, if trustworthy, are difficulties in the way of the theory." . . . "The often-quoted case of a disease induced by mutilation being inherited (Brown-Sequard's epileptic guinea-pigs) has been discussed by Professor Weismann and shown to be not conclusive. The mutilation itself—a section of certain nerves—was never inherited, but the resulting epilepsy, or a general state of weakness, deformity, or sores, was sometimes inherited. It is, however, possible that the mere injury introduced and encouraged the growth of certain microbes, which, spreading through the organism, sometimes reached the germ-cells, and thus transmitted a diseased condition to the offspring." {35}

I suppose a microbe which made guinea-pigs eat their toes off was communicated to the germ-cells of an unfortunate guinea-pig which had been already microbed by it, and made the offspring bite its toes off too. The microbe has a good deal to answer for.

On the case of the deterioration of horses in the Falkland Islands after a few generations, Professor Weismann says:—

"In such a case we have only to assume that the climate which is unfavourable, and the nutriment which is insufficient for horses, affect not only the animal as a whole but also its germ-cells. This would result in the diminution in size of the germ-cells, the effects upon the offspring being still further intensified by the insufficient nourishment supplied during growth. But such results would not depend upon the transmission by the germ-cells of certain peculiarities due to the unfavourable climate, which only appear in the full-grown horse."

But Professor Weismann does not like such cases, and admits that he cannot explain the facts in connection with the climatic varieties of certain butterflies, except "by supposing the passive acquisition of characters produced by the direct influence of climate."

Nevertheless in his next paragraph but one he calls such cases "doubtful," and proposes that for the moment they should be left aside. He accordingly leaves them, but I have not yet found what other moment he considered auspicious for returning to them. He tells us that "new experiments will be necessary, and that he has himself already begun to undertake them." Perhaps he will give us the results of these experiments in some future book—for that they will prove satisfactory to him can hardly, I think, be doubted. He writes:—

"Leaving on one side, for the moment, these doubtful and insufficiently investigated cases, we may still maintain that the assumption that changes induced by external conditions in the organism as a whole are communicated to the germ-cells after the manner indicated in Darwin's hypothesis of pangenesis, is wholly unnecessary for the explanation of these phenomena. Still we cannot exclude the possibility of such a transmission occasionally occurring, for even if the greater part of the effects must be attributable to natural selection, there might be a smaller part in certain cases which depends on this exceptional factor."

I repeatedly tried to understand Mr. Darwin's theory of pangenesis, and so often failed that I long since gave the matter up in despair. I did so with the less unwillingness because I saw that no one else appeared to understand the theory, and that even Mr. Darwin's warmest adherents regarded it with disfavour. If Mr. Darwin means that every cell of the body throws off minute particles that find their way to the germ-cells, and hence into the new embryo, this is indeed difficult of comprehension and belief. If he means that the rhythms or vibrations that go on ceaselessly in every cell of the body communicate themselves with greater or less accuracy or perturbation, as the case may be, to the cells that go to form offspring, and that since the characteristics of matter are determined by vibrations, in communicating vibrations they in effect communicate matter, according to the view put forward in the last chapter of my book "Luck or Cunning," {36} then we can better understand it. I have nothing, however, to do with Mr. Darwin's theory of pangenesis beyond avoiding the pretence that I understand either the theory itself or what Professor Weismann says about it; all I am concerned with is Professor Weismann's admission, made immediately afterwards, that the somatic cells may, and perhaps sometimes do, impart characteristics to the germ-cells.

"A complete and satisfactory refutation of such an opinion," he continues, "cannot be brought forward at present"; so I suppose we must wait a little longer, but in the meantime we may again remark that, if we admit even occasional communication of changes in the somatic cells to the germ-cells, we have let in the thin end of the wedge, as Mr. Darwin did when he said that use and disuse did a good deal towards modification. Buffon, in his first volume on the lower animals, {37} dwells on the impossibility of stopping the breach once made by admission of variation at all. "If the point," he writes, "were once gained, that among animals and vegetables there had been, I do not say several species, but even a single one, which had been produced in the course of direct descent from another species; if, for example, it could be once shown that the ass was but a degeneration from the horse—then there is no farther limit to be set to the power of Nature, and we should not be wrong in supposing that with sufficient time she could have evolved all other organised forms from one primordial type." So with use and disuse and transmission of acquired characteristics generally—once show that a single structure or instinct is due to habit in preceding generations, and we can impose no limit on the results achievable by accumulation in this respect, nor shall we be wrong in conceiving it as possible that all specialisation, whether of structure or instinct, may be due ultimately to habit.

How far this can be shown to be probable is, of course, another matter, but I am not immediately concerned with this; all I am concerned with now is to show that the germ-cells not unfrequently become permanently affected by events that have made a profound impression upon the somatic cells, in so far that they transmit an obvious reminiscence of the impression to the embryos which they go subsequently towards forming. This is all that is necessary for my case, and I do not find that Professor Weismann, after all, disputes it.

But here, again, comes the difficulty of saying what Professor Weismann does, and what he does not, dispute. One moment he gives all that is wanted for the Lamarckian contention, the next he denies common-sense the bare necessaries of life. For a more exhaustive and detailed criticism of Professor Weismann's position, I would refer the reader to an admirably clear article by Mr. Sidney H. Vines, which appeared in Nature, October 24, 1889. I can only say that while reading Professor Weismann's book, I feel as I do when I read those of Mr. Darwin, and of a good many other writers on biology whom I need not name. I become like a fly in a window-pane. I see the sunshine and freedom beyond, and buzz up and down their pages, ever hopeful to get through them to the fresh air without, but ever kept back by a mysterious something, which I feel but cannot either grasp or see. It was not thus when I read Buffon, Erasmus Darwin, and Lamarck; it is not thus when I read such articles as Mr. Vines's just referred to. Love of self-display, and the want of singleness of mind that it inevitably engenders—these, I suppose, are the sins that glaze the casements of most men's minds; and from these, no matter how hard he tries to free himself, nor how much he despises them, who is altogether exempt?

Finally, then, when we consider the immense mass of evidence referred to briefly, but sufficiently, by Mr. Charles Darwin, and referred to without other, for the most part, than off-hand dismissal by Professor Weismann in the last of the essays that have been recently translated, I do not see how any one who brings an unbiased mind to the question can hesitate as to the side on which the weight of testimony inclines. Professor Weismann declares that "the transmission of mutilations may be dismissed into the domain of fable." {38} If so, then, whom can we trust? What is the use of science at all if the conclusions of a man as competent as I readily admit Mr. Darwin to have been, on the evidence laid before him from countless sources, is to be set aside lightly and without giving the clearest and most cogent explanation of the why and wherefore? When we see a person "ostrichising" the evidence which he has to meet, as clearly as I believe Professor Weismann to be doing, we shall in nine cases out of ten be right in supposing that he knows the evidence to be too strong for him.



THE DEADLOCK IN DARWINISM—PART III

Now let me return to the recent division of biological opinion into two main streams—Lamarckism and Weismannism Both Lamarckians and Weismannists, not to mention mankind in general, admit that the better adapted to its surroundings a living form may be, the more likely it is to outbreed its compeers. The world at large, again, needs not to be told that the normal course is not unfrequently deflected through the fortunes of war; nevertheless, according to Lamarckians and Erasmus-Darwinians, habitual effort, guided by ever-growing intelligence—that is to say, by continued increase of power in the matter of knowing our likes and dislikes—has been so much the main factor throughout the course of organic development, that the rest, though not lost sight of, may be allowed to go without saying. According, on the other hand, to extreme Charles-Darwinians and Weismannists, habit, effort and intelligence acquired during the experience of any one life goes for nothing. Not even a little fraction of it endures to the benefit of offspring. It dies with him in whom it is acquired, and the heirs of a man's body take no interest therein. To state this doctrine is to arouse instinctive loathing; it is my fortunate task to maintain that such a nightmare of waste and death is as baseless as it is repulsive.

The split in biological opinion occasioned by the deadlock to which Charles-Darwinism has been reduced, though comparatively recent, widens rapidly. Ten years ago Lamarck's name was mentioned only as a byword for extravagance; now, we cannot take up a number of Nature without seeing how hot the contention is between his followers and those of Weismann. This must be referred, as I implied earlier, to growing perception that Mr. Darwin should either have gone farther towards Lamarckism or not so far. In admitting use and disuse as freely as he did, he gave Lamarckians leverage for the overthrow of a system based ostensibly on the accumulation of fortunate accidents. In assigning the lion's share of development to the accumulation of fortunate accidents, he tempted fortuitists to try to cut the ground from under Lamarck's feet by denying that the effects of use and disuse can be inherited at all. When the public had once got to understand what Lamarck had intended, and wherein Mr. Charles Darwin had differed from him, it became impossible for Charles-Darwinians to remain where they were, nor is it easy to see what course was open to them except to cast about for a theory by which they could get rid of use and disuse altogether. Weismannism, therefore, is the inevitable outcome of the straits to which Charles-Darwinians were reduced through the way in which their leader had halted between two opinions.

This is why Charles-Darwinians, from Professor Huxley downwards, have kept the difference between Lamarck's opinions and those of Mr. Darwin so much in the background. Unwillingness to make this understood is nowhere manifested more clearly than in Dr. Francis Darwin's life of his father. In this work Lamarck is sneered at once or twice, and told to go away, but there is no attempt to state the two cases side by side; from which, as from not a little else, I conclude that Dr. Francis Darwin has descended from his father with singularly little modification.

Proceeding to the evidence for the transmissions of acquired habits, I will quote two recently adduced examples from among the many that have been credibly attested. The first was contributed to Nature (March 14, 1889) by Professor Marcus M. Hartog, who wrote:—

"A. B. is moderately myopic and very astigmatic in the left eye; extremely myopic in the right. As the left eye gave such bad images for near objects, he was compelled in childhood to mask it, and acquired the habit of leaning his head on his left arm for writing, so as to blind that eye, or of resting the left temple and eye on the hand, with the elbow on the table. At the age of fifteen the eyes were equalised by the use of suitable spectacles, and he soon lost the habit completely and permanently. He is now the father of two children, a boy and a girl, whose vision (tested repeatedly and fully) is emmetropic in both eyes, so that they have not inherited the congenital optical defect of their father. All the same, they have both of them inherited his early acquired habit, and need constant watchfulness to prevent their hiding the left eye when writing, by resting the head on the left forearm or hand. Imitation is here quite out of the question.

"Considering that every habit involves changes in the proportional development of the muscular and osseous systems, and hence probably of the nervous system also, the importance of inherited habits, natural or acquired, cannot be overlooked in the general theory of inheritance. I am fully aware that I shall be accused of flat Lamarckism, but a nickname is not an argument."

To this Professor Ray Lankester rejoined (Nature, March 21, 1889):—

"It is not unusual for children to rest the head on the left forearm or hand when writing, and I doubt whether much value can be attached to the case described by Professor Hartog. The kind of observation which his letter suggests is, however, likely to lead to results either for or against the transmission of acquired characters. An old friend of mine lost his right arm when a schoolboy, and has ever since written with his left. He has a large family and grandchildren, but I have not heard of any of them showing a disposition to left-handedness."

From Nature (March 21, 1889) I take the second instance communicated by Mr. J. Jenner-Weir, who wrote as follows:—

"Mr. Marcus M. Hartog's letter of March 6th, inserted in last week's number (p. 462), is a very valuable contribution to the growing evidence that acquired characters may be inherited. I have long held the view that such is often the case, and I have myself observed several instances of the, at least I may say, apparent fact.

"Many years ago there was a very fine male of the Capra megaceros in the gardens of the Zoological Society. To restrain this animal from jumping over the fence of the enclosure in which he was confined, a long, and heavy chain was attached to the collar round his neck. He was constantly in the habit of taking this chain up by his horns and moving it from one side to another over his back; in doing this he threw his head very much back, his horns being placed in a line with the back. The habit had become quite chronic with him, and was very tiresome to look at. I was very much astonished to observe that his offspring inherited the habit, and although it was not necessary to attach a chain to their necks, I have often seen a young male throwing his horns over his back and shifting from side to side an imaginary chain. The action was exactly the same as that of his ancestor. The case of the kid of this goat appears to me to be parallel to that of child and parent given by Mr. Hartog. I think at the time I made this observation I informed Mr. Darwin of the fact by letter, and he did not accuse me of 'flat Lamarckism.'"

To this letter there was no rejoinder. It may be said, of course, that the action of the offspring in each of these cases was due to accidental coincidence only. Anything can be said, but the question turns not on what an advocate can say, but on what a reasonably intelligent and disinterested jury will believe; granted they might be mistaken in accepting the foregoing stories, but the world of science, like that of commerce, is based on the faith or confidence, which both creates and sustains them. Indeed the universe itself is but the creature of faith, for assuredly we know of no other foundation. There is nothing so generally and reasonably accepted—not even our own continued identity—but questions may be raised about it that will shortly prove unanswerable. We cannot so test every sixpence given us in change as to be sure that we never take a bad one, and had better sometimes be cheated than reduce caution to an absurdity. Moreover, we have seen from the evidence given in my preceding article that the germ-cells issuing from a parent's body can, and do, respond to profound impressions made on the somatic-cells. This being so, what impressions are more profound, what needs engage more assiduous attention than those connected with self-protection, the procuring of food, and the continuation of the species? If the mere anxiety connected with an ill-healing wound inflicted on but one generation is sometimes found to have so impressed the germ-cells that they hand down its scars to offspring, how much more shall not anxieties that have directed action of all kinds from birth till death, not in one generation only but in a longer series of generations than the mind can realise to itself, modify, and indeed control, the organisation of every species?

I see Professor S. H. Vines, in the article on Weismann's theory referred to in my preceding article, says Mr. Darwin "held that it was not the sudden variations due to altered external conditions which become permanent, but those slowly produced by what he termed 'the accumulative action of changed conditions of life.'" Nothing can be more soundly Lamarckian, and nothing should more conclusively show that, whatever else Mr. Darwin was, he was not a Charles-Darwinian; but what evidence other than inferential can from the nature of the case be adduced in support of this, as I believe, perfectly correct judgment? None know better than they who clamour for direct evidence that their master was right in taking the position assigned to him by Professor Vines, that they cannot reasonably look for it. With us, as with themselves, modification proceeds very gradually, and it violates our principles as much as their own to expect visible permanent progress, in any single generation, or indeed in any number of generations of wild species which we have yet had time to observe. Occasionally we can find such cases, as in that of Branchipus stagnalis, quoted by Mr. Wallace, or in that of the New Zealand Kea whose skin, I was assured by the late Sir Julius von Haast, has already been modified as a consequence of its change of food. Here we can show that in even a few generations structure is modified under changed conditions of existence, but as we believe these cases to occur comparatively rarely, so it is still more rarely that they occur when and where we can watch them. Nature is eminently conservative, and fixity of type, even under considerable change of conditions, is surely more important for the well-being of any species than an over-ready power of adaptation to, it may be, passing changes. There could be no steady progress if each generation were not mainly bound by the traditions of those that have gone before it. It is evolution and not incessant revolution that both parties are upholding; and this being so, rapid visible modification must be the exception, not the rule. I have quoted direct evidence adduced by competent observers, which is, I believe, sufficient to establish the fact that offspring can be and is sometimes modified by the acquired habits of a progenitor. I will now proceed to the still more, as it appears to me, cogent proof afforded by general considerations.

What, let me ask, are the principal phenomena of heredity? There must be physical continuity between parent, or parents, and offspring, so that the offspring is, as Erasmus Darwin well said, a kind of elongation of the life of the parent.

Erasmus Darwin put the matter so well that I may as well give his words in full; he wrote:—

"Owing to the imperfection of language the offspring is termed a new animal, but is in truth a branch or elongation of the parent, since a part of the embryon animal is, or was, a part of the parent, and therefore, in strict language, cannot be said to be entirely new at the time of its production; and therefore it may retain some of the habits of the parent system.

"At the earliest period of its existence the embryon would seem to consist of a living filament with certain capabilities of irritation, sensation, volition, and association, and also with some acquired habits or propensities peculiar to the parent; the former of these are in common with other animals; the latter seem to distinguish or produce the kind of animal, whether man or quadruped, with the similarity of feature or form to the parent." {39}

Those who accept evolution insist on unbroken physical continuity between the earliest known life and ourselves, so that we both are and are not personally identical with the unicellular organism from which we have descended in the course of many millions of years, exactly in the same way as an octogenarian both is and is not personally identical with the microscopic impregnate ovum from which he grew up. Everything both is and is not. There is no such thing as strict identity between any two things in any two consecutive seconds. In strictness they are identical and yet not identical, so that in strictness they violate a fundamental rule of strictness—namely, that a thing shall never be itself and not itself at one and the same time; we must choose between logic and dealing in a practical spirit with time and space; it is not surprising, therefore, that logic, in spite of the show of respect outwardly paid to her, is told to stand aside when people come to practice. In practice identity is generally held to exist where continuity is only broken slowly and piecemeal, nevertheless, that occasional periods of even rapid change are not held to bar identity, appears from the fact that no one denies this to hold between the microscopically small impregnate ovum and the born child that springs from it, nor yet, therefore, between the impregnate ovum and the octogenarian into which the child grows; for both ovum and octogenarian are held personally identical with the newborn baby, and things that are identical with the same are identical with one another.

The first, then, and most important element of heredity is that there should be unbroken continuity, and hence sameness of personality, between parents and offspring, in neither more nor less than the same sense as that in which any other two personalities are said to be the same. The repetition, therefore, of its developmental stages by any offspring must be regarded as something which the embryo repeating them has already done once, in the person of one or other parent; and if once, then, as many times as there have been generations between any given embryo now repeating it, and the point in life from which we started—say, for example, the amoeba. In the case of asexually and sexually produced organisms alike, the offspring must be held to continue the personality of the parent or parents, and hence on the occasion of every fresh development, to be repeating something which in the person of its parent or parents it has done once, and if once, then any number of times, already.

It is obvious, therefore, that the germ-plasm (or whatever the fancy word for it may be) of any one generation is as physically identical with the germ-plasm of its predecessor as any two things can be. The difference between Professor Weismann and, we will say, Heringians consists in the fact that the first maintains the new germ-plasm when on the point of repeating its developmental processes to take practically no cognisance of anything that has happened to it since the last occasion on which it developed itself; while the latter maintain that offspring takes much the same kind of account of what has happened to it in the persons of its parents since the last occasion on which it developed itself, as people in ordinary life take of things that happen to them. In daily life people let fairly normal circumstances come and go without much heed as matters of course. If they have been lucky they make a note of it and try to repeat their success. If they have been unfortunate but have recovered rapidly they soon forget it; if they have suffered long and deeply they grizzle over it and are scared and scarred by it for a long time. The question is one of cognisance or non-cognisance on the part of the new germs, of the more profound impressions made on them while they were one with their parents, between the occasion of their last preceding development, and the new course on which they are about to enter. Those who accept the theory put forward independently by Professor Hering of Prague (whose work on this subject is translated in my book, "Unconscious Memory") {40} and by myself in "Life and Habit," {41} believe in cognizance, as do Lamarckians generally. Weismannites, and with them the orthodoxy of English science, find non-cognisance more acceptable.

If the Heringian view is accepted, that heredity is only a mode of memory, and an extension of memory from one generation to another, then the repetition of its development by any embryo thus becomes only the repetition of a lesson learned by rote; and, as I have elsewhere said, our view of life is simplified by finding that it is no longer an equation of, say, a hundred unknown quantities, but of ninety-nine only, inasmuch as two of the unknown quantities prove to be substantially identical. In this case the inheritance of acquired characteristics cannot be disputed, for it is postulated in the theory that each embryo takes note of, remembers and is guided by the profounder impressions made upon it while in the persons of its parents, between its present and last preceding development. To maintain this is to maintain use and disuse to be the main factors throughout organic development; to deny it is to deny that use and disuse can have any conceivable effect. For the detailed reasons which led me to my own conclusions I must refer the reader to my books, "Life and Habit" {42} and "Unconscious Memory," {42} the conclusions of which have been often adopted, but never, that I have seen, disputed. A brief resume of the leading points in the argument is all that space will here allow me to give.

We have seen that it is a first requirement of heredity that there shall be physical continuity between parents and offspring. This holds good with memory. There must be continued identity between the person remembering and the person to whom the thing that is remembered happened. We cannot remember things that happened to some one else, and in our absence. We can only remember having heard of them. We have seen, however, that there is as much bona-fide sameness of personality between parents and offspring up to the time at which the offspring quits the parent's body, as there is between the different states of the parent himself at any two consecutive moments; the offspring therefore, being one and the same person with its progenitors until it quits them, can be held to remember what happened to them within, of course, the limitations to which all memory is subject, as much as the progenitors can remember what happened earlier to themselves. Whether it does so remember can only be settled by observing whether it acts as living beings commonly do when they are acting under guidance of memory. I will endeavour to show that, though heredity and habit based on memory go about in different dresses, yet if we catch them separately—for they are never seen together—and strip them there is not a mole nor strawberry-mark, nor trick nor leer of the one, but we find it in the other also.

What are the moles and strawberry-marks of habitual action, or actions remembered and thus repeated? First, the more often we repeat them the more easily and unconsciously we do them. Look at reading, writing, walking, talking, playing the piano, &c.; the longer we have practised any one of these acquired habits, the more easily, automatically and unconsciously, we perform it. Look, on the other hand, broadly, at the three points to which I called attention in "Life and Habit":—

I. That we are most conscious of and have most control over such habits as speech, the upright position, the arts and sciences—which are acquisitions peculiar to the human race, always acquired after birth, and not common to ourselves and any ancestor who had not become entirely human.

II. That we are less conscious of and have less control over eating and drinking [provided the food be normal], swallowing, breathing, seeing, and hearing—which were acquisitions of our prehuman ancestry, and for which we had provided ourselves with all the necessary apparatus before we saw light, but which are still, geologically speaking, recent.

III. That we are most unconscious of and have least control over our digestion and circulation—powers possessed even by our invertebrate ancestry, and, geologically speaking, of extreme antiquity.

I have put the foregoing very broadly, but enough is given to show the reader the gist of the argument. Let it be noted that disturbance and departure, to any serious extent, from normal practice tends to induce resumption of consciousness even in the case of such old habits as breathing, seeing, and hearing, digestion and the circulation of the blood. So it is with habitual actions in general. Let a player be never so proficient on any instrument, he will be put out if the normal conditions under which he plays are too widely departed from, and will then do consciously, if indeed he can do it at all, what he had hitherto been doing unconsciously. It is an axiom as regards actions acquired after birth, that we never do them automatically save as the result of long practice; the stages in the case of any acquired facility, the inception of which we have been able to watch, have invariably been from a nothingness of ignorant impotence to a little somethingness of highly self-conscious, arduous performance, and thence to the unselfconsciousness of easy mastery. I saw one year a poor blind lad of about eighteen sitting on a wall by the wayside at Varese, playing the concertina with his whole body, and snorting like a child. The next year the boy no longer snorted, and he played with his fingers only; the year after that he seemed hardly to know whether he was playing or not, it came so easily to him. I know no exception to this rule. Where is the intricate and at one time difficult art in which perfect automatic ease has been reached except as the result of long practice? If, then, wherever we can trace the development of automatism we find it to have taken this course, is it not most reasonable to infer that it has taken the same even when it has risen in regions that are beyond our ken? Ought we not, whenever we see a difficult action performed, automatically to suspect antecedent practice? Granted that without the considerations in regard to identity presented above it would not have been easy to see where a baby of a day old could have had the practice which enables it to do as much as it does unconsciously, but even without these considerations it would have been more easy to suppose that the necessary opportunities had not been wanting, than that the easy performance could have been gained without practice and memory.

When I wrote "Life and Habit" (originally published in 1877) I said in slightly different words:—

"Shall we say that a baby of a day old sucks (which involves the whole principle of the pump and hence a profound practical knowledge of the laws of pneumatics and hydrostatics), digests, oxygenises its blood—millions of years before any one had discovered oxygen—sees and hears, operations that involve an unconscious knowledge of the facts concerning optics and acoustics compared with which the conscious discoveries of Newton are insignificant—shall we say that a baby can do all these things at once, doing them so well and so regularly without being even able to give them attention, and yet without mistake, and shall we also say at the same time that it has not learnt to do them, and never did them before?

"Such an assertion would contradict the whole experience of mankind."

I have met with nothing during the thirteen years since the foregoing was published that has given me any qualms about its soundness. From the point of view of the law courts and everyday life it is, of course, nonsense; but in the kingdom of thought, as in that of heaven, there are many mansions, and what would be extravagance in the cottage or farmhouse, as it were, of daily practice, is but common decency in the palace of high philosophy, wherein dwells evolution. If we leave evolution alone, we may stick to common practice and the law courts; touch evolution and we are in another world; not higher, not lower, but different as harmony from counterpoint. As, however, in the most absolute counterpoint there is still harmony, and in the most absolute harmony still counterpoint, so high philosophy should be still in touch with common sense, and common sense with high philosophy.

The common-sense view of the matter to people who are not over-curious and to whom time is money, will be that a baby is not a baby until it is born, and that when born it should be born in wedlock. Nevertheless, as a sop to high philosophy, every baby is allowed to be the offspring of its father and mother.

The high-philosophy view of the matter is that every human being is still but a fresh edition of the primordial cell with the latest additions and corrections; there has been no leap nor break in continuity anywhere; the man of to-day is the primordial cell of millions of years ago as truly as he is the himself of yesterday; he can only be denied to be the one on grounds that will prove him not to be the other. Every one is both himself and all his direct ancestors and descendants as well; therefore, if we would be logical, he is one also with all his cousins, no matter how distant, for he and they are alike identical with the primordial cell, and we have already noted it as an axiom that things which are identical with the same are identical with one another. This is practically making him one with all living things, whether animal or vegetable, that ever have existed or ever will—something of all which may have been in the mind of Sophocles when he wrote:—

"Nor seest thou yet the gathering hosts of ill That shall en-one thee both with thine own self And with thine offspring."

And all this has come of admitting that a man may be the same person for two days running! As for sopping common sense it will be enough to say that these remarks are to be taken in a strictly scientific sense, and have no appreciable importance as regards life and conduct. True they deal with the foundations on which all life and conduct are based, but like other foundations they are hidden out of sight, and the sounder they are, the less we trouble ourselves about them.

What other main common features between heredity and memory may we note besides the fact that neither can exist without that kind of physical continuity which we call personal identity? First, the development of the embryo proceeds in an established order; so must all habitual actions based on memory. Disturb the normal order and the performance is arrested. The better we know "God save the Queen," the less easily can we play or sing it backwards. The return of memory again depends on the return of ideas associated with the particular thing that is remembered—we remember nothing but for the presence of these, and when enough of these are presented to us we remember everything. So, if the development of an embryo is due to memory, we should suppose the memory of the impregnate ovum to revert not to yesterday, when it was in the persons of its parents, but to the last occasion on which it was an impregnate ovum. The return of the old environment and the presence of old associations would at once involve recollection of the course that should be next taken, and the same should happen throughout the whole course of development. The actual course of development presents precisely the phenomena agreeable with this. For fuller treatment of this point I must refer the reader to the chapter on the abeyance of memory in my book "Life and Habit," already referred to.

Secondly, we remember best our last few performances of any given kind, so our present performance will probably resemble some one or other of these; we remember our earlier performances by way of residuum only, but every now and then we revert to an earlier habit. This feature of memory is manifested in heredity by the way in which offspring commonly resembles most its nearer ancestors, but sometimes reverts to earlier ones. Brothers and sisters, each as it were giving their own version of the same story, but in different words, should generally resemble each other more closely than more distant relations. And this is what actually we find.

Thirdly, the introduction of slightly new elements into a method already established varies it beneficially; the new is soon fused with the old, and the monotony ceases to be oppressive. But if the new be too foreign, we cannot fuse the old and the new—nature seeming to hate equally too wide a deviation from ordinary practice and none at all. This fact reappears in heredity as the beneficial effects of occasional crossing on the one hand, and on the other, in the generally observed sterility of hybrids. If heredity be an affair of memory, how can an embryo, say of a mule, be expected to build up a mule on the strength of but two mule-memories? Hybridism causes a fault in the chain of memory, and it is to this cause that the usual sterility of hybrids must be referred.

Fourthly, it requires many repeated impressions to fix a method firmly, but when it has been engrained into us we cease to have much recollection of the manner in which it came to be so, or indeed of any individual repetition, but sometimes a single impression, if prolonged as well as profound, produces a lasting impression and is liable to return with sudden force, and then to go on returning to us at intervals. As a general rule, however, abnormal impressions cannot long hold their own against the overwhelming preponderance of normal authority. This appears in heredity as the normal non-inheritance of mutilations on the one hand, and on the other as their occasional inheritance in the case of injuries followed by disease.

Fifthly, if heredity and memory are essentially the same, we should expect that no animal would develop new structures of importance after the age at which its species begins ordinarily to continue its race; for we cannot suppose offspring to remember anything that happens to the parent subsequently to the parent's ceasing to contain the offspring within itself. From the average age, therefore, of reproduction, offspring should cease to have any farther steady, continuous memory to fall back upon; what memory there is should be full of faults, and as such unreliable. An organism ought to develop as long as it is backed by memory—that is to say, until the average age at which reproduction begins; it should then continue to go for a time on the impetus already received, and should eventually decay through failure of any memory to support it, and tell it what to do. This corresponds absolutely with what we observe in organisms generally, and explains, on the one hand, why the age of puberty marks the beginning of completed development—a riddle hitherto not only unexplained but, so far as I have seen, unasked; it explains, on the other hand, the phenomena of old age—hitherto without even attempt at explanation.