Essays on Life, Art and Science Part 10

"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 s.h.i.+fting 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 a.s.suredly we know of no other foundation. There is nothing so generally and reasonably accepted--not even our own continued ident.i.ty--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 a.s.siduous 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 acc.u.mulative 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 a.s.signed 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 a.s.sured 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, pa.s.sing 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 princ.i.p.al 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 a.s.sociation, 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 ident.i.ty 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 s.p.a.ce; 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 ident.i.ty 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 ident.i.ty, 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 repet.i.tion, 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 as.e.xually and s.e.xually 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 circ.u.mstances 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 repet.i.tion of its development by any embryo thus becomes only the repet.i.tion 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 quant.i.ties, but of ninety-nine only, inasmuch as two of the unknown quant.i.ties 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 s.p.a.ce 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 ident.i.ty 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 ident.i.ty 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 a.s.sertion 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 ident.i.ty? 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 "G.o.d save the Queen," the less easily can we play or sing it backwards. The return of memory again depends on the return of ideas a.s.sociated 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 a.s.sociations 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 repet.i.tion, 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 p.u.b.erty 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.

Sixthly, those organisms that are the longest in reaching maturity should on the average be the longest-lived, for they will have received the most momentous impulse from the weight of memory behind them. This harmonises with the latest opinion as to the facts. In his article on Weismann in the _Contemporary Review_ for May 1890, Mr. Romanes writes: "Professor Weismann has shown that there is throughout the metazoa a general correlation between the natural lifetime of individuals composing any given species, and the age at which they reach maturity or first become capable of procreation." This, I believe, has been the conclusion generally arrived at by biologists for some years past.

Lateness, then, in the average age of reproduction appears to be the principle underlying longevity. There does not appear at first sight to be much connection between such distinct and apparently disconnected phenomena as 1, the orderly normal progress of development; 2, atavism and the resumption of feral characteristics; 3, the more ordinary resemblance _inter se_ of nearer relatives; 4, the benefit of an occasional cross, and the usual sterility of hybrids; 5, the unconsciousness with which alike bodily development and ordinary physiological functions proceed, so long as they are normal; 6, the ordinary non-inheritance, but occasional inheritance of mutilations; 7, the fact that p.u.b.erty indicates the approach of maturity; 8, the phenomena of middle life and old age; 9, the principle underlying longevity. These phenomena have no conceivable bearing on one another until heredity and memory are regarded as part of the same story.

Identify these two things, and I know no phenomenon of heredity that does not immediately become infinitely more intelligible. Is it conceivable that a theory which harmonises so many facts. .h.i.therto regarded as without either connection or explanation should not deserve at any rate consideration from those who profess to take an interest in biology?

It is not as though the theory were unknown, or had been condemned by our leading men of science. Professor Ray Lankester introduced it to English readers in an appreciative notice of Professor Hering's address, which appeared in _Nature_, July 18, 1876. He wrote to the _Athenaeum_, March 24, 1884, and claimed credit for having done so, but I do not believe he has ever said more in public about it than what I have here referred to.

Mr. Romanes did indeed try to crush it in _Nature_, January 27, 1881, but in 1883, in his "Mental Evolution in Animals," he adopted its main conclusion without acknowledgment. The _Athenaeum_, to my unbounded surprise, called him to task for this (March 1, 1884), and since that time he has given the Heringian theory a sufficiently wide berth. Mr.

Wallace showed himself favourably enough disposed towards the view that heredity and memory are part of the same story when he reviewed my book "Life and Habit" in _Nature_, March 27, 1879, but he has never since betrayed any sign of being aware that such a theory existed. Mr. Herbert Spencer wrote to the _Athenaeum_ (April 5, 1884), and claimed the theory for himself, but, in spite of his doing this, he has never, that I have seen, referred to the matter again. I have dealt sufficiently with his claim in my book, "Luck or Cunning." {43} Lastly, Professor Hering himself has never that I know of touched his own theory since the single short address read in 1870, and translated by me in 1881. Every one, even its originator, except myself, seems afraid to open his mouth about it. Of course the inference suggests itself that other people have more sense than I have. I readily admit it; but why have so many of our leaders shown such a strong hankering after the theory, if there is nothing in it?

The deadlock that I have pointed out as existing in Darwinism will, I doubt not, lead ere long to a consideration of Professor Hering's theory.

English biologists are little likely to find Weismann satisfactory for long, and if he breaks down there is nothing left for them but Lamarck, supplemented by the important and elucidatory corollary on his theory proposed by Professor Hering. When the time arrives for this to obtain a hearing it will be confirmed, doubtless, by arguments clearer and more forcible than any I have been able to adduce; I shall then be delighted to resign the champions.h.i.+p which till then I shall continue, as for some years past, to have much pleasure in sustaining. Heretofore my satisfaction has mainly lain in the fact that more of our prominent men of science have seemed anxious to claim the theory than to refute it; in the confidence thus engendered I leave it to any fuller consideration which the outline I have above given may incline the reader to bestow upon it.

Footnotes:

{1} Published in the _Universal Review_, July 1888.

{2} Published in the _Universal Review_, December 1890.

{3} Published in the _Universal Review_, May 1889. As I have several times been asked if the letters here reprinted were not fabricated by Butler himself, I take this opportunity of stating that they are authentic in every particular, and that the originals are now in my possession.--R. A. S.

{4} An address delivered at the Somerville Club, February 27, 1895.

{5} "The Foundations of Belief," by the Right Hon. A. J. Balfour.