WHAT WE SHOULD EXPECT TO FIND IF DIFFERENTIATIONS OF STRUCTURE AND INSTINCT ARE MAINLY DUE TO MEMORY
To repeat briefly;--we remember best our last few performances of any given kind, and our present performance is most likely to resemble one or other of these; we only remember our earlier performances by way of residuum; nevertheless, at times, some older feature is liable to reappear.
We take our steps in the same order on each successive occasion, and are for the most part incapable of changing that order.
The introduction of slightly new elements into our manner is attended with benefit; the new can be fused with the old, and the monotony of our action is relieved. But if the new element is too foreign, we cannot fuse the old and new--nature seeming equally to hate too wide a deviation from our ordinary practice, and no deviation at all. Or, in plain English--if any one gives us a new idea which is not too far ahead of us, such an idea is often of great service to us, and may give new life to our work--in fact, we soon go back, unless we more or less frequently come into contact with new ideas, and are capable of understanding and making use of them; if; on the other hand, they are too new, and too little led up to, so that we find them too strange and hard to be able to understand them and adopt them, then they put us out, with every degree of completeness--from simply causing us to fail in this or that particular part, to rendering us incapable of even trying to do our work at all, from pure despair of succeeding.
It requires many repetitions to fix an impression firmly; but when it is fixed, we cease to have much recollection of the manner in which it came to be so, or of any single and particular recurrence.
Our memory is mainly called into action by force of association and similarity in the surroundings. We want to go on doing what we did when we were last as we are now, and we forget what we did in the meantime.
These rules, however, are liable to many exceptions; as for example, that a single and apparently not very extraordinary occurrence may sometimes produce a lasting impression, and be liable to return with sudden force at some distant time, and then to go on returning to us at intervals. Some incidents, in fact, we know not how nor why, dwell with us much longer than others which were apparently quite as noteworthy or perhaps more so.
Now I submit that if the above observations are just, and if, also, the offspring, after having become a new and separate personality, yet retains so much of the old identity of which it was once indisputably part, that it remembers what it did when it was part of that identity as soon as it finds itself in circumstances which are calculated to refresh its memory owing to their similarity to certain antecedent ones, then we should expect to find:-
I. That offspring should, as a general rule, resemble its own most immediate progenitors; that is to say, that it should remember best what it has been doing most recently. The memory being a fusion of its recollections of what it did, both when it was its father and also when it was its mother, the offspring should have a very common tendency to resemble both parents, the one in some respects, and the other in others; but it might also hardly less commonly show a more marked recollection of the one history than of the other, thus more distinctly resembling one parent than the other. And this is what we observe to be the case. Not only so far as that the offspring is almost invariably either male or female, and generally resembles rather the one parent than the other, but also that in spite of such preponderance of one set of recollections, the sexual characters and instincts of the OPPOSITE sex appear, whether in male or female, though undeveloped and incapable of development except by abnormal treatment, such as has occasionally caused milk to be developed in the mammary glands of males; or by mutilation, or failure of sexual instinct through age, upon which, male characteristics frequently appear in the females of any species.
Brothers and sisters, each giving their own version of the same story, though in different words, should resemble each other more closely than more distant relations. This too we see.
But it should frequently happen that offspring should resemble its penultimate rather than its latest phase, and should thus be more like a grand-parent than a parent; for we observe that we very often repeat a performance in a manner resembling that of some earlier, but still recent, repetition; rather than on the precise lines of our very last performance. First-cousins may in this case resemble each other more closely than brothers and sisters.
More especially, we should not expect very successful men to be fathers of particularly gifted children; for the best men are, as it were, the happy thoughts and successes of the race--nature's "flukes," so to speak, in her onward progress. No creature can repeat at will, and immediately, its highest flight. It needs repose. The generations are the essays of any given race towards the highest ideal which it is as yet able to see ahead of itself, and this, in the nature of things, cannot be very far; so that we should expect to see success followed by more or less failure, and failure by success--a very successful creature being a GREAT "fluke." And this is what we find.
In its earlier stages the embryo should be simply conscious of a general method of procedure on the part of its forefathers, and should, by reason of long practice, compress tedious and complicated histories into a very narrow compass, remembering no single performance in particular. For we observe this in nature, both as regards the sleight-of-hand which practice gives to those who are thoroughly familiar with their business, and also as regards the fusion of remoter memories into a general residuum.
II. We should expect to find that the offspring, whether in its embryonic condition, or in any stage of development till it has reached maturity, should adopt nearly the same order in going through all its various stages. There should be such slight variations as are inseparable from the repetition of any performance by a living being (as contrasted with a machine), but no more. And this is what actually happens. A man may cut his wisdom-teeth a little later than he gets his beard and whiskers, or a little earlier; but on the whole, he adheres to his usual order, and is completely set off his balance, and upset in his performance, if that order be interfered with suddenly. It is, however, likely that gradual modifications of order have been made and then adhered to.
After any animal has reached the period at which it ordinarily begins to continue its race, we should expect that it should show little further power of development, or, at any rate, that few great changes of structure or fresh features should appear; 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 would cease to have any further experience on which to fall back, and would thus continue to make the best use of what it already knew, till memory failing either in one part or another, the organism would begin to decay.
To this cause must be referred the phenomena of old age, which interesting subject I am unable to pursue within the limits of this volume.
Those creatures who are longest in reaching maturity might be expected also to be the longest lived; I am not certain, however, how far what is called alternate generation militates against this view, but I do not think it does so seriously.
Lateness of marriage, provided the constitution of the individuals marrying is in no respect impaired, should also tend to longevity.
I believe that all the above will be found sufficiently well supported by facts. If so, when we feel that we are getting old we should try and give our cells such treatment as they will find it most easy to understand, through their experience of their own individual life, which, however, can only guide them inferentially, and to a very small extent; and throughout life we should remember the important bearing which memory has upon health, and both occasionally cross the memories of our component cells with slightly new experiences, and be careful not to put them either suddenly or for long together into conditions which they will not be able to understand. Nothing is so likely to make our cells forget themselves, as neglect of one or other of these considerations. They will either fail to recognise themselves completely, in which case we shall die; or they will go on strike, more or less seriously as the case may be, or perhaps, rather, they will try and remember their usual course, and fail; they will therefore try some other, and will probably make a mess of it, as people generally do when they try to do things which they do not understand, unless indeed they have very exceptional capacity.
It also follows that when we are ill, our cells being in such or such a state of mind, and inclined to hold a corresponding opinion with more or less unreasoning violence, should not be puzzled more than they are puzzled already, by being contradicted too suddenly; for they will not be in a frame of mind which can understand the position of an open opponent: they should therefore either be let alone, if possible, without notice other than dignified silence, till their spleen is over, and till they have remembered themselves; or they should be reasoned with as by one who agrees with them, and who is anxious to see things as far as possible from their own point of view. And this is how experience teaches that we must deal with monomaniacs, whom we simply infuriate by contradiction, but whose delusion we can sometimes persuade to hang itself if we but give it sufficient rope. All which has its bearing upon politics, too, at much sacrifice, it may be, of political principles, but a politician who cannot see principles where principle-mongers fail to see them, is a dangerous person.
I may say, in passing, that the reason why a small wound heals, and leaves no scar, while a larger one leaves a mark which is more or less permanent, may be looked for in the fact that when the wound is only small, the damaged cells are snubbed, so to speak, by the vast majority of the unhurt cells in their own neighbourhood. When the wound is more serious they can stick to it, and bear each other out that they were hurt.
III. We should expect to find a predominance of sexual over asexual generation, in the arrangements of nature for continuing her various species, inasmuch as two heads are better than one, and a locus poenitentiae is thus given to the embryo--an opportunity of correcting the experience of one parent by that of the other. And this is what the more intelligent embryos may be supposed to do; for there would seem little reason to doubt that there are clever embryos and stupid embryos, with better or worse memories, as the case may be, of how they dealt with their protoplasm before, and better or worse able to see how they can do better now; and that embryos differ as widely in intellectual and moral capacity, and in a general sense of the fitness of things, and of what will look well into the bargain, as those larger embryos--to wit, children--do. Indeed it would seem probable that all our mental powers must go through a quasi-embryological condition, much as the power of keeping, and wisely spending, money must do so, and that all the qualities of human thought and character are to be found in the embryo.
Those who have observed at what an early age differences of intellect and temper show themselves in the young, for example, of cats and dogs, will find it difficult to doubt that from the very moment of impregnation, and onward, there has been a corresponding difference in the embryo--and that of six unborn puppies, one, we will say, has been throughout the whole process of development more sensible and better looking--a nicer embryo, in fact--than the others.
IV. We should expect to find that all species, whether of plants or animals, are occasionally benefited by a cross; but we should also expect that a cross should have a tendency to introduce a disturbing element, if it be too wide, inasmuch as the offspring would be pulled hither and thither by two conflicting memories or advices, much as though a number of people speaking at once were without previous warning to advise an unhappy performer to vary his ordinary performance--one set of people telling him he has always hitherto done thus, and the other saying no less loudly that he did it thus;-- and he were suddenly to become convinced that they each spoke the truth. In such a case he will either completely break down, if the advice be too conflicting, or if it be less conflicting, he may yet be so exhausted by the one supreme effort of fusing these experiences that he will never be able to perform again; or if the conflict of experience be not great enough to produce such a permanent effect as this, it will yet, if it be at all serious, probably damage his performances on their next several occasions, through his inability to fuse the experiences into a harmonious whole, or, in other words, to understand the ideas which are prescribed to him; for to fuse is only to understand.
And this is absolutely what we find in fact. Mr. Darwin writes concerning hybrids and first crosses:- "The male element may reach the female element, but be incapable of causing an embryo to be developed, as seems to have been the case with some of Thuret's experiments on Fuci. No explanation can be given of these facts any more than why certain trees cannot be grafted on others."
I submit that what I have written above supplies a very fair prima facie explanation.
Mr. Darwin continues:-
"Lastly, an embryo may be developed, and then perish at an early period. This latter alternative has not been sufficiently attended to; but I believe, from observations communicated to me by Mr. Hewitt, who has had great experience in hybridising pheasants and fowls, that the early death of the embryo is a very frequent cause of sterility in first crosses. Mr. Salter has recently given the results of an examination of about five hundred eggs produced from various crosses between three species of Gallus and their hybrids; the majority of these eggs had been fertilised; and in the majority of the fertilised eggs, the embryos had either been partially developed, and had then perished, or had become nearly mature, but the young chickens had been unable to break through the shell. Of the chickens which were born more than four-fifths died within the first few days, or at latest weeks, 'without any obvious cause, apparently from mere inability to live,' so that from the five hundred eggs only twelve chickens were reared" ("Origin of Species," 249, ed. 1876).
No wonder the poor creatures died, distracted as they were by the internal tumult of conflicting memories. But they must have suffered greatly; and the Society for the Prevention of Cruelty to Animals may perhaps think it worth while to keep an eye even on the embryos of hybrids and first crosses. Five hundred creatures puzzled to death is not a pleasant subject for contemplation. Ten or a dozen should, I think, be sufficient for the future.
As regards plants, we read:-
"Hybridised embryos probably often perish in like manner . . . of which fact Max Wichura has given some striking cases with hybrid willows . . . It may be here worth noticing, that in some cases of parthenogenesis, the embryos within the eggs of silk moths, which have not been fertilised, pass through their early stages of development, and then perish like the embryos produced by a cross between distinct species" (Ibid).
This last fact would at first sight seem to make against me, but we must consider that the presence of a double memory, provided it be not too conflicting, would be a part of the experience of the silk moth's egg, which might be then as fatally puzzled by the monotony of a single memory as it would be by two memories which were not sufficiently like each other. So that failure here must be referred to the utter absence of that little internal stimulant of slightly conflicting memory which the creature has always hitherto experienced, and without which it fails to recognise itself. In either case, then, whether with hybrids or in cases of parthenogenesis, the early death of the embryo is due to inability to recollect, owing to a fault in the chain of associated ideas. All the facts here given are an excellent illustration of the principle, elsewhere insisted upon by Mr. Darwin, that ANY great and sudden change of surroundings has a tendency to induce sterility; on which head he writes ("Plants and Animals under Domestication," vol. ii. p. 143, ed. 1875):-
"It would appear that any change in the habits of life, whatever their habits may be, if great enough, tends to affect in an inexplicable manner the powers of reproduction."
And again on the next page:-
"Finally, we must conclude, limited though the conclusion is, that changed conditions of life have an especial power of acting injuriously on the reproductive system. The whole case is quite peculiar, for these organs, though not diseased, are thus rendered incapable of performing their proper functions, or perform them imperfectly."
One is inclined to doubt whether the blame may not rest with the inability on the part of the creature reproduced to recognise the new surroundings, and hence with its failing to know itself. And this seems to be in some measure supported--but not in such a manner as I can hold to be quite satisfactory--by the continuation of the passage in the "Origin of Species," from which I have just been quoting--for Mr. Darwin goes on to say:-
"Hybrids, however, are differently circumstanced before and after birth. When born, and living in a country where their parents live, they are generally placed under suitable conditions of life. But a hybrid partakes of only half of the nature and condition of its mother; it may therefore before birth, as long as it is nourished within its mother's womb, or within the egg or seed produced by its mother, be exposed to conditions in some degree unsuitable, and consequently be liable to perish at an early period . . . " After which, however, the conclusion arrived at is, that, "after all, the cause more probably lies in some imperfection in the original act of impregnation, causing the embryo to be imperfectly developed rather than in the conditions to which it is subsequently exposed." A conclusion which I am not prepared to accept.
Returning to my second alternative, that is to say, to the case of hybrids which are born well developed and healthy, but nevertheless perfectly sterile, it is less obvious why, having succeeded in understanding the conflicting memories of their parents, they should fail to produce offspring; but I do not think the reader will feel surprised that this should be the case. The following anecdote, true or false, may not be out of place here:-
"Plutarch tells us of a magpie, belonging to a barber at Rome, which could imitate to a nicety almost every word it heard. Some trumpets happened one day to be sounded before the shop, and for a day or two afterwards the magpie was quite mute, and seemed pensive and melancholy. All who knew it were greatly surprised at its silence; and it was supposed that the sound of the trumpets had so stunned it as to deprive it at once of both voice and hearing. It soon appeared, however, that this was far from being the case; for, says Plutarch, the bird had been all the time occupied in profound meditation, studying how to imitate the sound of the trumpets; and when at last master of it, the magpie, to the astonishment of all its friends, suddenly broke its long silence by a perfect imitation of the flourish of trumpets it had heard, observing with the greatest exactness all the repetitions, stops, and changes. THE ACQUISITION OF THIS LESSON HAD, HOWEVER, EXHAUSTED THE WHOLE OF THE MAGPIE'S STOCK OF INTELLECT, FOR IT MADE IT FORGET EVERYTHING IT HAD LEARNED BEFORE" ("Percy Anecdotes," Instinct, p. 166).
Or, perhaps, more seriously, the memory of every impregnate ovum from which every ancestor of a mule, for example, has sprung, has reverted to a very long period of time during which its forefathers have been creatures like that which it is itself now going to become: thus, the impregnate ovum from which the mule's father was developed remembered nothing but horse memories; but it felt its faith in these supported by the recollection of a VAST NUMBER of previous generations, in which it was, to all intents and purposes, what it now is. In like manner, the impregnate ovum from which the mule's mother was developed would be backed by the assurance that it had done what it is going to do now a hundred thousand times already. All would thus be plain sailing. A horse and a donkey would result. These two are brought together; an impregnate ovum is produced which finds an unusual conflict of memory between the two lines of its ancestors, nevertheless, being accustomed to SOME conflict, it manages to get over the difficulty, AS ON EITHER SIDE IT FINDS ITSELF BACKED BY A VERY LONG SERIES OF SUFFICIENTLY STEADY MEMORY. A mule results--a creature so distinctly different from either horse or donkey, that reproduction is baffled, owing to the creature's having nothing but its own knowledge of itself to fall back upon, behind which there comes an immediate dislocation, or fault of memory, which is sufficient to bar identity, and hence reproduction, by rendering too severe an appeal to reason necessary--for no creature can reproduce itself on the shallow foundation which reason can alone give. Ordinarily, therefore, the hybrid, or the spermatozoon or ovum, which it may throw off (as the case may be), finds one single experience too small to give it the necessary faith, on the strength of which even to try to reproduce itself. In other cases the hybrid itself has failed to be developed; in others the hybrid, or first cross, is almost fertile; in others it is fertile, but produces depraved issue. The result will vary with the capacities of the creatures crossed, and the amount of conflict between their several experiences.
The above view would remove all difficulties out of the way of evolution, in so far as the sterility of hybrids is concerned. For it would thus appear that this sterility has nothing to do with any supposed immutable or fixed limits of species, but results simply from the same principle which prevents old friends, no matter how intimate in youth, from returning to their old intimacy after a lapse of years, during which they have been subjected to widely different influences, inasmuch as they will each have contracted new habits, and have got into new ways, which they do not like now to alter.
We should expect that our domesticated plants and animals should vary most, inasmuch as these have been subjected to changed conditions which would disturb the memory, and, breaking the chain of recollection, through failure of some one or other of the associated ideas, would thus directly and most markedly affect the reproductive system. Every reader of Mr. Darwin will know that this is what actually happens, and also that when once a plant or animal begins to vary, it will probably vary a good deal further; which, again, is what we should expect--the disturbance of the memory introducing a fresh factor of disturbance, which has to be dealt with by the offspring as it best may. Mr. Darwin writes: "All our domesticated productions, with the rarest exceptions, vary far more than natural species" ("Plants and Animals," &c., vol ii. p. 241, ed. 1875).
On my third supposition, i.e., when the difference between parents has not been great enough to baffle reproduction on the part of the first cross, but when the histories of the father and mother have been, nevertheless, widely different--as in the case of Europeans and Indians--we should expect to have a race of offspring who should seem to be quite clear only about those points, on which their progenitors on both sides were in accord before the manifold divergencies in their experiences commenced; that is to say, the offspring should show a tendency to revert to an early savage condition.
That this indeed occurs may be seen from Mr. Darwin's "Plants and Animals under Domestication" (vol ii. p. 21, ed. 1875), where we find that travellers in all parts of the world have frequently remarked "ON THE DEGRADED STATE AND SAVAGE CONDITION OF CROSSED RACES OF MAN." A few lines lower down Mr. Darwin tells us that he was himself "struck with the fact that, in South America, men of complicated descent between Negroes, Indians, and Spaniards seldom had, whatever the cause might be, a good expression." "Livingstone" (continues Mr. Darwin) "remarks, 'It is unaccountable why half-castes are so much more cruel than the Portuguese, but such is undoubtedly the case.' An inhabitant remarked to Livingstone, 'God made white men, and God made black men, but the devil made half-castes.'" A little further on Mr. Darwin says that we may "perhaps infer that the degraded state of so many half-castes IS IN PART DUE TO REVERSION TO A PRIMITIVE AND SAVAGE CONDITION, INDUCED BY THE ACT OF CROSSING, even if mainly due to the unfavourable moral conditions under which they are generally reared." Why the crossing should produce this particular tendency would seem to be intelligible enough, if the fashion and instincts of offspring are, in any case, nothing but the memories of its past existences; but it would hardly seem to be so upon any of the theories now generally accepted; as, indeed, is very readily admitted by Mr. Darwin himself, who even, as regards purely-bred animals and plants, remarks that "we are quite unable to assign any proximate cause" for their tendency to at times reassume long lost characters.
If the reader will follow for himself the remaining phenomena of reversion, he will, I believe, find them all explicable on the theory that they are due to memory of past experiences fused, and modified-- at times specifically and definitely--by changed conditions. There is, however, one apparently very important phenomenon which I do not at this moment see how to connect with memory, namely, the tendency on the part of offspring to revert to an earlier impregnation. Mr. Darwin's "Provisional Theory of Pangenesis" seemed to afford a satisfactory explanation of this; but the connection with memory was not immediately apparent. I think it likely, however, that this difficulty will vanish on further consideration, so I will not do more than call attention to it here.
The instincts of certain neuter insects hardly bear upon reversion, but will be dealt with at some length in Chapter XII.
V. We should expect to find, as was insisted on in the preceding section in reference to the sterility of hybrids, that it required many, or at any rate several, generations of changed habits before a sufficiently deep impression could be made upon the living being (who must be regarded always as one person in his whole line of ascent or descent) for it to be unconsciously remembered by him, when making himself anew in any succeeding generation, and thus to make him modify his method of procedure during his next embryological development. Nevertheless, we should expect to find that sometimes a very deep single impression made upon a living organism, should be remembered by it, even when it is next in an embryonic condition.
That this is so, we find from Mr. Darwin, who writes ("Plants and Animals under Domestication," vol. ii. p. 57, ed. 1875)--"There is ample evidence that the effect of mutilations and of accidents, especially, or perhaps exclusively, when followed by disease" (which would certainly intensify the impression made), "are occasionally inherited. There can be no doubt that the evil effects of the long continued exposure of the parent to injurious conditions are sometimes transmitted to the offspring." As regards impressions of a less striking character, it is so universally admitted that they are not observed to be repeated in what is called the offspring, until they have been confirmed in what is called the parent, for several generations, but that after several generations, more or fewer as the case may be, they often are transmitted--that it seems unnecessary to say more upon the matter. Perhaps, however, the following passage from Mr. Darwin may be admitted as conclusive:-
"That they" (acquired actions) "are inherited, we see with horses in certain transmitted paces, such as cantering and ambling, which are not natural to them--in the pointing of young pointers, and the setting of young setters--in the peculiar manner of flight of certain breeds of the pigeon, &c. We have analogous cases with mankind in the inheritance of tricks or unusual gestures." . . . ("Expression of the Emotions," p. 29).
In another place Mr. Darwin writes:-
"How again can we explain THE INHERITED EFFECTS of the use or disuse of particular organs? The domesticated duck flies less and walks more than the wild duck, and its limb bones have become diminished and increased in a corresponding manner in comparison with those of the wild duck. A horse is trained to certain paces, and the colt inherits similar consensual movements. The domesticated rabbit becomes tame from close confinement; the dog intelligent from associating with man; the retriever is taught to fetch and carry; and these mental endowments and bodily powers are all inherited" ("Plants and Animals," &c., vol. ii. p. 367, ed. 1875).
"Nothing," he continues, "in the whole circuit of physiology is more wonderful. How can the use or disuse of a particular limb, or of the brain, affect a small aggregate of reproductive cells, seated in a distant part of the body in such a manner that the being developed from these cells inherits the character of one or both parents? Even an imperfect answer to this question would be satisfactory" ("Plants and Animals," &c. vol. ii. p. 367, ed. 1875).
With such an imperfect answer will I attempt to satisfy the reader, as to say that there appears to be that kind of continuity of existence and sameness of personality, between parents and offspring, which would lead us to expect that the impressions made upon the parent should be epitomised in the offspring, when they have been or have become important enough, through repetition in the history of several so-called existences to have earned a place in that smaller edition, which is issued from generation to generation; or, in other words, when they have been made so deeply, either at one blow or through many, that the offspring can remember them. In practice we observe this to be the case--so that the answer lies in the assertion that offspring and parent, being in one sense but the same individual, there is no great wonder that, in one sense, the first should remember what had happened to the latter; and that too, much in the same way as the individual remembers the events in the earlier history of what he calls his own lifetime, but condensed, and pruned of detail, and remembered as by one who has had a host of other matters to attend to in the interim.
It is thus easy to understand why such a rite as circumcision, though practised during many ages, should have produced little, if any, modification tending to make circumcision unnecessary. On the view here supported such modification would be more surprising than not, for unless the impression made upon the parent was of a grave character--and probably unless also aggravated by subsequent confusion of memories in the cells surrounding the part originally impressed--the parent himself would not be sufficiently impressed to prevent him from reproducing himself, as he had already done upon an infinite number of past occasions. The child, therefore, in the womb would do what the father in the womb had done before him, nor should any trace of memory concerning circumcision be expected till the eighth day after birth, when, but for the fact that the impression in this case is forgotten almost as soon as made, some slight presentiment of coming discomfort might, after a large number of generations, perhaps be looked for as a general rule. It would not, however, be surprising, that the effect of circumcision should be occasionally inherited, and it would appear as though this was sometimes actually the case.
The question should turn upon whether the disuse of an organ has arisen:-
1. From an internal desire on the part of the creature disusing it, to be quit of an organ which it finds troublesome.
2. From changed conditions and habits which render the organ no longer necessary, or which lead the creature to lay greater stress on certain other organs or modifications.
3. From the wish of others outside itself; the effect produced in this case being perhaps neither very good nor very bad for the individual, and resulting in no grave impression upon the organism as a whole.
4. From a single deep impression on a parent, affecting both himself as a whole, and gravely confusing the memories of the cells to be reproduced, or his memories in respect of those cells--according as one adopts Pangenesis and supposes a memory to "run" each gemmule, or as one supposes one memory to "run" the whole impregnate ovum--a compromise between these two views being nevertheless perhaps possible, inasmuch as the combined memories of all the cells may possibly BE the memory which "runs" the impregnate ovum, just as we ARE ourselves the combination of all our cells, each one of which is both autonomous, and also takes its share in the central government. But within the limits of this volume it is absolutely impossible for me to go into this question.
In the first case--under which some instances which belong more strictly to the fourth would sometimes, but rarely, come--the organ should soon go, and sooner or later leave no rudiment, though still perhaps to be found crossing the life of the embryo, and then disappearing.
In the second it should go more slowly, and leave, it may be, a rudimentary structure.
In the third it should show little or no sign of natural decrease for a very long time.
In the fourth there may be absolute and total sterility, or sterility in regard to the particular organ, or a scar which shall show that the memory of the wound and of each step in the process of healing has been remembered; or there may be simply such disturbance in the reproduced organ as shall show a confused recollection of injury. There may be infinite gradations between the first and last of these possibilities.
I think that the facts, as given by Mr. Darwin ("Plants and Animals," &c., vol i. pp. 466-472, ed. 1875), will bear out the above to the satisfaction of the reader. I can, however, only quote the following passage:-
" . . . Brown Sequard has bred during thirty years many thousand guinea-pigs, . . . 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 fact thirteen instances were carefully recorded, and a greater number were seen; yet Brown Sequard speaks of such cases as among 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 DIVISION till after its reunion with the peripheric end. It is not therefore the power of simply performing an action which is inherited, but the power of performing a whole series of actions in a certain order.'"
I feel inclined to say it is not merely the original wound that is remembered, but the whole process of cure which is now accordingly repeated. Brown Sequard concludes, as Mr. Darwin tells us, "that what is transmitted is the morbid state of the nervous system," due to the operation performed on the parents.
A little lower down Mr. Darwin writes that Professor Rolleston has given him two cases--"namely, of two men, one of whom had his knee, and the other his cheek, severely cut, and both had children born with exactly the same spot marked or scarred."
VI. When, however, an impression has once reached transmission point--whether it be of the nature of a sudden striking thought, which makes its mark deeply then and there, or whether it be the result of smaller impressions repeated until the nail, so to speak, has been driven home--we should expect that it should be remembered by the offspring as something which he has done all his life, and which he has therefore no longer any occasion to learn; he will act, therefore, as people say, INSTINCTIVELY. No matter how complex and difficult the process, if the parents have done it sufficiently often (that is to say, for a sufficient number of generations), the offspring will remember the fact when association wakens the memory; it will need no instruction, and--unless when it has been taught to look for it during many generations--will expect none. This may be seen in the case of the humming-bird sphinx moth, which, as Mr. Darwin writes, "shortly after its emergence from the cocoon, as shown by the bloom on its unruffled scales, may be seen poised stationary in the air with its long hair-like proboscis uncurled, and inserted into the minute orifices of flowers; AND NO ONE I BELIEVE HAS EVER SEEN this moth learning to perform its difficult task, which requires such unerring aim" ("Expression of the Emotions," p. 30).
And, indeed, when we consider that after a time the most complex and difficult actions come to be performed by man without the least effort or consciousness--that offspring cannot be considered as anything but a continuation of the parent life, whose past habits and experiences it epitomises when they have been sufficiently often repeated to produce a lasting impression--that consciousness of memory vanishes on the memory's becoming intense, as completely as the consciousness of complex and difficult movements vanishes as soon as they have been sufficiently practised--and finally, that the real presence of memory is testified rather by performance of the repeated action on recurrence of like surroundings, than by consciousness of recollecting on the part of the individual--so that not only should there be no reasonable bar to our attributing the whole range of the more complex instinctive actions, from first to last, to memory pure and simple, no matter how marvellous they may be, but rather that there is so much to compel us to do so, that we find it difficult to conceive how any other view can have been ever taken--when, I say, we consider all these facts, we should rather feel surprise that the hawk and sparrow still teach their offspring to fly, than that the humming-bird sphinx moth should need no teacher.
The phenomena, then, which we observe are exactly those which we should expect to find.
VII. We should also expect that the memory of animals, as regards their earlier existences, was solely stimulated by association. For we find, from Prof. Bain, that "actions, sensations, and states of feeling occurring together, or in close succession, tend to grow together or cohere in such a way that when any one of them is afterwards presented to the mind, the others are apt to be brought up in idea" ("The Senses and the Intellect," 2d ed. 1864, p. 332). And Prof. Huxley says ("Elementary Lessons in Physiology," 5th ed. 1872, p. 306), "It may be laid down as a rule that if any two mental states be called up together, or in succession, with due frequency and vividness, the subsequent production of the one of them will suffice to call up the other, AND THAT WHETHER WE DESIRE IT OR NOT." I would go one step further, and would say not only whether we desire it or not, but WHETHER WE ARE AWARE THAT THE IDEA HAS EVER BEFORE BEEN CALLED UP IN OUR MINDS OR NOT. I should say that I have quoted both the above passages from Mr. Darwin's "Expression of the Emotions" (p. 30, ed. 1872).
We should, therefore, expect that when the offspring found itself in the presence of objects which had called up such and such ideas for a sufficient number of generations, that is to say, "with due frequency and vividness"--it being of the same age as its parents were, and generally in like case as when the ideas were called up in the minds of the parents--the same ideas should also be called up in the minds of the offspring "WHETHER THEY DESIRE IT OR NOT;" and, I would say also, "whether they recognise the ideas as having ever before been present to them or not."
I think we might also expect that no other force, save that of association, should have power to kindle, so to speak, into the flame of action the atomic spark of memory, which we can alone suppose to be transmitted from one generation to another.
That both plants and animals do as we should expect of them in this respect is plain, not only from the performance of the most intricate and difficult actions--difficult both physically and intellectually-- at an age, and under circumstances which preclude all possibility of what we call instruction, but from the fact that deviations from the parental instinct, or rather the recurrence of a memory, unless in connection with the accustomed train of associations, is of comparatively rare occurrence; the result, commonly, of some one of the many memories about which we know no more than we do of the memory which enables a cat to find her way home after a hundred-mile journey by train, and shut up in a hamper, or, perhaps even more commonly, of abnormal treatment.
VIII. If, then, memory depends on association, we should expect two corresponding phenomena in the case of plants and animals--namely, that they should show a tendency to resume feral habits on being turned wild after several generations of domestication, and also that peculiarities should tend to show themselves at a corresponding age in the offspring and in the parents. As regards the tendency to resume feral habits, Mr. Darwin, though apparently of opinion that the tendency to do this has been much exaggerated, yet does not doubt that such a tendency exists, as shown by well authenticated instances. He writes: "It has been repeatedly asserted in the most positive manner by various authors that feral animals and plants invariably return to their primitive specific type."
This shows, at any rate, that there is a considerable opinion to this effect among observers generally.
He continues: "It is curious on what little evidence this belief rests. Many of our domesticated animals could not subsist in a wild state,"--so that there is no knowing whether they would or would not revert. "In several cases we do not know the aboriginal parent species, and cannot tell whether or not there has been any close degree of reversion." So that here, too, there is at any rate no evidence AGAINST the tendency; the conclusion, however, is that, notwithstanding the deficiency of positive evidence to warrant the general belief as to the force of the tendency, yet "the simple fact of animals and plants becoming feral does cause some tendency to revert to the primitive state," and he tells us that "when variously- coloured tame rabbits are turned out in Europe, they generally re- acquire the colouring of the wild animal;" there can be no doubt," he says, "that this really does occur," though he seems inclined to account for it by the fact that oddly-coloured and conspicuous animals would suffer much from beasts of prey and from being easily shot. "The best known case of reversion:" he continues, "and that on which the widely-spread belief in its universality apparently rests, is that of pigs. These animals have run wild in the West Indies, South America, and the Falkland Islands, and have everywhere re- acquired the dark colour, the thick bristles, and great tusks of the wild boar; and the young have re-acquired longitudinal stripes." And on page 22 of "Plants and Animals under Domestication" (vol. ii. ed. 1875) we find that "the re-appearance of coloured, longitudinal stripes on young feral pigs cannot be attributed to the direct action of external conditions. In this case, and in many others, we can only say that any change in the habits of life apparently favours a tendency, inherent or latent, in the species to return to the primitive state." On which one cannot but remark that though any change may favour such tendency, yet the return to original habits and surroundings appears to do so in a way so marked as not to be readily referable to any other cause than that of association and memory--the creature, in fact, having got into its old groove, remembers it, and takes to all its old ways.
As regards the tendency to inherit changes (whether embryonic, or during post-natal development as ordinarily observed in any species), or peculiarities of habit or form which do not partake of the nature of disease, it must be sufficient to refer the reader to Mr. Darwin's remarks upon this subject ("Plants and Animals Under Domestication," vol. ii. pp. 51-57, ed. 1875). The existence of the tendency is not likely to be denied. The instances given by Mr. Darwin are strictly to the point as regards all ordinary developmental and metamorphic changes, and even as regards transmitted acquired actions, and tricks acquired before the time when the offspring has issued from the body of the parent, or on an average of many generations does so; but it cannot for a moment be supposed that the offspring knows by inheritance anything about what happens to the parent subsequently to the offspring's being born. Hence the appearance of diseases in the offspring, at comparatively late periods in life, but at the same age as, or earlier, than in the parents, must be regarded as due to the fact that in each case the machine having been made after the same pattern (which IS due to memory), is liable to have the same weak points, and to break down after a similar amount of wear and tear; but after less wear and tear in the case of the offspring than in that of the parent, because a diseased organism is commonly a deteriorating organism, and if repeated at all closely, and without repentance and amendment of life, will be repeated for the worse. If we do not improve, we grow worse. This, at least, is what we observe daily.
Nor again can we believe, as some have fancifully imagined, that the remembrance of any occurrence of which the effect has been entirely, or almost entirely mental, should be remembered by offspring with any definiteness. The intellect of the offspring might be affected, for better or worse, by the general nature of the intellectual employment of the parent; or a great shock to a parent might destroy or weaken the intellect of the offspring; but unless a deep impression were made upon the cells of the body, and deepened by subsequent disease, we could not expect it to be remembered with any definiteness, or precision. We may talk as we will about mental pain, and mental scars, but after all, the impressions they leave are incomparably less durable than those made by an organic lesion. It is probable, therefore, that the feeling which so many have described, as though they remembered this or that in some past existence, is purely imaginary, and due rather to unconscious recognition of the fact that we certainly have lived before, than to any actual occurrence corresponding to the supposed recollection.
And lastly, we should look to find in the action of memory, as between one generation and another, a reflection of the many anomalies and exceptions to ordinary rules which we observe in memory, so far as we can watch its action in what we call our own single lives, and the single lives of others. We should expect that reversion should be frequently capricious--that is to say, give us more trouble to account for than we are either able or willing to take. And assuredly we find it so in fact. Mr. Darwin--from whom it is impossible to quote too much or too fully, inasmuch as no one else can furnish such a store of facts, so well arranged, and so above all suspicion of either carelessness or want of candour--so that, however we may differ from him, it is he himself who shows us how to do so, and whose pupils we all are--Mr. Darwin writes: "In every living being we may rest assured that a host of long-lost characters lie ready to be evolved under proper conditions" (does not one almost long to substitute the word "memories" for the word "characters?") "How can we make intelligible, and connect with other facts, this wonderful and common capacity of reversion--this power of calling back to life long-lost characters?" ("Plants and Animals," &c., vol. ii. p. 369, ed. 1875). Surely the answer may be hazarded, that we shall be able to do so when we can make intelligible the power of calling back to life long-lost memories. But I grant that this answer holds out no immediate prospect of a clear understanding.
One word more. Abundant facts are to be found which point inevitably, as will appear more plainly in the following chapter, in the direction of thinking that offspring inherits the memories of its parents; but I know of no single fact which suggests that parents are in the smallest degree affected (other than sympathetically) by the memories of their offspring AFTER THAT OFFSPRING HAS BEEN BORN. Whether the unborn offspring affects the memory of the mother in some particulars, and whether we have here the explanation of occasional reversion to a previous impregnation, is a matter on which I should hardly like to express an opinion now. Nor, again, can I find a single fact which seems to indicate any memory of the parental life on the part of offspring later than the average date of the offspring's quitting the body of the parent.