CHAPTER X
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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 pœnitentiæ_ 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 _primâ 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