There are also a number of actions which constantly recur in ourselves, which more or less nearly approximate to reflex action. Thus the respiratory movements, the various muscular motions by the aid of which we breathe, are ordinarily performed by us without advertence, though we can, if we will, perform them with self-conscious deliberation. It is well also to note that when our mind is entirely directed upon some external object, or when we are almost in a state of somnolent unconsciousness, we have but a vague feeling of our existence—a feeling resulting from the unobserved synthesis of our sensations of all orders and degrees. This unintellectual sense of “self” may be conveniently distinguished from intellectual consciousness as “consentience.” We may also, as everybody knows, suddenly recollect sights or sounds which were quite unnoticed at the time we experienced them; yet our very recollection of them proves that they must, nevertheless, have affected our sensorium. Such unnoticed modifications of our sense organs may also be provisionally included in the category of those actions of the lower animals, before provisionally denominated “unfelt sensations.” It is not, however, with such inferior activities as reflex and other insentient actions that instinct is commonly contrasted, but with “reason.” Now “reasonable,” “consciously intelligent”conduct is understood by all men to mean conduct in which there is a more or less wise adaptation of means to ends—a conscious, deliberate adaptation, not one due to accident only. No one would call an act done blindly a reasonable or intelligent action on the part of him who did it, however fortunate might be its result. Instinctive actions, then, hold a middle place between (1) those which are rational, or truly intelligent, and (2) those in which sensation has no place. But a great variety of actions of different kinds occupy this intermediate position, and we must next proceed to separate off from the others, such actions as may be deemed truly instinctive.
M. Albert Lemoine, who has written the best treatise[3] known to us on instinct and habit, distinguishes instinctive actions as those which are neither due to mechanical or chemical causes, nor to intelligence, experience, or will. They are actions which take place with a general fixity and precision, are generally present in all the individuals of each species, and can be perfectly performed the very first time their action is called for, so that they cannot be due to habit. Instinct, he very truly says, is more than a want and less than a desire. Instinct is a certain felt internal stimulus to definite actions which has its foundation in a certain sense of want, but is not definite feeling of want of the particular end to be attained. Were that recognised, it would not be instinct, but desire. It is but a vague craving to exercise certain activities the exercise of which conduces to useful or needful, but unforeseen, end. Instinct often sets in motion organs quite different from those which feel the prick of want, and which do not (experience apart) seem to have relation with it. Hunger does not stimulate to action the organs of digestion which suffer from it, but excites the limbs and jaws to perform acts by which food may be obtained and eaten. In examining into instinct, we must be careful not to omit the consideration of it as it exists in man, since we can know no creature so well as we can, by the help of language and reflection, know ourselves and our own species. Nevertheless, it may be well to begin by calling attention to certain apparently undeniable cases of instinct in other animals, since in them instinct is much more apparent and complex than in man, in whom it is indeed reduced to a minimum. It might naturally be expected to be so reduced in him—if it is a power serving to bridge over the gulf which exists between such almost mechanical action as reflex action, and true intelligence—since in man acts of intelligence, or habits originated through intelligence, come so constantly into play. But before enumerating cases of animal instinct, a word should be said as to one character which M. Lemoine attributes to instinctive action, namely, “consciousness,” This term is an exceedingly ambiguous one, as it is often referred, not only to our distinct intellectual perception of our own being and acts, but also to every state of feeling however rudimentary it may be. I would therefore avoid the use of so equivocal a term, while fully admitting that no sensation in any animal is possible without some subjective psychical state analogous to what I have before denominated “consentience.” Now, as to the lower animals: birds unquestionably possess instinctive powers. Chickens, two minutes after they have left the egg,[4] will follow with their eyes the movements of crawling insects, and peck at them, judging distance and direction with almost infallible accuracy. They will instinctively appreciate sounds, readily running towards an invisible hen hidden in a box, when they hear her “call.” Some young birds, also, have an innate, instinctive horror of the sight of a hawk and of the sound of its voice. Swallows, titmice, tomtits, and wrens, after having been confined from birth, are capable of flying successfully at once, when liberated, on their wings having attained the necessary growth to render flight possible. The Duke of Argyll[5] relates some very interesting particulars about the instincts of birds, especially of the water ousel, the merganser, and the wild duck. Even as to the class of beasts I find recorded:[6] “Five young polecats were found comfortably embedded in dry withered grass; and in a side hole, of proper dimensions for such a larder, were forty frogs and two toads, all alive, but merely capable of sprawling a little. On examination the whole number, toads and all, proved to have been purposely and dexterously bitten through the brain.” Evidently the parent polecat had thus provided the young with food which could be kept perfectly fresh, because alive, and yet was rendered quite unable to escape. This singular instinct is like others which are yet more fully developed amongst insects—a class of animals the instincts of which are so numerous, wonderful, and notorious that it will be, probably, enough to refer to one or two examples. The female carpenter bee, in order to protect her eggs, excavates, in some piece of wood, a series of chambers, in special order with a view to a peculiar mode of exit for her young: but the young mother can have no conscious knowledge of the series of actions subsequently to ensue. The female of the wasp, sphex, affords another well-known but very remarkable example of a complex instinct closely related to that already mentioned in the case of the polecat. The female wasp has to provide fresh, living animal food for her progeny, which, when it quits its egg, quits it in the form of an almost helpless grub, utterly unable to catch, retain, or kill an active, struggling prey. Accordingly the mother insect has only to provide and place beside her eggs suitable living prey, but so to treat it that it may be a helpless, unresisting victim. That victim may be a mere caterpillar, or it may be a great, powerful grasshopper, or even that most fierce, active, and rapacious of insect tyrants, a fell and venomous spider. Whichever it may be, the wasp adroitly stings it at the spot which induces, or in the several spots which induce, complete paralysis as to motion, let us hope as to sensation also. This done, the wasp entombs the helpless being with its own egg, and leaves it for the support of the future grub. Another species feeds her young one from time to time with fresh food, visiting at suitable intervals the nest she has made and carefully covered and concealed with earth, which she removes and replaces, as far as necessary, at each visit. If the opening be made ready for her, this, instead of helping her to get at her young, altogether puzzles her, and she no longer seems to recognise her young, thus showing how thoroughly “instinctive” her proceedings are. Other instances of instinct, such as those of the stag-beetle and emperor moth, I will refer to presently. But most wonderful, perhaps, of all are the instincts of social insects, such as bees, where there are not only males and females, but a large population of practically neuter insects, the special instincts and peculiarities of which have of course to be transmitted, not directly by an antecedent set of neuter animals, but by females, the instincts and peculiarities of which are very different from those of the neutral portion of their progeny.
The instincts we have hitherto noticed, and, I may say briefly, the instincts of animals generally, are destined to subserve two functions, (1) the preservation and, mainly, the nutrition, of the individual, and (2) the reproduction of the species. Armed with the facts we have now noticed, let us turn to consider instinct as it displays itself in ourselves. As one example, there is the instinct action by which an infant first sucks the nipple, and then swallows the thence-extracted nourishment with which its mouth is filled. This action must be reckoned as instinctive, because it is done directly after birth, when there has been no time for learning to perform the action; it is one absolutely necessary for the life of the infant; it is an action which is definite and precise, similarly performed by all the individuals of the species, though effected by a very complex mechanism, and is effected prior to experience. Yet it is not as mechanical as reflex action, for not only sensation, but consentience, accompanies the act. Thus sucking in man is an instinctive action, while spitting, on the other hand, is an art. The latter is not necessary to life, and the power of performing it is slowly acquired by experience, as are also our powers of walking and feeding ourselves. But the action of sucking in an adult human being is of course not instinctive; and because the child learns to walk, it by no means follows that the insect learns to fly. It is thus plain that actions may be instinctive in one animal and not in another; or at one period of life in the same animal and not at another. In a child, however, sucking, deglutition, inspiration, and expiration are instinctive actions, as are also those by which the products of excretion are removed from the body. The second class of instincts, those which ensure the continuance of the race, show themselves of course, only much later. Yet, long before the little girl can represent to herself future tributes to her charms, she seeks to decorate her tiny body with the arts of infant coquetry. Still less does she look forward to the pains and pleasures of maternity when she begins to caress and chastise, to soothe and cherish, her first doll, and fondly presses it to that region whence her future offspring will draw its nourishment. Again, when the lapse of a few years having made her a young woman and the boy a youth, they first feel the influence of love, however ignorant they may be of the physiology of their race, they will none the less, circumstances permitting, be surely impelled towards the performance of very definite actions. In the more refined individuals of the highest races of mankind, the material, merely animal, consummation of sexual love is most certainly far from being the one great end distinctly looked forward to by each pair of lovers. Yet every incident of affectionate intercourse, every tender glance, every contact of hand or lip, infallibly leads on towards the one useful end, indispensable to the race, which nature has in view. Such actions fully merit to be called “instinctive.” Indeed the act of generation is ministered to in nature by the most manifold, imperious, general, and inexplicable of all the instincts, and its instinctive character is the most strongly marked of all. It has emphatically for its origin a rigorously determined and precise want, partly painful, partly pleasurable—a mixture of a feeling of privation with a sense of power. Its end is unknown to the agent, or if known is disregarded, and in almost all animals it demands the concurrent and reciprocal action of two diverse organisms. If anyone would deny that it is instinctive in man, I would advise him to study the sad phenomena connected therewith which may be observed in our asylums for the insane.
There are other human actions which are sometimes reckoned as instinctive, such as guarding the eye against injury by suddenly closing the eyelids. This action, however, appears to be an acquired art, though the habitual act of winking to keep clean the surface of the eye may be instinctive. Some other actions, however, not generally regarded as instinctive, I should be disposed so to regard. Such are the first active exercises of the senses of seeing, hearing, smelling, tasting, and feeling (the first “looking,” the first “listening,” etc.) which the child performs at the very beginning of its learning to perform them. It would seem, then, as if no one could deny the existence of such a thing as instinct, and yet it has been denied, not only in recent times, but centuries ago. Thus Montaigne sought to explain instinct as but a form of intelligence, while Descartes taught that it was but mechanism. Condillac regarded it as the result of individual experience, and Lemarck considered it to be merely “habit” which had become hereditary. In our own day Darwin has sought to explain it as partly the result of accidental variations of activity, which variations have become naturally selected, and partly the result of intelligent, purposive action which has become habitual and inherited. Let us consider these attempts at explanation seriatim. First as to mechanism: This is an hypothesis no one at present entertains, as everyone now credits animals with sensitivity. Moreover, instincts are not absolutely invariable, but are modifiable according to the degree of “intelligence” which animals possess. They cannot, therefore, be due merely to a mechanism. The attempt to explain “Instinct” by mere “reflex action” is equivalent to an attempt to explain a phenomenon by omitting its most striking characteristic. In “reflex action” we have a sudden response to a stimulus, which response is more or less purposive as regards the time of its occurrence, but has no reference to future events to occur long after the faintest waves of the stimulating action have died out. The very essence of “instinct,” however, is to provide for a more or less distant future, often, as we have seen, the future of another generation. It is essentially telic, and directed to a future unforeseen, but generally useful, end. This explanation, then, is fundamentally and necessarily inadequate. It is like an explanation of the building of a house, by “bricks, mortar, bricklayers, and hodmen,” with the omission of all reference to any influence governing their motions and directing them towards a common and predetermined end which is not theirs. But though we cannot explain “instinct” by “reflex action,” there is none the less a certain obvious affinity between these two forms of animal activity, and it is in part my object to point out the nature of this very affinity.
Next we may pass in review the two hypotheses that instinct is but (1) a form of intelligence, or (2) individual experience. As to the first, I have already given instances of unquestionably instinctive actions performed by birds as soon as they quit the eggshell, and it would be but waste of time to argue against the view that the human infant is guided by intelligent purpose and conscious foresight in his very first acts of sucking, swallowing, and defecation. Actual intelligence, therefore, is a radically insufficient explanation, as also, for the very same reasons, is Condillac’s hypothesis as to individual experience. About “lapsed intelligence” I will speak later on. Lemarck’s hypothesis, that instinct is but inherited habit, is one which is much more worthy of careful consideration than any we have yet considered. For it may be admitted at once that habits may be inherited. There are many instances of such inheritance in human beings, and as regards the lower animals, the barking of dogs may be taken as an instance of a habit thus perpetuated. In fact “habit,” when inherited, so simulates instinct, that their confusion is far from surprising. There is, however, this radical difference between them: “habit” enables an agent to repeat with facility and precision an act which has been done before, but “instinct” determines with precision the first performance of such act. Referring instinct to habit, but temporarily relieves the difficulty of those who object to instinct, by putting it a step back. It is impossible to believe that any of the progenitors of an infant of to-day first acquired, during his or her lifetime, the habit of sucking, or that the habits of neuter insects thus arose. But after all, if we could explain “instinct” by “habit,” should we thereby make the phenomena less mysterious? “Habit” is due to an internal spontaneity of living things. A living thing no doubt requires some internal solicitation, in order that it should move, but when it does move that movement is its own. All living organisms tend to act. With them action is not only their nature, ’tis a want; and, within limits, their powers and energies increase with action, and diminish and finally perish through repose. The power of generating any “habits,” lies in the very first act of the kind an organism performs, and it is only the first act which owes nothing to habit. If such were not the case, an act might be performed a thousand times and yet not generate habit. It is this mysterious internal active tendency which distinguishes all living organisms from inorganic bodies. The latter tend simply to persist as they are, and have no relations with the past or the future. They have, therefore, no relations with time at all—for the actual present ever evades us. Organisms, on the other hand, which are permanently more or less changed, through habit, by every new motion and sensation, have their future prepared by their past, and thus, as it were, at every present moment they live both in the past and in the future, a mode of existence which attains its fullest development in the highest living organism—man, the creature looking before and after! Thus those who would do away with mystery in nature would gain little by explaining instinct through habit, though, as we have seen, the phenomena presented to us by the human infant and by neuter insects absolutely bar any such explanation. Moreover, the attempt to explain “instinct” through “inheritance” is a contradiction, since “inheritance” supposes something already obtained, otherwise it could not be transmitted. So far, then, from “hereditary transmission” explaining “instinct,” instinct, in whatever remote ancestor it first arose, must have been a violation of the law of hereditary transmission.
Now as to “lapsed intelligence:” This hypothesis assumes that a conscious deliberate, discriminating faculty must have once been exercised by wasps, bees, ants, and other much more lowly animals, in the performance of all those actions which are now instinctive. But could the adult female insect be supposed to foresee the future needs of her progeny, often so totally different from her own wants? It would surely be too much to ask us to believe that she could distinctly recollect all her past experience as a chrysalis and as a grub from the moment she first quitted the egg. Can we suppose that the generative acts of male insects, such as bees, could have been due to deliberate and rational choice, when every such act is necessarily fatal to him who performs it?
Nevertheless, persuaded as I am that “lapsed intelligence” will not explain “instinct” generally, I should be the last to deny that certain apparently instinctive actions may be so explained, and I fully admit that intelligent action in ourselves does tend to become practically though not really instinctive. It is, moreover, very fortunate for us that such is the case, as thereby we are saved great mental friction. Our intellect has first to be laboriously applied to learn what afterwards becomes almost automatic, as the actions of reading, writing, etc. Sensations and bodily actions having been duly kneaded together, the intellect becomes free to withdraw and apply itself to other work—fresh conquests of mere animality—leaving the organism to carry on automatically the new faculties thus acquired. Were it not for this power which we have of withdrawing our attention, our intellect would be absorbed and wasted in the merest routine work, instead of being set free to appropriate and render practically instinctive, a continually wider and more important range of deliberate purposive actions. We come now to the sixth and last attempt to explain instinct, namely, Mr. Darwin’s attempt. He has recognised the futility of seeking to explain many instinctive actions in any of the modes we have yet considered, and he has proposed, as before said, to explain such residual instinctive phenomena by the play of natural selection, i.e. of the destructive forces of nature upon small, accidental abnormalities of action on the part of individuals of a species; such abnormalities, when favorable to the existence of the individual, being preserved and perpetuated by the destruction of the other individuals of the same species who adhered to their ancestral tendencies. But this proposed explanation is not an explanation of the origin of instincts, but only of the changes and transformations of instincts already acquired. But putting back the date or modifying the form of the original instinct, in no way alters the essential nature of instincts or diminishes its mystery. Let us look at one or two strong cases of instinct, and see if it is credible that they should be due to mere accidental, haphazard, minute changes in habits already acquired. In the first place, there is the wonderful instinct of the duck, which feigns to have an injured wing, in order to entice a dog away from the pursuit of her ducklings. Is it conceivable that such an act was first done by pure accident, and that the descendants of her who so acted, having inherited the tendency, have been alone selected and preserved? Again, there is the case of the wasp, sphex, which stings spiders, caterpillars, and grasshoppers exactly in the spot, or spots, where their nervous ganglia lie, and so paralyses them. Even the strongest advocate of the intelligence of insects would not affirm that the mother sphex has a knowledge of the comparative anatomy of the nervous system of these very diversely formed insects. According to the doctrine of natural selection, either an ancestral wasp must have accidentally stung them each in the right places, and so our sphex of to-day is the naturally selected descendant of a line of insects which inherited this lucky tendency to sting different insects differently, but always in the exact situation of their nervous ganglia; or else the young of the ancestral sphex originally fed on dead food, but the offspring of some individuals who happened to sting their prey so as to paralyse but not kill them, were better nourished and so the habit grew. But the incredible supposition that the ancestor should accidentally have acquired the habit of stinging different insects differently, but always in the right spot, is not eliminated by the latter hypothesis.
There is, again, the case of neuter insects and the highly complex instincts of insects living in communities, such as bees, ants, and termites. The Darwinian theory has the great advantage of only needing for its support the suggestion of some possible utility in each case; and as all structures and functions in nature have their utility, the task is not a difficult one for an ingenious, patient, and accomplished thinker. Yet Mr. Darwin, with all his ingenuity, patience, and accomplishments, has been unable to suggest a rational explanation for the accidental origin of these insect communities with their marvellously complex instincts. I will confine myself to one more instance of a highly noteworthy instinct, which no one has in any way succeeded in explaining. The instance I refer to is that by which an animal, when an enemy approaches, lies quite quiescent and apparently helpless, an action often spoken of as “shamming death.” To evade the force of this remarkable case of instinct, it has been objected that the disposition of the limbs adopted by insects which thus act, is not the same as that which the limbs assume when such insects are really dead, and that all species are not when thus acting equally quiescent. The first observation, however, does not concern the matter really at issue. The remarkable thing is not that a helpless insect should assume the position of its own dead, but that such a creature, instead of trying to escape, should adopt a mode of procedure utterly hopeless unless the enemy’s attention is thereby effectually eluded. It is impossible that this instinct could have been gradually gained by the elimination of all those individuals who did not practice it, for if the quiescence, whether absolutely complete or not, were not sufficient at once to make the creature elude observation, its destruction would be only the more fully insured by such ineffectual quiescence. The same argument applies to birds which seem to feign lameness or other injury. Yet even if we could account for these cases, which as a fact are as yet entirely unaccounted for, it would not do away with the need of recognising the real existence and peculiar nature of instinct. It would not do so on account both of man’s highest and of man’s lowest instinctive powers. To speak first of the former: as instinct, such as we have hitherto discovered, is the appointed bridge between mere organic and intellectual animal life, so there is in man a further development of instinct, peculiar to him, and serving to bridge over the gulf between mere intelligent animal faculty and distinctly human reflective intellectual activity. Such special intellectual instinct is that which impels man to the external manifestation by voice or gesture of the mental abstractions which his intellect spontaneously forms, and which are not formed by the lower animals, which give no evidence of this power of abstraction. Language could never have been deliberately invented nor have arisen by a mere accidental individual variation, for vocal and gesture signs are essentially conventional, and require more or less comprehension on the part of those to whom they are addressed as well as on the part of those who use them. Analogous considerations apply to the first beginnings of what cannot be reckoned as merely instinctive activities, but the origins of which must have been akin to instincts. I refer to the beginnings of literature, art, science and politics, which were never deliberately invented. Even men who supposed they were inventing and constructing a certain new order of things with full purpose and much intelligence, have really been all the time so dominated by influences beyond their consciousness, that they really evolved something very different from what they supposed or intended. This fact has been most instructively shown by De Tocqueville and Taine with respect to the men who promoted and carried through the great French Revolution. So much, then, for man’s highest instinctive powers: but our argument has no need to refer to them, for a consideration of man’s lowest instinctive powers alone suffices to show that they cannot be due to “natural selection,” even when aided by “lapsed intelligence.” Can it be for a moment seriously maintained that such actions of the infant as those of the sucking, deglutition, and defecation, or the sexual instincts of later life, ever arose through the accidental conservation of haphazard variations of habit in ancestral animals? If it cannot be maintained, as I am confident it cannot, then it is absolutely impossible successfully to evade the difficulty of the existence of instinct. However far we may put back the beginnings of instinct, the question as to its origin (with its subsequent modifications) ever returns, and indeed with increased importunity. How did the first sentient creatures obtain and swallow their food? How did they first come to fecundate their ova or suitably to deposit them? How did they first effect such movements as might be necessary for their respiratory processes? Wherever such phenomena first manifested themselves in sentient organisms, we are compelled therein to recognise the manifest presence of instinct—the appointed means (as before said) of bridging over the interval between the purely vegetative functions and the intelligent activities of sentient animal life. “Natural selection” is manifestly impotent to account for the existence of such a faculty as that of “instinct.” We have already seen that the hypothesis of “lapsed intelligence” is also impotent to account for it. Thus the most recently attempted explanation falls altogether to the ground. Nevertheless the theory of evolution renders it necessary to assume that as new species of animals were from time to time evolved, so also were new and appropriate instincts. How then are we to account for the origin of such new instincts? That a certain mystery attends such origin cannot be denied, but a parallel mystery attends all other kinds of vital phenomena. What can be more mysterious than the purely organic functions of animals? Though not truly instinctive, they are full of unconscious purpose, and so are akin to instinct. Our nutrition is a process of self-generation by which the various bodies which constitute our food become transformed into our own substance. This process is effected by what is called assimilation, by which process the ultimate substance, or parenchyma, of our own body and of the bodies transforms part of what is immediately external to it, into the parenchyma itself. Again, the process of secretion is, as it were, parallel to the process of alimentation or nutrition. In secretion, the body extracts from the blood new substances (the secretions) which do not exist as such within it. In nutrition, the body extracts from the blood new substances (the various tissues) which do not exist as such within it. The blood is not the only source of our nutrition, since it has the power of replenishing itself. Thus the living particles which form the ultimate substance of our body exercise a certain power of choice with respect to the contents of the fluids which come in contact with them. Such particles are not passive bodies; they are active living agents, and their action no one has yet really explained. Here, then, are a set of activities which, if duly pondered over, will be found to be fully as mysterious and inexplicable in their unconscious teleology as any phenomena of instinct as ordinarily understood. But there is another class of organic vital actions which also seem to have a decided affinity both to reflex action and to instinct, though they are not to be regarded as actual instances of either of these faculties. The actions I refer to are those which bring about the repair of injuries and the reproduction of lost parts. They are like reflex action inasmuch as they take place in perfect unconsciousness and without the will having any power over them. They are like instinct inasmuch as they are directed towards a useful and unforeseen end. In the process of healing and repair of a wounded part of the body, a fluid, perfectly structureless substance, is secreted, or poured forth, from the parts about the wound. In this substance, cells arise and become abundant; so that the substance, at first structureless, becomes what is called cellular tissue. Then, by degrees, this structure transforms itself into vessels, tendons, nerves, bone, and membrane—into some or all of such parts—according to the circumstances of the case. In a case of broken bone, the two broken ends of the bone soften, the sharp edges thus disappearing. Then a soft substance is secreted, and this becomes at first gelatinous, often afterwards cartilaginous, and, finally, osseous or bony. But not only do these different kinds of substance—these distinct tissues—thus arise and develop themselves in this neutral or, as it is called, “undifferentiated” substance, but very complex structures, appropriately formed and nicely adjusted for the performance of complex functions, may also be developed. We see this in the production of admirably formed joints in parts which were at first devoid of anything of the kind. I may quote, as an example, the case of a railway guard, whose arm had been so injured that he had been compelled to have the elbow with its joint cut out, but who afterwards developed a new joint almost as good as the old one. In the uninjured condition the outer bone of the lower arm—the radius—ends above in a smooth-surfaced cup, which plays against part of the lower end of the bone of the upper arm, or humerus, while its side also plays against the side of the other bone of the lower arm, the ulna, with the interposition of a cartilaginous surface. The radius and ulna are united to the humerus by dense and strong membranes or ligaments, which pass between it and them, anteriorly, posteriorly, and on each side, and are attached to projecting processes, one on each side of the humerus. Such was the condition of the parts which were removed by the surgeon. Nine years after the operation the patient died, and Mr. Syme had the opportunity of dissecting the arm, which in the meantime had served the poor man perfectly well, he having been in the habit of swinging himself by it from one carriage to another, while the train was in motion, quite as easily and securely as with the other arm. On examination, Mr. Syme found that the amputated end of the radius had formed a fresh polished surface, and played both on the humerus and the ulna, a material something like cartilage being interposed. The ends of the bones of the forearm were locked in by two processes projecting downwards from the humerus, and also strong lateral and still stronger anterior and posterior ligaments again bound them fast to the last-named bone.[7] It would be easy to bring forward a number of more or less similar cases. The amount of reproduction of lost parts which may take place in many of the lower animals is astonishing. Thus the tails of lizards, if broken off, will grow again, and the limbs of newts will be reproduced, with their bones, muscles, blood-vessels, and nerves. Even the eye and the lower jaw have been seen to be reproduced in the last-named animals. If certain worms be cut in two, each half will become a perfect animal, the head producing a new tail, and the tail a new head; and a worm called a nais has been cut into as many as twenty-five parts with a like result. But the most remarkable animal for its power of repairing injuries is the fresh-water hydra, almost any fragment of which will, under favorable circumstances, grow into a new and entire fresh animal. It is also a notorious and very noteworthy fact that, in both man and the lower animals, the processes of repair take place the more readily the younger the age of the injured individual may be. But these unconscious but practically teleological processes of repair, are often preceded by actions which everyone would call instinctive.
There is yet another class of organic vital actions to which I must advert, which are at once utterly unconscious, while the fact that they are directed to a distinct end is indisputable; in fact they are purposive in the very highest degree that any unconscious actions can be purposive. They are the actions of true reproduction, and they come before us naturally here, since a consideration of the process of remedial reproduction in the individual, naturally leads us on to the consideration of the reproduction of the species itself. In the cases of the frog and the butterfly, everyone knows that the creature which comes forth from the egg is very different from the parent. Animals, in fact, mostly attain their adult condition by passing through a series of development changes; only as a rule that series is not abruptly interrupted by plainly marked pauses, as it is in the frog and butterfly, and, therefore, such changes, instead of being obvious, are only to be detected with difficulty and through patient research. Almost every animal thus goes through a series of very remarkable changes during its individual process of development or, as it is called, during its “ontogeny.” This process, in its perfect unconsciousness, is like reflex action, but it is far more wonderful, since in the earliest stages even nerve-tissue is absent and has itself to be formed. In the accuracy of its direction towards a useful end, it is the very counterpart of the most developed instinct; nor, if the impulses by which adult individuals are led to seek and to perform those processes which give rise to the embryo, are to be called instinctive, is it easy to see how the analogical use of the term “instinctive” can be refused to that impulse by which each developing embryo is led to go through those processes which give rise to the adult. The action of each organism during its individual development may be compared, and has evidently much affinity with, the processes of nutrition and the repair and reproduction of parts lost through some injury. These processes of nutrition and repair have also evidently a close relation to reflex action and reflex action has also a close affinity to instinctive action. Instead, however, of explaining “instinct” by “reflex action,” I would rather explain reflex action, processes of nutrition, processes of repair, processes of individual development, by instinct—using this term in a wide analogical sense. For we know the wonderful action and nature of instinct as it exists in our own human activity, standing, as it were, at the head of the various unconsciously intelligent vital processes. These processes seem to me to be all diverse manifestations of what is fundamentally one kind of activity. Of these manifestations, instinctive action is the best type, because by it we can, to a certain extent, understand the others, whereas none of the others enable us to understand instinct.—Fortnightly Review.