In insects, for instance in moths and butterflies, and no doubt in most if not all others, the sense of smell is astonishingly keen, and serves as the great guide and attraction in courtship and the appeasement of mate-hunger. A single female emperor moth was placed in a box covered with fine net in a room with an open window in a country house. In three hours a dozen males of this species had entered the room, but no other moths. In twenty-four hours there were over a hundred, all fluttering around the net-covered box in which was the female. In this and other similar experiments it was found that the odour of the female moth, though imperceptible to man, clung to the box after she was removed, and that, for some days following, the empty box was nearly as powerful an attraction to the males as when it contained the female. The antennæ which carry the olfactory sense-organs are far larger in the males than in the females, as is also the case in many other lower animals where smell is a guide to mating. A single female of the vapourer moth, which is common in the London squares and parks, has been found to attract when placed in a box in an open window in Gower Street a number of males from the neighbouring plantations; and such is the penetrating and powerful character of these odorous substances produced by female moths that in one species, in which the female is wingless and lives under water, the odour escapes through the water and attracts the males in quantities to its surface. The females then arise from the depths, and, like mermaids or the witch of the Rhine, draw the infatuated males beneath the water to love and death. In several butterflies it has been shown that the males produce sweet perfumes on the surface of the wings, which can be detected as such by man, and act as stimulants to the mate-hunger of the female butterflies, which follow the scented male in numbers. The sense of smell is thus seen to be a much more powerful guide in insects than might be supposed, and it is of equally great importance to them in other enterprises and activities of life besides those of courtship. It has also a leading importance in all the lower and lowermost animals, and is the ultimate guide (for smell and taste are not separable in such simple forms) of the motile spermatic filament in its journey to the egg cell.
I have in the course of these notes on "Courtship" more than once stated that though man shares in common with all other animals the ultimate impulse to "courtship," namely, "mate-hunger," yet that it would be a mistake to suppose that he has mechanically inherited from animal ancestors (as they do) those methods of attracting and endeavouring to fascinate the female, such as the use of gay costume, dancing and posing, beautiful singing, sweet perfume, and gentle caresses, which, at various phases of his development, he has practised. True, these methods are also practised by a variety of animals, but not by man's immediate ape-like ancestors. None of these means of courtship are inherited instincts or structures in man as they are in animals. All have been arrived at and devised by man afresh, as the result of "taking thought." And in the latest advance of civilization some of them have been to a large extent either discarded or, curiously enough, handed over to the female sex. It is the woman now who endeavours to captivate the man by a display of brave colours, clothes, plumes, and jewellery, and by exquisite dancing and gesture. Not so long ago both sexes of man practised such display, but in earliest times only the male, the woman being allowed to sport a discarded rag or a broken old necklace if she were very satisfactory and submissive in her general conduct!
I must endeavour very briefly to explain how this contrast of "instinct" with "thought, knowledge, reason, and will" must (as it seems to me) be regarded. There are three great steps in the gradual evolution of the mind. The first is the slow formation (by variation and survival of the fittest) of transmissible, and therefore inherited, mechanisms of the mind, which are of various degrees of complexity, and characterize different species and kinds of animals. These mechanisms act automatically like those of a "penny-in-the-slot machine," and are just as regularly present, and as much alike in all individuals of a species, as are the other inherited structures, such as bones, flesh, viscera, the skin and its coloured clothing of decorative feathers or hair.
Later, and added to these inherited mechanisms—often interfering with them and putting an end to them—are the mechanisms of the second step. These are mechanisms arising from individual experience; they depend on memory—the inscription on "the tablets of the mind," of the experience that this follows that. They control movement and action, usurping the privilege of the previously omnipotent inherited mechanisms or instincts. This second step in the development of mind requires an excessive quantity of brain-cells. It only makes its appearance at all in animals with large brains, and reaches a far greater development in man even than in the apes, his brain being from twice to three times the size of that of the largest living ape. This use of memory and individual experience—instead of an inherited mechanism, which is the same in every member of the species—is obviously a great advantage in the struggle for existence. There are traces of it in some of the cuttlefish and insects, but even in the fishes and reptiles among living vertebrates it is of small account, and the small brain carries on its work by good, sound, inherited mechanisms or instincts, but learns nothing, comprehends nothing! In the birds we see a little—a very little—more capacity for "learning by individual experience," and it is only in the larger and later mammals that educability, or the power of learning by individual experience, becomes of serious importance. All the larger living mammals—horse, cattle, sheep, rhinoceros, tapir—have acquired an enormous increase in the size of their brains—as much as six or eight times the volume of that of their extinct ancestors whose bones and brain cavities we find fossilized in the Tertiary strata. Man has by far the biggest brain of all these animals, and has a unique degree of educability, together with the fewest instincts or in-born hereditary mechanisms among animals. He has practically to learn by individual experience—and therefore in the form best suited to his individual requirements—a host of most important actions and behaviours which even monkeys as well as dogs and sheep and horses never have to "learn," but proceed to put in practice as soon as they are born, or, at any rate, without any preliminary process of experiment and effort. Man is the one highly "educable" animal. In consequence of his large brain and its roomy memory he can be, and is—even when a "savage"—educated. Monkeys and dogs have only small "educability" as compared with man, though more than have reptiles or fishes. Man's mind is, therefore, in this essential feature different from that of animals. The modern mammals with brains as much as eight times the bulk of their early Tertiary ancestors have, it is true, acquired "educability" and the power of storing individual experience as "memory," but their memory is far less extensive than that of man, and though its guidance is of great value to them it acts entirely, or nearly so, without consciousness. No doubt man's brain includes some hereditary mechanisms, but in the main it distinctively consists of nerve-mechanisms, formed by his own individual education, acting on receptive and specially educable brain matter. And the brain mechanism formed by education is of greater life-saving value than is that of the inherited instincts which meet general emergencies, but not those new and special to the individual.
The third step in the development of mind is the arrival (for one can call it by no other term) of that condition which we call "consciousness"—the power of saying to oneself "I am I," and of looking on as a detached existence not only at other existences but at one's own mental processes, feelings, and movements. With it comes thought, knowledge, reason, and will. We may speak of consciousness as invading or spreading gradually over the territory of mind. All the three steps of the growth of mind which I have distinguished can be seen following one on the other in the growth of a human child from infancy to adolescence. The second step—the development of individual mechanisms due to memory—is not in most animals, and not entirely in man, pervaded by or "within the area of" consciousness. Memory is at first "unconscious memory," and there still remains in man a capacity for forming "memory" which never (or in some matters only exceptionally) becomes illuminated by consciousness. Apparently the inherited mechanisms which we call "instincts" are never within the reach of consciousness, though, of course, the actions determined by them are. It is a difficult matter to decide how far the memory of apes, dogs, and such animals nearest to man is conscious memory. Probably very little. But it is only when memory, as well as the impression of the moment, is pervaded by consciousness that reflection, and reason and action dependent on reason, are possible.[6]
[6] I have alluded to this subject again, necessarily with some repetition in the chapter on "The Mind of Apes and of Man," p. 262.
Hence it is that man in all the procedure of courtship stands apart from animals. Even the Australian has not only an educable brain, but a more or less conscious memory. He seems to be permanently, in this respect, in the condition of an ordinary European child of about five years old. Gradually in the course of the development, both of increased educability and of more and more efficient and serviceable education, man has first abandoned by slow degrees his violent ancestral methods of procuring a mate, and has, as the result of observation, reflection, and conscious reasoning, taken to courtship by persuasion and fascination, similar to that of the birds and other remote creatures, retaining, however, for a long period his habit of fighting with other males to establish his claim to the woman of his choice. And at last, in his later development in civilized lands, he has abandoned the more obvious arts of courtship and has taken to decorating his womankind instead of himself. He has made woman take over the habit of courtship by the fascination of colour and pose whilst he looks on in sombre clothing with thoughtful reserve. He does not any longer even rely on his strength or skill in fighting in order to scatter his rivals, but makes appeal by word to the sympathy of the desired mate and trusts to the fascination which the power, given either by superior intellectual quality or by accumulated wealth, have for her.