SCIENCE'FROM AN EASY CHAIR.

Press, Volume L, Issue 14969, 16 May 1914, Page 9

SCIENCE'FROM AN EASY CHAIR.

lII.—COURTSHIP, INSTINCT AND REASON.'

(By Sir Ray Lankester, X.C.8.,

F.R.S.)

(Special rights secured by "The Press.")

Apart from tho familiar instances of male colour decoration afforded by birds, we find that even some of tho minute water-fleas inhabiting i'roshwater lakes and tho sea, and known as .''Crustacea Entomostraca," nut on a courting dress in tho breeding season; that, is to say, the males become brilliantly coloured with patches of red and blue. And among the highest mammals wo find that the same colours are, in some cases, displayed hy tho males as a fascination to the females. This is the case with the males of someof the haboons, though not with those of the highest man-like apes, who, -like •the primitive ''savage" man, havo no decoration, no pretty seductive ways appealing to either the eye or the car, but rely on. their strength and ferocity to overawe and paralyse tho female. In the male "mandrill" baooon the skin of tho sides of the great snout is of a deep blue colour, whilst the nose and a tract behind it is wax-liko and bright red. Not only that, but the buttocks are brilliantly coloured, a central red area passing at the sides through rich purple to p4le blue. The animal, which is often to be seen in menageries, is evidently proud of this finely-colour-ed regions of his body, and turns it to a visitor and remains.quietly posed, so that it nJay be well seen and duly admired. The hindquarters of other monkeys—both- male and female—show a brilliant red colouring during the mating season, and the skin and hair of tho faco is variously coloured, so as to produce a decorate pattern (eyebrows, moustache, beard, nose, all strongly contrasted in colour) in the smaller monkeys, usually more strikingly in the males than in the females. A brilliant emerald-green . patch of colour is shown in tho hinder part of the body of- tho rcale in one species sometimes to bo vseen at Regent's Park. '

The making of sounds is a capacity possessed by many animals, small and big. Often it seems to have no particular significance, ■ but, as in the case of the "humming" of bees aiid flies and the- "droning" of beetles, is the necessary accompaniment of the vibration of the wings. But many animals make sounds as a "call," either to other individuals of their species, irrespective of sex, or more definitely as signals and appeals to the other sex, just" as the luminosity which happens to accompany certain necessary chemical activities in tht>-bodies of the lower animals has .become specialised and utilised in the glowworm and other higher forms as a signal and anneal,. The rubbing of rough surfaces .against one another is developed into a * ; stridufating organ," which ire find in crickets, locusts, scorpions, spiders, and . even in marine Crustacea, and it is often specialised as a.sexual appeal. The mere production of sound by tanning against wood is used by the little beetle, the death ■watch, as a cnll, and is responded to by his innte with similar tapping. Such "tapping , ' is developed. into~a remarkable rhythmic vibrating sound by the birds called woodpeckers, and has ite .significance in courtship. But it is chiefly, by the inspiration and expiration of air over vibrating cords or membranes called "vocal organs" that ani.mals produce distinctive and musicaJ sound.-. In mast cases .such animals have a more general and simple "cry," which is not necessarily a eexrial appeal, but addressed to comrades generally, and also a more elaborate-cry or song which is primarily used by the male as an attraction in courtship, but hae.in the case of many birds been inherited from original male singers by tho females also. Thf> "singing" o f birds —apart from simpler cries and calls— is a sexual address, an act of courtship. It is a display of power and capacity on the part of the male, and that such is its character is shown by the competition between male birds in the endeavour to "out-sing" one another. Some birds become extraordinarily excited in these, competitions, -which take the place of actual fighting, tho victor who silences his opponents being tho winner of the female bird, -who is at hand listeniing to tho competition. Caged chaffinches are celebrated for their eagerness to compete with one another in singing. They deliver their little sons alternatoly until one is exhausted and unable to take up his tarn. He is vanquished. So excited I do the birds become that it occasionally [ happer.c that one of the competitors I drops down dead:, The beginning and directive cause? of the particular song of different kinds of birds is not under--But it is well known that they have a great gift of imitation. Parrots, n jping crows, ravens, and other sneh Wrds are familiar instances, whilst little birds such as buUSnch*\« can he trained to whistle the melodies wbjch beings have invented. Even tfce house-sparrow, which, though allied Wsiugiug finches, never sings at all

when in natural conditions, has been converted into a songster by -bringing it up in company with piping bullfinches.

Other animals which cannot sing like the birds yet use their voices in courtship. Tho frogs and toads are no me-an performers in this way, whilst cats, deer, and other largo animals are ''singers/ of a kind, when stirred by mate-hunger. The monkeys chatter and make various vocal sounds, but tho gibbons and man-like apes produce excessively loud and penetrating cries. These cries, though sometimes of fine note and repeated rhythmically (as in the gibbons and chimpanzees), have not the character of snug. The beginnings of song in mankind are lost in tho mist of ages. The Australian blackfellows chant and dance with rhythmic precision .and a certain kind of melancholy cadence, but they never attempt to fasc-maie the other sex by tho use of the voice (nor, so far as is known, in any other way), and, indeed, there is a vast interval between their vocal performances and the love-songs of modern civilised races. Man has not inherited singing from his animal ancestry, but has re-invented it for himself. His real knowledge and command of ''music" is actually a novelty which has sprung into existence within the last few hundred years.

There is no doubt that animals of the same species are attracted to one another by smell, and that distinct species have distinct smells. Further, there i? no doubt that in many cases the special smell of either sex attracts the other. But modern man has so nearly lost the sense.or smell —why it is difficult to say. excepting that it is because it was not of life-saving value to him, —that it is very difficult for us to estimate properly tho significance of perfumes and odours. We know that the dog has what to us seems a marvellous power of tracking and recognising by smell, and +hat other animals appear to be similarly endowed, though most usually we cannot nercm'vo tho smell at fill which they recognise and follow. It appears that nearly all tho hairy rinndruprrLs have distinctive odours, which +bey and their comnar.ions can readily recognise, secreted by certain Hamls "in the skin placed here and there on the body, often on the \c"2s and toes. Bomo of these odours, like musk and civet, wo can perceive, though most have no effect on us. Tt seoms to be an evidence of the absence of Jinv need for man to T>rocluco "perfumes" by tho action of his own structure that he has a feeble sense oP smell and has co little perception of any perfumes or odours peculiar to himself that ho has -when civilised always made use of odorous substances (perfumes and scents) extracted from other animals and from plants for tho purpose, before the days of cleanliness, of masking {he unpleasant odours of putrescence pervading his body and clothing, and later, when dirt becamo less common, of .giving an agreeable ■\vhiff_ to the olfactory organs of his associates. ~ ,

In insects, for instance, moths and bnttiM-flies, and no doubt in most if not all others, the senso of smell is astonishingly keen, and serves as the great guide and attraction in courtehip, 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 onen window in a country house. In three hours a dozen males of this species had entered the room, but no other moths. In twentyfour 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 imnerceptiblo 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. TJio antenna which carry the olfactory sense-organs are far larger in the. males than in the tomales, as is also the case in many othor lower animals where smell is a guido to mating. A single female of the vapourer moth which is common in tho 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 surrounding plantations, and such is the penetrating and powerful character of tnese odor--ous substances produced by fomalo moths that in one species in which the femalo-is windless and lives under water, the odour escapes through tho water and attracts tho males in quantities to its surface. Tho females then arise from the depths, and like mermaids, or the witch of the Rhine draw the infatuated males beneath the wajter to love and death. In several butterflies it has been shown 'that tho males produce, sweet perfumes on the surface of the wings, "which can bo. detected as such by man, and act as stimulants to the mate-hunger of tho female butterflies, which follow the srenlod male in numbers. Tho sense of smell is thus .seen to be a much more wowerftil guide in insects than might bp supposed, and it is of equally great imnortiiiioo to them in other enterprises and activities of life besides those of oourtshio. It has nlso a leading importance in all the lower and lower-most animals, and is the ultimate guide (for smell and taste are not separable in such simple forms) of the motile sperniHiV; filament in its journey to tho ■egg-cell.

T Jiave in the course of these notes en "Courtship" more than once stated that though man shares in common with all other animals the ultimate impulso to "courtship." namely, '' f niatehunger/' 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, aiid 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-liko ancestors. None of these means of courtship are inherited instincts *or structures in man as they-ire in animals. All have been arrived at and devised by man afresh, as the result of "taking thought." And in the latest advance of civilisation 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 colourc, clothes, plumes, and jewellery, and by exquisite dancing and Not so long ago both sexes of man practised such display, but in earliest times only tho male, the woman being allowed to snort 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 mc; be regarded. There are three great steps in the jrradual evolution of the mind. The first is the slow formation (by variation and survival of the fittest) of transmissible, and, therefore, inherited, mechanisms _>f the mind, which are of various degrees of complexity, and characterise different species and kinds of animals. These mechanisms act like thoso of a "penny-in-the-sk>t machine," and are just as re~ gutarly present, and as much alike in all individuals of a snecies as are the other inherited structures, such as bones, flesh, viscera, the skin and its coloured clothing of decorative feathers or hair.

I'£tor. and added to these inherited mechanisms— often interfering with them and putting an end to them—are the mechanisms "of the second stepThese are mechanisms arising from individual experience: they dopend on

memory—the inscription on "the ta>>lets or the mind," of tho experience that this follows that. Th.n- control movement action, usurping tho privilege ot the previously omnipotent inherited mechanisms or instincts. This secemd step in the development of mind requires an excessive quantity of bniincells. It only makes its appearance at ail m animals with largo brain*, and reaches a far greater development, in ™ au even than iv 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 tho specie*—is obviously a great advaiitage in the struggle 'for existence There are traces ot it in some of the cuttlefish and insects, but even m the tishes and reptiles among """S v ert<?l>rates it is of small account, and the small brain carries oh its work by good, sound, inherited mechanisms or instincts; but learns nothing, comprehends nothing! In the birds wo see a little—a very littlo— more capacity tor learning by individual experience, ami it is only in the larger and later mammals that educabilitv, or the power of learning by individual exl^[ !eIlc c becomes of serious importance. All tho larger living mammals —horse, cattle, sheep, rhinoceros, tapir—have acquired an enormous increase in tho size, of their brains— as much as six or eight times the volume of that of their extinct ancestors whose bones and brain cavities w« find fossilised in the Tertiary strata. Man has by far tho biggest brain of all these animals, and has a uniquo degree of educability, together with tho fewest instincts or inborn hereditary mechanisms among animals. Hβ has practically to learn by , individual experience—and therefore in tho form best suited to his individual requirements—a host of most important actions and behaviours which even monkeys and 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 really "educable" animal. In consequenco of his large brain and its roomy memory he can be, and is—even when a "siivage" —educated. Monkeys and dogs have only smaJl "educability" as compared with man, though more than have reptiles or fishes. Man's mind is, therefore, in this essential featuro very different from that of animals. No doubt it includes some hereditary mechanisms, but in tho main it distinctively consists of nerve-mechanisms, formed by his own individual education, acting on receptive and educablo brain matter. And tho 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 tho development of mind is tho arrival (for one can call it by no other term) of that condition which wo cr.ll "consciousness" —tho power of saying to oneself "I am I," and of looking on as a detached existence not only at other existences but jit one's own mental processes, feelings, and movements. With it comes thought, knowedge, reason, and will. We may speak of consciousness as invading or spreading gradually over tho territory of mind. All tho three steps of i tho growth of mind which I have distinguished can be seen following one on the other in tho growth of a human child from infancy to adolescence. Tho 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 tho inherited mechanisms which wo call

"instincts" aro never within tho roach of consciousness, though, of course, the actions determined by them are. It is a difficult matter to decido how far tho memory of apes, dogs, and such animals nearest to man is oonseions memory. Probably very little. But it is only when memory, as weTT 'as the impression of tho moment, is pervaded by consciousness' that reflection and reason and action dependent on reason is possible.

Hence it is that »*••"> in all tho procedure of courtship trczr-rrZ apart ??bm animals. Even tho Australian has not only an educablo""braTri, but a more or less conscious memory. He seems to bo permanently, in this respect, in the condition of an ordinary European chiid of about five veal's old. briiduaily in the course of the development both -of increased educability and of more and more efficient and BervkifcabfS education, man has first abandoned by slow degrees his violent ancestral methods of procuring a mate, and Sas, as the result of observation, reflection, and conscious reasoning, taken to courtship by persuasion and fascination, similar to that of the Wrds and other remote creatures, retaining, however, for a long period, his habit of fighting with other males to establish his claim to tie woman of Jri& choice. And at last, in his later development in civilised lands, he has abandoned the more obvious arts of courtship and lias taken to decorating his woman-kind instead of himself. Ho has made woman take over the habit of courtship by the fascination of colour and pose, whilst ho 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 uses tho appeal by word to the sympathy of the mate and the fascination which the power, given either by superior intellectual quality or by accumulated wealth, have for her.