"Among thy fancies, tell me this,What is the thing we call a kiss?I shall resolve ye what it is."—Robert Herrick
"Among thy fancies, tell me this,What is the thing we call a kiss?I shall resolve ye what it is."
—Robert Herrick
Kissing is an extremely ancient habit of mankind coming to us from far beyond the range of history, and undoubtedly practised by the remote animal-like ancestors of the human race. Poets have exalted it, and in these hygienic days doctors have condemned it. In the United States they have even proposed to forbid it by law, on the ground that disease germs may be (and undeniably are in some cases) conveyed by it from one individual to another. But it is too deep-rooted in human nature, and has a significance and origin too closely associated with human well-being in the past, and even in the present, to permit of its being altogether "tabooed" by medical authority.
There are two kinds of "kissing" practised by mankind at the present time—one takes the form of "nose-rubbing"—each kiss-giver rubbing his nose against that of the other. The second kind, which is that familiar to us in Europe, consists in pressing the lips against the lips, skin, or hair of another individual, and making a short, quick inspiration, resulting in a more or less audible sound. Both kinds are really of the nature of "sniffing," the active effort to smell or explore by the olfactory sense. The "nose-kiss" exists in races so far apart from one another as the Maoris of New Zealand and the Esquimaux of the Arctic regions. It is the habit of the Chinese, of the Malays, and other Asiatic races. The only Europeanswho practise it are the Laplanders. The lip-kiss is distinguished by some authorities as "the salute by taste" from nose-rubbing, which is "the salute by smell." The word "kiss" is connected by Skeat with the Latin "gustus," taste; both words signify essentially "choice." But it would be a mistake to regard the lip-kiss as merely an effort to taste in the strict sense, since the act of inspiration accompanying it brings the olfactory passages of the nose into play. Lip-kissing is frequently mentioned in the most ancient Hebrew books of the Bible, and it was also the method of affectionate salutation among the Ancient Greeks. Primarily both kinds of kissing were, there can be no doubt, an act of exploration, discrimination, and recognition dependent on the sense of smell. The more primitive character of the kiss is retained by the lovers' kiss, the mother's kissing and sniffing of her babe, and by the kiss of salutation to a friend returning from or setting out on a distant journey. Identification and memorising by the sense of smell is the remote origin and explanation of those kisses. The kissing of one another by grown-up men as a salutation was abandoned in this country as late as the eighteenth century. "'Tis not the fashion here," says a London gentleman to his country-bred friend in Congreve's "Way of the World." But we have, most of us, witnessed it abroad, and perhaps been unexpectedly subjected to the process, as I once was by an affectionate scientific colleague. Independently of the more ordinary practice of kissing—there is the "ceremonial kiss"—the kissing of hands, or of feet and toes, which still survives in Court functions—whilst the Viennese and the Spaniards, though they no longer actually carry out their threat, habitually startle a foreigner by exclaiming—"I kiss your hands." The Russian Sclavs are the most profuse and indiscriminate of European peoples in their kissing. I have seen a Russian gentleman about to depart on a journey "devoured" by the kisses of his relations and household retainers, male and female. Among the poor in rural districts in Russia this excessive habit of kissing leads to the propagationof the most terrible ulcerative disease among innocent people—as related by Metchnikoff in the lectures on modern hygiene which he gave in London some seven or eight years ago (published by Heinemann).
We may take it, then, that the act of kissing is primarily and in its remote origin an exploration by the sense of smell, which has either lost its original significance, and become ceremonial, or has, even though still appealing to the sense of smell, ceased to be (if, indeed, it ever was so) consciously and deliberately an exercise of that sense. This leads us to the very interesting subject of the sense of smell in man and in other animals. There is no doubt that the sense of smell is not so acute in man as it is in many of the higher animals, and even in some of the lower forms, such as insects. It is the fact that so far as we can trace its existence and function in animals, the sense of smell is of prime importance as distinguishing odours which are associated either with objects or conditions favourable to the individual and its race, or, on the other hand, hostile and injurious to it. It never reaches such an extended development as a source of information or general relation of the individual to its surroundings as do the senses of sight, hearing and touch. It depends for its utility on the existence of odorous bodies which are not very widely present, and are far from universal accompaniments of natural objects. Apart from some pungent mineral gases, all odorous bodies are of organic origin. Even as recognised by the less acute olfactory sense of man, the number and variety of agreeable and of disagreeable scents, produced by various species of animals and plants, is very considerable. But there is no doubt that the number and variety discriminated by such animals as dogs and many of the other hairy, warm-blooded beasts is far greater. The nature of the particles given off by odorous bodies which act on the nerve-endings of the organs of smell of animals, is remarkable. They are volatile; that is to say, they are thrown off from their source and float in the air in a state of extreme subdivision. Unlike the particles which act upon the nerves of taste,they are not necessarily soluble in water, and though often spread through and carried by liquids, are in fact rarely dissolved in water. The dissolved particles which act upon the nerves of taste can be distinguished by man into four groups—sweet, sour, bitter, and saline. But no such classification of "smells" is possible. As a rule mankind confuses the "taste" of things with their accompanying "smell." The finer flavours of food and drink not included in the four classes of tastes are really due to odoriferous particles present in the food or drink, which act on the terminations of the olfactory nerves in the recesses of the nose, and excite no sensation through the nerves of taste.
The part of the brain from which the nerves of smell arise is of relatively enormous size in the lower vertebrates—as much as one fifth of the volume of the entire brain in fishes—a fact which seems to indicate great importance for the sense of smell in those forms. Even in the mammals (the hairy, warm-blooded, young-suckling beasts) the size of the olfactory lobes of the brain and of the olfactory nerves, and the labyrinthine chambers of the nose on which the nerves are spread, is very large, as one may see by looking at a mammal's skull divided into right and left halves. And it seems immoderately large to us—to man—because, after all, so far as our conscious lives are concerned, the sense of smell has very small importance. Yet man has a very considerable set of olfactive chambers within the nostrils and has large olfactory nerves. Not rarely men and women are found who are absolutely devoid of the sense of smell, and the same thing occurs with domesticated cats and dogs. In these cases the olfactory lobes of the brain are imperfectly developed. It is found that men in this condition suffer but little inconvenience in consequence. We are able, through their statements, to ascertain what parts of the savoury qualities of food and drink belong to taste and what to smell. Such individuals do not perceive perfumes, the bouquet of wine, or the fragrance of tobacco, nor can they appreciate the artistic efforts of a good cook. But they are spared the pain of foul smells, and possiblyin this way they may incur some danger in civilised life through not being able to detect the escape of sewer-gas or of coal-gas into a house, or the putrid condition of ice-stored fish, birds, and meat. A friend of my own, who is devoid of the sense of smell, inherited this defect from his father, and has transmitted it to some of his children. I was surprised to find in conversing with him how often I alluded to smells, either pleasant or unpleasant, when (as we had agreed he should) he would interrupt me and say that my remark had no meaning for him.
Some have a far more acute sense of smell than others, and again some men, probably without being more acutely endowed in that way, pay more attention to smells, and use the memory of them in description and conversation. Guy de Maupassant is remarkable as a writer for his abundant introduction of references to agreeable and mysterious perfumes, and also to repulsive odours. But some men certainly have an exceptionally acute sense of smell, and can, on entering an empty room, recognise that such and such a person has been there by the faint traces—not of perfumery carried by the visitor—but of his individual smell or odour. This brings us to one of the most important facts about odorous bodies and the sense of smell, namely, that not only do the various species of animals (and plants) each have their own odour—often difficult or impossible for man, with his aborted olfactory powers, to distinguish—but that every individual has its own special odour. As to how far this can be considered a universal disposition is doubtful. It is probable that the power of discriminating such individual odours is limited (even in the case of dogs, where it is sometimes very highly developed), to a power of discriminating the distinctive smells of the individuals of certain species of animals, and not of every individual of every species. Everyone knows of the wonderful power of the bloodhound in tracking an individual man by his smell, but dogs of other breeds also often possess what seems to us extraordinary powers of the kind. On a pebbly beach I pick up one smooth flintpebble as big as a walnut. It is closely similar to thousands of others lying there. I hold it in my hand without letting my fox-terrier see it, and then I throw it. It drops some eighty yards off among the other pebbles, and I could not myself find it again. But the dog runs forward, notes vaguely by ear and by eye the spot where it strikes, and then commences a systematic circling within about ten yards of the spot. In half a minute he pounces with the utmost assurance on to one selected stone, and brings it to me. It is invariably the stone which had been in my hand, unseen by the dog, thrown by me, and detected by the smell I have communicated to it.
Not only is the discrimination of individuals by the sense of smell a very astonishing thing, but so also is the obvious fact that the total amount of odoriferous matter which is sufficient to give a definite and discriminative sensation through the organ of smell is of a minuteness beyond all calculation or conception. These two facts—the almost infinite individual diversity of smell and the almost infinite minuteness of the particles exciting it—render it very difficult to form a satisfactory conclusion as to the nature of those particles. It has been from time to time suggested that the end organs of the olfactory nerves may be excited, not by chemically active particles, but by "rays," olfactive undulations comparable to those of light. Physicists have not yet been able to deal with the problem, but the recent discoveries and theories as to radio-active bodies such as radium may possibly lead to some more plausible theory as to the diffusion and minuteness of odorous particles than any which has yet been formulated. An example of the minuteness of odoriferous particles is afforded by a piece of musk which for ten years in succession has given off into the changing air of an ordinary room "particles" causing a readily recognised smell of musk, and yet is found at the end of that time to have lost no weight, that is to say, no weight which can be appreciated by the finest chemical balance. An analogy (I say only an analogy, a resemblance) to this is furnished by a pinch of thesalt known as radium chloride, no bigger than a rape-seed, and enclosed in a glass tube, which will continue for months and years to emit penetrating particles producing continuously without cessation most obvious luminous and electrical effects upon distant objects, the particles being so minute that no loss of weight can be detected in the pinch of salt from which they are given off.
The sense of smell is of service to animals—
(1) In avoiding enemies and noxious things.
(2) In tracing and following and discriminating prey or other food.
(3) In recognising members of their own species and individuals of their own herd or troop, and in finding their own young and their own nests.
(4) In seeking individuals of the opposite sex at the breeding season.
It is in connection with the last of these services that we come across some of the most curious observations as to the production and perception of odorous particles. Butterflies and moths and some other insects have olfactory organs in the ends of the antennæ and the "palps" about the mouth. The perfumes of flowers have been developed so as to attract insects by the sense of smell, as their colours have been also developed to attract insects by the eye. The insects serve the flowers by carrying the fertilizing pollen from one flower to another, and thus promoting cross-fertilization among separate individual plants of the same species. But probably concurrently with this has grown up the production of perfume by the scales on the wings of moths and butterflies—perfumes which have the most powerful attraction for the opposite sex of the same species. Curiously enough (for these perfumes might very well exist without being detected by man) some of the perfumes produced by butterflies are "smellable" by man. That of the green-veined white is described as resembling the agreeable odour of the lemon verbena. It is produced by certain scales on the front border of the hinder wings of the male insects, and not at all by the females, who are, however, attracted by it, andflutter around the sweet-smelling male. Other male butterflies produce a scent like that of sweet briar, others like honeysuckle, others like jasmine, and so attract the females. Other butterflies are known which produce repulsive odours, and so protect themselves from being eaten by birds and lizards. Again, there are moths (for instance, the emperor moth, Saturnia), the females of which produce a perfume which attracts the males, and is of far-reaching power. The French entomologist, Fabre, placed one of these female moths in a box covered with net-gauze, and left it in a room with open window, facing the countryside. In less than an hour the room was full of male emperor moths—more than a hundred arrived, although none had been previously visible in the neighbourhood. They crowded over the box, and even afterwards, when the female moth had been removed, the perfume remained in the box, and the male moths eagerly sought it. The perfume must have carried far from the room where the female was, out into the woods where it was perceived, and followed up to its source by the male moths.
Such perfumes are very generally produced by little pockets or glands in the skin, the secretion having, in the case of insects, birds and mammals, an oily nature. In mammals they are largely produced by both males and females, and serve to attract the sexes to one another. Hairs are situated close to the minute odoriferous glands and serve an important part in accumulating and diffusing the characteristic perfume. Musk and civet are of this nature, and it is a significant fact that these substances are used as perfumes by human beings. It would seem as though mankind had lost either the power of satisfactorily perceiving the perfumes naturally produced by the human skin, or that the production of such perfumes had for some reason diminished. Either condition would account for the use by mankind of the perfumes of other animals and of flowers. There are a variety of odorous substances produced by different parts of the human body, of which some are agreeable and others disagreeable. One of the most curious facts in regard to odorous bodiesis the close resemblance between agreeable and repulsive odours, and the readiness with which the judgment of human beings may pronounce the same odour agreeable at one period or place, and disagreeable at another. There also seems to be a "dulling" of the power to perceive an odour which is a consequence of constant exposure to that odour. Thus the Chinese say that Europeans all smell unpleasantly, the odour resembling that of sheep, although we do not observe it; whilst Europeans notice and dislike the smell of the negro, a smell of the existence of which he is unaware. The blood of animals, including that of man, has, when freshly shed, a smell peculiar to the species, which has not, however, any resemblance to that of the skin or of the waxy glands of the same animal.
It seems that in regard to the exercise of the sense of smell by man, we must distinguish not only greater from less acuteness and variety of perception, but in the case of this sense-organ, as in regard to the others, we must distinguish "unconscious" from "conscious" sensation. All our movements are guided and determined by sensations to touch and sight, and to some extent, of hearing, of which we are unconscious. A vast amount of our sense-experience comes to us and is recorded without our having consciousness of anything of the kind going on. It is probable that the world of smells in which a dog with a fine olfactive sense lives, produces little or nothing in the dog's mind which is equivalent to our conscious perception of degrees of agreeable and disagreeable odours. The dog is simply attracted and repulsed in this direction and in that by the operation of his olfactive organs, without, so to speak, giving any attention to the sensation which is guiding him or being "aware" of it. No doubt at times, and with special intensities of smell, he is, in his way, conscious of a specific sensation. It is probable that whilst man's general acuteness in perceiving and discriminating smells has dwindled (as has that of the apes) in comparison with what it was in his remote animal ancestry, yet he retains a large inherited capacity of unconscious smell-sense, which most of us are unableto recognise, although it is there, operating in ourselves unknown to us and unobserved. The consciousness of smell-sensations is what we value and talk of. It does not extend to the more primal smell-excitations, except in extraordinary individuals. Thus, it seems to be not improbable that we are attracted or repelled by other human individuals by the unconscious operation upon us of attractive or repulsive odours, and that the unaccountable liking or disliking which we sometimes experience in regard to other individuals is due to perfumes and odours emanating from such persons, which act upon us through our olfactory organs without our being conscious of the fact. It seems that we can thus arrive at a probable explanation of the universality of the habit of kissing, and of "what is that thing we call a kiss." It is not consciously used among civilised populations as a deliberate attempt to smell the person kissed, but it nevertheless serves to allow the unconscious exercise of smell-preference, testing, and selection, with which are mingled, more or less frequently, moments of conscious appreciation of the complex of odours appertaining as an individual quality to the person kissed.
LAUGHTER
The ancients associated laughter with the New Year. I am not sure whether or no it is of good omen to begin the New Year with laughter. Omens are such tricky things that I have given up paying any attention to them. One would think it might be held to be unlucky to stumble on the doorstep as you set out from home, but the old omen-wizards, apparently from sheer love of contradiction, said, "Not at all! It is unlucky to stumble as you come into the house, and therefore it is lucky to stumble as you go out!"
What is laughter? It is a spasmodic movement of various muscles of the body, beginning with those which half close the eyes and those which draw backwards and upwards the sides of the mouth, and open it so as to expose the teeth, next affecting those of respiration so as to produce short rapidly succeeding expirations accompanied by sound (called "guffaws" when in excess) and then extending to the limbs, causing up and down movement of the half-closed fists and stamping of the feet, and ending in a rolling on the ground and various contortions of the body. Clapping the hands is not part of the laughter "process," but a separate, often involuntary, action which has the calling of attention to oneself as its explanation, just as slapping the ground or a table or one's thigh has. Laughter is spontaneous, that is to say, the movements are not designed or directed by the conscious will. But in mankind, in proportion as individuals are trained in self-control, it is more or less completely under command, and in spite of the most urgent tendency of the automatic mechanism to enter upon the progressive series of movements which we distinguish as (1) smile, (2) broad smile or grin,(3) laugh, (4) loud laughter, (5) paroxysms of uncontrolled laughter, a man or woman can prevent all indication by muscular movement of a desire to laugh or even to smile. Usually laughter is excited by certain pleasurable emotions, and is to be regarded as an "expression" of such emotion just as certain movements and the flow of tears are an "expression" of the painful emotion of grief and physical suffering, and as other movements of the face and limbs are an "expression" of anger, others of "fear." The Greek gods of Olympus enjoyed "inextinguishable laughter."
It is interesting to see how far we can account for the strange movements of laughter as part of the inherited automatic mechanism of man. Why do we laugh? What is the advantage to the individual or the species of "laughing"? Why do we "express" our pleasurable emotion and why in this way? It is said that the outcast diminutive race of Ceylon known as the Veddas never laugh, and it has even been seriously but erroneously stated that the muscles which move the face in laughter are wanting in them. A planter induced some of these people to camp in his "compound," or park, in order to learn something of their habits, language, and beliefs. One day he said to the chief man of the little tribe, "You Veddas never laugh. Why do you never laugh?" The little wild man replied, "It is true; we never laugh. What is there for us to laugh at?"—an answer almost terrible in its pathetic submission to a joyless life. For laughter is primarily, to all races and conditions of men, the accompaniment, the expression of the simple joy of life. It has acquired a variety of relations and significations in the course of the long development of conscious man—but primarily it is an expression of emotion, set going by the experience of the elementary joys of life—the light and heat of the sun, the approach of food, of love of triumph.
Before we look further into the matter it is well to note some exceptional cases of the causation of laughter. The first of these is the excitation of laughter by a purely mechanical "stimulus" or action from the exterior, without any corresponding mental emotion ofjoy—namely by "tickling," that is to say, by light rubbing or touching of the skin under the arms or at the side of the neck, or on the soles of the feet. Yet a certain readiness to respond is necessary on the part of the person who is "tickled," for, although an unwilling subject may be thus made to laugh, yet there are conditions of mind and of body in which "tickling" produces no response. I do not propose to discuss why it is that "tickling," or gentle friction of the skin produces laughter. It is probably one of those cases in which a mechanism of the living body is set to work, as a machine may be, by directly causing the final movement (say the turning of a wheel), for the production of which a special train of apparatus, to be started by the letting loose of a spring or the turning of a steam-cock, is provided, and in ordinary circumstance is the regular mode in which the working of the mechanism is started. The apparatus of laughter is when due to "tickling" set at work by a short cut to the nerves and related muscles without recourse to the normal emotional steam-cock.
Then we have laughter which is purely due to imitation and suggestion. People laugh because others are laughing, without knowing why. This throws a good deal of light on the significance of laughter. It is essentially a social appeal and response. Only in rare cases do people laugh when they are alone. Under conditions which in the presence of others would cause them to laugh they only "chuckle" or smile, and may, though ready to burst into laughter, not even exhibit its minor expressions when alone. On the other hand, some sane people have the habit of laughing aloud when alone, and there is a recognised form of idiocy which is accompanied by incessant laughter, ceasing only with sleep. Then there is that peculiar condition of laughter which is called "giggling," which is laughter asserting itself in spite of efforts made to restrain it, and frequently only because the occasion is one when the "giggler" is especially anxious not to laugh. This kind of "inverted suggestion," as in the case where an individual "blurts out" the very word or phrase which he isanxious not to use, is obviously not primitive, but connected with the long training and drilling of mankind into approved "behaviour" by "taboos" and restrictive injunctions. Efforts to behave correctly, by causing anxiety and mental disturbance in excitable or so-called "nervous" subjects, lead to an over mastering impulse to do the very thing which must not be done!
It seems that laughter has its origin far back in the animal ancestry of man, and is essentially an expression to others of the joy and exhilaration felt by the laugher. It is an appeal through the eye and ear for sympathy and comradeship in enjoyment. Its use to social animals is in the binding together of the members of a group or society in common feeling and action. Many monkeys laugh, some of them grinning so as to show the teeth, partly opening the mouth and making sounds by spasmodic breathing, identical with those made by man. I have seen and heard the chimpanzees at the Zoological Gardens laugh like children at the approach of their friend and my friend, the distinguished naturalist, Mr. George Boulenger, F.R.S., recognising him among the crowd in front of their cage when he was still far off. And I have often made chimpanzees laugh—"roar with laughter," and roll over in excitement—by tickling them under the arms. The saying of Aristotle (inscribed over the curtain of the Palais Royal Theatre in Paris) that "Laughter is better than tears, because laughter is the speciality of man," is not true. Not only do the higher apes and some of the smaller monkeys laugh, but dogs also laugh, although they do not make sounds whilst indulging in "spasms of laughter." But their distant cousin, the hyena, does laugh aloud, and its laughter agrees with that of the dog and with the laughter of children and grown men in simpler moods in that it is caused by the pleasurable emotion set up by the imminent gratification of a healthy desire. The hyena laughs, the dog grins and bounds, the child laughs and jumps for joy at the approach of something good to eat. But it is a curious fact that the whole attitude is changed when the food is within reach, and the serious business of consuming it has commenced! Nor, indeed,is the satisfaction which is felt after the gratification of appetite accompanied by laughter. It seems that the display of the teeth by drawing back the corners of the mouth, which is called a "grin," and is associated in many dogs with a short, sharp, demonstrative bark, and in mankind with the cackle we call a "laugh," is a retention, a survival, of the playful, good-natured movement of gently biting or pulling a companion with the teeth used by our animal ancestors to draw attention to their joy and to communicate it to others. Gradually it has lost the actual character of a friendly bite; the fore-feet or hand pull instead of the teeth; the sound emitted has become further differentiated from other sounds made by the animal. But the movement for the display of the teeth, though no longer needed as a part of the act of gripping, remains as an understood and universal indication of joy and kindly feeling. So universal is it that this friendly display of the teeth under the name "smile" is attributed to Nature, to Fortune, and to deities by all races of men when those powers seem to favour them.
Laughter is, then, in its essence and origin, a communication or expression to others of the joyous mood of the laugher. There are many and strangely varied occasions when laughter seizes on man, and it is interesting to see how far they can be explained by this conception of the primary and essential nature of the laugh, for many of them seem at first sight remote from it. There is, first of all, the laughter of revivification and escape from death or danger. After railway accidents, earthquakes, and such terrible occurrences, those who have been in great danger often burst into laughter. The nervous balance has been upset by the shock (we call them "shocking accidents"), and the emotional joy of escape, the joy of recovered life, asserts itself in what appears to the onlooker to be an unseemly, an unfeeling laugh. It is recorded that one of the entombed French coal miners, who two years ago were imprisoned without food or light for twenty days a thousand feet below in the bowels of the earth, burst into a ghastly laugh when he was rescued and brought to the upper aironce more. The Greeks and Romans in some of their festal ceremonies made the priest or actor who represented dead nature returning to life in the spring, burst into a laugh—a ceremonial or "ritual" laugh. Our poets speak of the smiles, and even of the laughter of spring, and that is why laughter is appropriate to New Year's Day. It is the laughter of escape from the death of winter and of return to life, for the true and old-established New Year's Day was not in mid-winter, but a quarter of a year later, when buds and flowers are bursting into life. It is recorded by ancient writers that the "ritual laugh" was enforced by the Sardinians and others who habitually killed their old people (their parents) upon their victims. They smiled and laughed as part of the ceremony, the executioners also smiling. The old people were supposed to laugh with joy at the revivification which was in store for them in a future state. So, too, the Hindoo widows used to laugh when seated on the funeral pyre ready to be burnt. So, too, is explained (by Reinach) the laughter of Joan of Arc when she made her abjuration in front of the faggots which were to burn her to death. Her laugh was caused by the thought of her escape from persecution and of the joyful resurrection soon to come. It was not an indication that she was not serious, and that her abjuration of witchcraft was a farce, as her enemies asserted.
More difficult to explain is the laughter excited by scenes or narrations which we call ludicrous, funny, grotesque, comic; and still more so the derisive and contemptuous laugh. Caricature or burlesque of well known men is a favourite method of producing laughter among savages as well as civilised peoples. Why do we laugh when a man on the stage searches everywhere for his hat, which is all the time on his head? Why do we laugh when a pompous gentleman slips on a piece of orange-peel and falls to the ground, or when one buffoon unexpectedly hits another on the head, and, before he has time to recover, with equal unexpectedness hooks his legs with a stick and brings him heavily to the ground? Why did we laugh at theadventures of Mr. Penley in "Charley's Aunt"? In all of these "ludicrous" affairs there is an element of surprise, a slight shock which puts us off our mental balance, and the subsequent laughter, when we realise either that no serious harm has been done or that the whole thing is make-believe, seems to partake of the character of the "laugh of escape." It is caused by a sense of relief when we recognise that the disaster is not real. We laugh at the "unreal" when we should be filled with horror and grief were we assured that there was real pain and cruelty going on in front of us. The laughter caused by grotesque mimicry or caricature of pompous or solemn individuals seems to arise from the same (more or less unconscious) working of the mind as that caused by some unexpected neglect of those social "taboos" or laws of behaviour which we call modesty, decency, and propriety. They either cause indignation and resentment in the onlooker at the neglect of respect for the taboo, or, on the contrary, the natural man, long oppressed by pomposity or by the fetters of propriety imposed by society, suddenly feels a joyous sense of escape from his bonds, and bursts into laughter—the laughter of a return to vitality and nature—which is enormously encouraged and developed into "roars of merriment" by the sympathy of others around him who are experiencing the same emotion and expressing it in the same way.
The laugh of derision and contempt and the laugh of exultation and triumph are of a different character. I cannot now discuss them further than to say that they are either genuine or pretended assertions of joy in one's own superior vitality or other superiority. The "sardonic smile" and "sardonic laughter" have been supposed by some learned men to refer to the smiles of the ancient Sardinians when stoning their aged parents. But they have no more to do with Sardinians than they have with sardines or sardonyx. The word "sardonic" is related to a Greek word which means "to snarl," and a sardonic grin is merely a snarl. In it the teeth are shown with malicious intent, and not as they are in the benevolent appeal of true laughter.Mrs. Grote, the wife of the great historian (who was herself declared by a French wit to furnish the explanation of the word "grotesque"), wrote of "Owen's sugar-of-lead smile"—referring to the great naturalist, Richard Owen. There was no malice in the description, for he had, as some others have, a very sweet smile, accompanied by a strangely grave and disapproving glare in his large blue prominent eyes. It was only apparently sugar of lead; really, it was sugar of milk—the milk of human kindness. The smile of the lost picture called "La Gioconda" is by fanciful people regarded as something very wonderful. It is really the clever portraiture of the habitual "leer" of a somewhat wearied sensual woman. It had a fascination for the great Leonardo, but no profound significance.
FATHERLESS FROGS
One of the most interesting discoveries of recent date in regard to the processes which go on in that all-important material—protoplasm—which is the physical basis of life and the essential constituent of "cells"—those minute corpuscles of which all living bodies are built—was made in 1910 by a French naturalist, M. Bataillon, and has been examined and confirmed by another French biologist, M. Henneguy. To explain this discovery, a few words as to well-known facts are necessary. It is well known that if we isolate a female frog at the egg-laying season and let her swim in perfectly pure filtered water, and proceed to deposit some of her eggs in that water, the eggs will not germinate; they remain unchanged for a time and then decompose—become, in fact, "rotten." It is a matter of common knowledge that it is necessary for the eggs to be "fertilised" in order that they may start on that series of changes and growth which we call "development," and become tadpoles and eventually young frogs. The "fertilisation" of the frog's eggs is effected in ordinary conditions by the presence in the water of the pond, into which the female sheds them, of microscopic sperm-filaments (often called spermatozoa, or simply "sperms") which are shed into the water at the same time by the male frog.
The egg (the blackish-brown spherical body, as big as a rape-seed, which is imbedded in a thin jelly, and is familiar to those who are drawn by curiosity to look into the waters of wayside ponds in spring) is a single cell or corpuscle of protoplasm distended with dark-coloured and other granules of nutrient substance. A single sperm (though requiring the microscope to render itvisible) is also a single cell. It is a minute oval body, with a long serpentine tail of actively undulating protoplasm. Hundreds of thousands of these are shed into the water at the breeding season by the male frog. One is enough to fertilise the egg. The sperm-cells swim in the water, and are chemically attracted by the eggs. As there are so many sperms, one of them is sure to reach each black egg-sphere. It drives its way into the substance of the egg, making a minute hole in its surface; then the protoplasm of the sperm fuses with the protoplasm of the egg, and becomes intimately mixed with it. The egg-cell has a "nucleus," that dense, peculiar, deep-lying, and well-marked "kernel" of its protoplasm which all cells have. It is of essential importance in the life and activity of the cell. The sperm-cell has also a "nucleus," and now (as has been carefully ascertained) the nucleus of the sperm and the nucleus of the egg-cell unite and form one single nucleus. The egg is thereupon said to be "fertilised"—that is to say, "rendered fertile." It at once commences to move. Its surface ripples and contracts and nips in deeply, so that the sphere is marked out into two hemispheres. These are two "cells," or masses of protoplasm, adhering to each other. Each is provided with its own distinct nucleus or cell-kernel, for the first step in the division of the egg-sphere is the division within it of its newly constituted nucleus into two, each half consisting of nearly equal proportions of the mingled substance of the sperm-nucleus and the egg-nucleus. The two first cells or hemispheres again divide, and so the process goes on until the little black egg has the appearance of a mulberry, each granule of the berry being a cell provided with its own nucleus derived from the original nucleus formed by the fusion of the nuclei of the paternal and maternal cells. In the course of a day or two the division has proceeded so far that the resulting "cells" are so small as to be invisible with a hand-glass, and require one to use a high magnifying power in order to distinguish them. And there are hundreds of them; the whole mass of the "egg" within, as well as on the surface, has divided into separate cells. They go onmultiplying, take up water, and nourish themselves on the granular nutritive matter present from the first in the egg-cell. The little mass elongates, increases in size, and gradually assumes the form of a young tadpole.
We see, then that the process of fertilisation consists in two things, the latter of which necessitates the former, viz. in the breaking or penetration of the surface of the egg-cell by the active sperm filament and second in the fusion of the substance of the sperm filament with that of the egg in such a way that there is a distinct and intimate fusion of the nucleus of the sperm filament with the nucleus of the egg-cell. The recent discovery of M. Bataillon is this, viz. that you can make the frog's egg develop in a perfectly regular way and become a tadpole and then a young frog without the admission to it of a sperm-filament or of any substance derived from the male frog. All you have to do—and the operation, though it sounds easy and simple, is an exceedingly delicate and difficult one—is to prick with a fine needle the surface of the little black egg-sphere (not merely of the jelly surrounding it) when it is shed by the female frog into perfectly pure water free from sperms or anything of the sort. The slight artificial puncture acts as does the natural puncture by the swimming sperm-filament, and is sufficient! The egg proceeds to develop quite regularly. There is no fusion of the nucleus of the egg-cell with any matter from the outside; no paternal "material" is introduced, but the nucleus of the egg-cell divides just as though there had been! The whole progeny of cells, successively formed, are the pure offspring of the maternal egg-cell and its nucleus. The tadpoles and young frogs so produced are examples of what is called "parthenogenesis"—that is to say, virginal reproduction—reproduction without fertilisation by material derived from a male parent! The needle, which gives off no material, but simply makes a tiny break in the surface of the egg, does all that is necessary!
To those not acquainted with all that has been ascertained as to the reproduction of lower animals such as insects, crustaceans, and worms, this discovery willappear more astonishing than it really is. We know of many lower animals in which the egg-cells produced by the females do regularly and naturally develop without the intervention of a male and without fertilisation. In an earlier volume[7]of this "Easy Chair Series" I wrote of this curious subject, and described the virgin reproduction or parthenogenesis of the hop-louse and other plant lice, of some moths, of some fresh-water shrimps, and of the queen bee (who produces only drones by eggs which are not fertilised). But I had to point out then that no case was known of "parthenogenesis"—that is to say, reproduction by unfertilised eggs—among the whole series of vertebrate animals, the fishes, amphibians, reptiles, birds, and mammals. The chief point of novelty in M. Bataillon's discovery is that we have now an experimental demonstration of parthenogenesis in a vertebrate animal, and in one so highly organised as the frog. And equally interesting, indeed more important from the point of view as to the real meaning and nature of fertilisation, is the mode in which the parthenogenesis of the frog is set going, namely, by a mere prick of the surface film of the ripe egg!
There have, however, been important experiments on the subject of the development of eggs without fertilisation in recent years, prior to these discoveries as to the frog's egg. A favourite subject for such inquiries is the sea urchin (Echinus of different kinds). The female sea urchin, or sea egg, like its close allies the star fishes, lays a great number of very transparent minute eggs (each about the 1/200th of an inch in diameter) in sea-water, and they are there fertilised by the mobile sperm filaments discharged by the males. The eggs are so transparent and so easily kept alive in jars of sea-water that there is no difficulty in watching under the microscope the penetration of the egg by a sperm, and the fusion and other changes in the nuclei. Delages of Paris, and Loeb of California, have made valuable studies on these eggs. Loeb has shown that they may be artificially started on the course of developmentand cell division without fertilisation—simply by the action of minute quantities of simple chemicals (fatty acids, etc.) introduced into the sea-water by the experimenter. These chemicals appear to act on the delicate pellicle which forms the surface of the egg-cell in much the same way as the prick of a needle acts on a frog's egg. A limited and delicately adjusted disturbance of the cohesion (or of the surface-tension) of the egg-cell seems to be all that is necessary for starting the egg-cell on its career of development. It becomes, in the light of these experiments, not so much a wonder that egg-cells should develop "on their own," but that they do not more frequently do so. It must be remembered that the "germination" and development of unfertilised eggs, even when the whole range of animals and plants is taken into account (for plants also are reproduced by single cells identical in character with the egg-cells and sperm-cells of animals), that is to say, the existence of "parthenogenesis" as a natural, regularly recurring process, is exceptional. We must distinguish cases in which it regularly occurs as part of the life-history of an animal or plant from cases in which it has been successfully brought about by experimental "artificial" methods designed by man. The plant-lice "naturally" reproduce through the summer by unfertilised eggs producing only females, but in the first cold of autumn males are hatched from some of the eggs, and the eggs of this generation are fertilised and bide through the winter, hatching in the following spring. Some few moths and flies also reproduce naturally during summer by unfertilised eggs, and the brine-shrimps and some other fresh-water shrimps produce "fatherless" broods from their eggs, sometimes for years in succession, until "one fine day" some males are hatched, owing to what causes we do not know. The queen bee naturally and regularly lays a certain number of unfertilised eggs, and these produce, not females as do the unfertilised eggs of plant-lice, etc., but male bees—the drones—and it is only from such eggs that the drones of bees are born. These are the chief cases of regular and natural parthenogenesis, but there are others which might be enumerated.
On the other hand, examples of artificially induced development of eggs, not fertilised, are very few. The first known came accidentally to notice. Female silkworm moths reared in confinement sometimes lay eggs when kept apart from the male, and these have been found to hatch, and give rise to caterpillars, which were not reared to maturity. Other moths bred by collectors behaved in the same way, but the grubs were reared to maturity, and three successive generations of "fatherless" moths were obtained. In these cases the hatching of unfertilised eggs is not known to occur in a state of nature, although it probably occurs occasionally. It has also been observed—an important fact when considered with the history of the frog's egg and the needle—that "brushing" the unfertilised eggs of the silkworm and other moths, that is to say, gently polishing the little egg-shells with a soft camel's-hair brush, has the effect of starting development. Taking two lots of unfertilised eggs adhering to slips of paper, as laid by the mother moth, it is found that those gently brushed will hatch, whilst those not brushed will either not hatch at all, or in very small number. The brushing seems to disturb the equilibrium of the protoplasmic egg-cell within the egg-shell just sufficiently to set it going—going on its course of division and development. The only other case of "artificially-induced parthenogenesis" at present recorded is that of the common frog, due to M. Bataillon. There are questions of great interest still to be made out as the result of his discovery. Can the fatherless brood be reared to maturity and again made to yield a fatherless generation? What is the precise structure of the nuclei of the cells which originate from the nucleus of the egg-cell only, and not from a nucleus formed by the fusion of that with a sperm-cell nucleus? These and similar questions are the motive of further careful study now in progress.
The important conclusion is forced upon us by these experiments with a needle, that even in so typical and highly organised a creature as one of the higher or five-fingered, air-breathing vertebrates, the egg-cell does not require any material admixture from the sperm-cell inorder that it may successfully germinate and develop, but only a disturbance of equilibrium, which can be administered as well by a needle's point as by a sperm-filament! Yet the whole process of sexual reproduction undoubtedly has, as its origin and explanation, the fusion in the first cell of the new generation from which all the rest will arise, of the material of two distinct individuals. Thus the qualities of the young are not a repetition of the qualities of one parent, nor are they a mere mixture of the qualities of both parents (for contradictory qualities cannot mix). They are a new grouping of qualities comprising some of the one parent and some of the other and hence a great opportunity for variation, for departure from either parent's exact "make-up," is afforded, and for the selection and survival of the new combination. It is, it would seem, only in exceptional cases and for limited periods that uni-sexual or fatherless reproduction can be advantageous to a species of plant or animal. Such cases are those in which abundant food, present for a limited season, renders the most rapid multiplication of individuals an advantage to the species. But after this exceptional abundance has come to an end, the more usual process of reproduction by fertilised eggs (also necessary and advantageous for the preservation of the race by "natural selection in the struggle for existence" of the new varieties so produced) is resumed until again the abundant food is present, as in the annual history of plant lice and the plants on which they feed.