of night, by the first men that were men, upon a surface emerged from the grinding and roughing of æons of natural travail- and through the Underworld moves an Eden of the beasts that the ages of the mind with all its voyages and conquests cannot belittle, and the years themselves with their everlasting dull tramp could not wither. The books tell us that the cavemen eternized their subjects as a process of magic for securing their stomachful of the ungulates and protecting themselves against the carnivores. But what about this magic of the spirit, this godlike endowment of men unversed in the kindergarten things we civilized perform by the mechanism of unconscious memory, a secondary magic that from the womb of the rock calls into life, perfect life, the teeming herds of their upper day? Here are paintings, sculptures, and engravings of men without government or social classes, without war or buildings, and more careless of their own supreme art than Shakespeare of his manuscripts, since I have seen mammoth superposed on bison, reindeerwild boar on mammoth-bison. Yet they are masterpieces that academy and art school could but lifelessly copy, and remain grandly aloof from all schools, theories, and fashions of art. These savages whose brutalities keep our circulating libraries on a sound financial footing had their dodges, of course line drawings in black and red, shaded black drawings, frescoes in brown or black monochrome, slight or full polychromes, stipples, flat tints, even impressionist designs of reindeer herds. They were craftsmen all through, and worked in their tough and elementary material as though they had made the rocks for the glory of scratching them. But, however astonishing their technical mastery in a medium so intractable, the supreme fact is that the best of their art is flawless, the flower of perfection blossoming in the inchoate beginnings of human life just taken human form. Darwinian and man-i'-th'-street alike are, indeed, so obsessed with their cave-man fantasy that the art of the Cro-Magnons, though known for twenty years, has had no influence whatever upon modern thought. And what an art! Owing to candle and electric light and the superb vandalism of visitors who carve their names upon the first and, of their kind, the greatest works of pictorial art achieved by the human race, many of the drawings are going back to rock. It is hard to seize their outlines. But when you do, the rock, urged, it appears, by some ancestral sigh welling from the abysses of our human being, gives birth, and there, seven hundred feet from the mouth of the cave, and fenced within the primeval darkness, is a little steppe-horse cantering over the meadows and with every line, curve, muscle, and tendon of his workmanlike body realized in some casual strokes with a dash of shading. A bison rampant with eyes of fire, a toy mammoth full of comedy — with these acts of creation taking shape every minute, one might be watching a drama of Genesis. In the Grotte des Eyzies there is the shadow of a bear on the wall and the bear is behind you no, it's only a Magdalenian bas-relief. At Cap Blanc, high up in a scoop of the cliff looking toward the twelfthcentury château of Comarques, square and scowling over three valleys, is a sculptured horse standing in its rock stable with a repose and majesty so profound, and caught and fixed so marvelously, that, as for Dürer, the only draftsman of animals in all the civilized ages who has ever approached these wild artists whose fathers knew the Mousterian ape-men well, Dürer no, would have known his brethren. Here I have said nothing about the beautiful carvings in bone, ivory, and horn of these ancient children who confound the wise. And I have a copy of a laughing horse originally done in reindeerhorn which is a grotesque as authentic as any executed with a ‘kindly malice' on a mediæval capital. It has been the theorists of the cave-man who have lacked a sense of humor. From their Red Sea shells, and from other indications that I cannot go into here, one knows that these uncouth ones had wide intercommunications and practised a cult of life which subsequently in Egypt was systematized into a religion. From their tools, from the Esquimaux who were the lineal descendants of a branch of the CroMagnons, and from the study of other genuinely primitive peoples still in existence, one concludes that the cavemen of the Upper Palæolithic, whose fictitious example has served the modern doctors and preachers of mankind with so many delusions and so criminal a gospel of the nature of man, had peace unbroken in their time. They were not pacifists they never knew there was such a thing as war. Was it from them and their kin that the persistent human tradition of the Golden Age was born? Truly, in the Dordogne they had the right setting for it. THE SENSE OF SMELL1 BY DR. ERIC PONDER CONSIDERING how important they are to us, our five senses have received at the hands of present-day science rather less than their proper share of attention. We know a good deal about the sense of sight, because it is indispensable to us; about the sense of hearing we know less; and when we come to the most primitive of the special senses, that of smell, we know practically nothing at all. Whatever other reasons there may be for this, one is that smell plays a comparatively small part in our modern life; it is a much neglected sense, usually dismissed as being vestigial or undeveloped and scarcely worthy of serious attention. Sensations of smell are perceived by an organ of extreme simplicity, and yet by one 1 From Discovery (London popular-science monthly), March that has extraordinary powers of discrimination; unnoticed though they be, they of all sensations have the greatest effect on our thoughts and emotions. Indeed, the sense of smell, instead of being the last, might well be considered the first of the five, whether we give it this place because of its importance, its primitiveness, or its mystery. It is more nearly connected with our inner emotional life than are the more practically useful senses of sight and hearing, and at the same time a study of it presents more interesting points than most people realize. Sensations of smell, unless you like to count those of touch, are the most elementary sensations we know, occurring as they do throughout the whole scale of animal creation, even in creatures so lowly as the sea anemone. As one might expect, the organ that receives these sensations is in itself simple, consisting of myriads of tiny units, the olfactory cells, whose appearance is invariable throughout the entire animal kingdom. Each little cell is a rod-shaped body ending in an enlargement on which is a cluster of fine hairs; at the other end of the cell is a nerve fibre which, joining with others, forms the olfactory nerve or nerve of smell proceeding to the brain. In man these little cells are restricted to a small area about a square inch in size situated in the deeply seated parts of the nose, the little hairs of the cells projecting into the current of air that is always passing up and down as we breathe. In some animals, such as the dog, the cells occupy a larger area in the nose, while in others, such as the whales and seals, the area is much smaller; indeed, the development of the olfactory organ appears to go hand in hand with the animal's requirements, the dog and the fourfooted tribe obviously needing the sense of smell more than do the seals and whales. In insects the olfactory cells lie in little culs-de-sac in the antennæ and mouth parts, while in the sea anemone they are found on the surface of the skin; wherever they are situated their structure is much the same—just rod-shaped cells with hairs at one end. And wherever they are found there is to be seen lying among them certain pigment cellscells of great importance, as we shall see. Compared with the ear or the eye, the structure of the olfactory organ is therefore one of great simplicity. 'Yes,' you will say, 'but look how much simpler its function is. The nose has only to deal with smells, much simpler things than colors or sounds.' In which remark you are mistaken. The sense of smell possesses an unrivaled power of discrimination, for we can, by this simple organ, detect the most minute quantities of odorous substances in the air we breathe. The special instrument used for finding the sensitivity of the olfactory cells to various odors is called an olfactometer, there being many different forms. One of the most commonly used consists of a porous tube that slides over a fixed metal tube; according to the position of the porous tube, which is impregnated with the odorous substance, a greater or a less quantity of that substance is carried to the nostrils. If the tube is saturated with vanillin, we find that the average person can recognize as little as one thousand-millionth of a gramme. Nor is this the limit, for other substances are recognized in even smaller quantity. This extraordinary power of perception is well enough known to everybody, for we all know that we can detect impurity in the air of a room by the smell, although chemical tests are quite unable to show the presence of impurities. But the sense of smell is not characterized by its power of perception alone; it has just as remarkable a power of discrimination. The variety of odors is unlimited there are all the natural odors, the odors of the plant world and of animals, perfumes belonging to minerals and inorganic material, and the innumerable perfumes of substances synthesized by chemists. Each one the sense of smell can recognize as different; its powers of discrimination are practically unlimited. Although we can recognize and distinguish an enormous number of odors, we can name very few. There used to be a popular parlor game that consisted of smelling a number of unlabeled bottles, each of which contained a substance with a smell, and then naming each substance by its odor. This is a very difficult thing to do, for, although we can generally distinguish between the odors of two substances, even if they are very similar, it is often impossible to name the substances to which the odors belong. The difficulty arises principally from the vagueness with which we speak of smells. While we refer to colors in a definite way, and while we can describe a sound as minutely as we like by giving its pitch and quality, we cannot speak of 'the mouldy smell' or the stuffy smell' with the same precision that we can speak of the color violet or of the sound called a whistle. The sense of smell is devoid of description; it has no language, and from this point of view is indeed undeveloped. The best we can do is to divide odors into ethereal, aromatic, garlicy, disgusting, and nauseating smells - all vague terms, for into each group there fall thousands of different odors, each of which is easily distinguished by us. The simple organ of smell thus appears to have anything but a simple function. We can to some extent understand how the ear and the eye perform their duties, for we are helped by their complex appearance, but what can one make of the olfactory organ a mass of cells with hairs, and a few pigment cells? What key does the structure give us? Very little; it is all too simple, and thus mysterious. Many theories have been put forward, some likely, some impossible, to explain how these cells function; no single one can be accepted without reservation, but it may interest the reader to be told the little we know. Anything we smell must be in a gaseous state, for it has to be carried to the nostrils in the air that we breathe. It may be in the inspired air, as when we smell a perfume, or in the expired air passing from the region of the mouth and throat into the nose, as are the substances that are responsible for the flavor of food and drink; for flavor is not perceived by the sense of taste, but by the sense of smell, as anyone who has had his nose blocked up by a cold will realize. The odorous substance is thus brought into contact with the hairs of the olfactory cells, which are apparently stimulated, and a sensation of smell results. This is agreed; but how does the stimulation occur? Is it chemical, the odorous substance affecting the hairs like a chemical reagent, or is it physical, depending on waves in the air or ether, as is the case in the senses of hearing and sight? Here admitted fact ends, and speculation begins; some people claim that the effect is chemical, and others that it is physical. We seek in vain for any relation between chemical constitution and smell; although certain substances that are called 'aromatics' have both the same odor and a similar chemical constitution, and although certain compounds of arsenic and phosphorus smell of garlic, any relation between chemical composition and odor breaks down completely as we examine it more closely. Artificial and natural musk, for instance, have the same odor, but are chemically utterly different; prussic acid and nitrobenzol smell the same, but are totally unlike in structure. Many other examples could be given of the failure of this suggestion, and we have therefore to seek explanations on other lines. Impressed by this failure, physiologists have been led to suggest that the action of odorous substances may be not chemical but physical. The minute particles of which the substances are made up- particles called molecules are known to be in a state of very rapid vibration, and it is supposed that these rapid movements set up in the surrounding air little waves, just as the movement of a stone sets up ripples on a pond. These tiny waves are then propagated through the air in the nose, and fall on the hairs of the olfactory cells, which are caused to rock to and fro thereby; the movements of the hairs thus set up an impulse in the cell to which they are attached, the impulse is carried to the brain, and there interpreted as a smell. In this way the vibrating molecules act somewhat like a wireless transmitter, and the hairs of the cells like a detector, the principal difference being that the waves, instead of being metres in length, are exceedingly shortshorter, indeed, than the waves of light. Since a molecule of camphor vibrates at a different rate from a molecule of, say, turpentine, each sets up its own particular length of wave; the hairs of the olfactory cells are stimulated in the one case by a wave of a particular length, and in the other by one which is perhaps shorter; in this way it comes about that camphor is recognized as smelling differently from turpentine, and in the same way we can have as many different kinds of smell recognized as there are lengths of wave that can be generated and received. To this theory, too, there are some serious objections, for, if there were not, the sense of smell would not be the mystery it is. According to the theory, prussic acid should smell the same as steam, for the waves generated are identical. Of course, they do not smell the same, for one is odorless while the other smells powerfully of almonds. Thus we have still the unsolved problem; the chemical explanation fails us, and the physical explanation fails us too - neither accounts for the facts, and the sense of smell guards its secrets. It may be, of course, that both theories are true in part, or that the exceptions are only apparent exceptions that would disappear if we knew the facts more fully, but so far we have to admit defeat. Nor does the problem end with the olfactory cells which, because they terminate in nerves, we take to be the principal receiving elements, for it seems that the pigment cells that surround them also play their part in the perception of odors. In some animals whose sense of smell is very acute, such as the dog and the deer, these pigment cells are very prominent, and richly loaded with their colored material. On the other hand, in animals with a poor sense of smell, such as seals, there are very few pigment cells, and in albinos, which have no pigment cells at all, we find the sense of smell almost absent. This fact is well known to sheeprearers in certain parts of the world, for they refuse to rear albino sheep, knowing well that they will be unable, because of their poorly developed sense of smell, to detect poisonous plants, and that sooner or later they will die through eating herbs which their better-equipped brethren would avoid. The part played by the pigment cells also explains why dark-skinned races have a better sense of smell than the white races, and also why our sense of smell becomes more acute as we grow older, older, unlike any other sense, - for with advancing age more pigment is laid down among the olfactory cells. We are perhaps rather apt to look upon the sense of smell as one that is fixed and unalterable; we know that eyesight fails with age, and that the sense of hearing is subject to very diverse modifications, but so fixed an idea have we of the simplicity of the olfactory sense that we never think that equally interesting observations attach themselves to it. As a matter of fact, recent investigations have |