food is attained. To feed well causes lower organisms to pass rapidly and surely over the stages of growth, while insufficient CHANGES IN THE SENSES AND THE VOICE H nourishment causes arrest, whether in larva or child. A well- balanced dietary is especially necessary at adolescence, when the range of appetite normally enlarges and creatures pre- viously monophagous become polyphagous, and it is hard to adopt new kinds of food after the close of this period. Bad eating habits, either in quality or quantity, are at the bottom of most breakdowns in student life, and one of the chief causes of intemperance. Thus every part of the body is constantly undergoing chemico-vital changes, and in the extracts of the six pounds of food and drink, which an adult working man consumes daily, and which are poured through the thoracic duct into the blood, every organ which is irrigated should find and be able to extract the nutriment it needs.
At the very dawn of puberty there is a marked change in the amount of food required which does not vary directly with the rate of 'growth or even exercise; but there are many facts which suggest some unknown cause or process, as if the catabolic changes were modified some months before the body begins permanent augmentation. There is generally a new relation to food. Appetite is often freaky, irregular, capricious, seeking a new equilibrium and larger variety, and the relation among the staple foods finally settled on almost always changes. Sometimes food that is too highly seasoned or too hot, or that in which desserts predominate and overload a sluggish stomach, and perhaps those which have aphrodisiac action, as Marro thinks the case with legumes of the garlic class, or tea, coffee, wine, beer, alkaline or acid drinks, may be almost passionately desired. Indeed, the instability of appetite in both sexes often suggests that of pregnancy. The sense of taste becomes in some degree independent and desires stimulants, condiments, and sometimes intoxicants. The rhythm of meal-times often tends to break up as if by a new \vave of influences from the irregularities of the savage life of our forebears. In nervous temperaments, especially, food is bolted and breakfast slighted, and love of occasional excessive gorging on edibles not hitherto staple, alternates with indifference to or criticism of the family table.
When we pass to detail, the data are not entirely har- monious. It is now generally held that while the amount of both solid matter and water taken into the body increases 12 THE PSYCHOLOGY OF ADOLESCENCE greatly, indeed, nearly doubles from the age of nine to maturity, both steadily decline per kg. of body weight — solids from 14.4 to 9.1 and water from 60 to 44.8.1 Other later data seem to indicate that while the albuminoids and carbohydrates are not greatly changed in relative amount, there is some decrease in the relative proportion of fat and an increase in the sugar in- gredients of food. Camerer constructed with great labor the following table showing the changes in the quality and quantity of food from the ages of eleven to eighteen: GIRLS.
BOYS.
Age...1 Average weight, kg Total food, kg Fat Carbohydrates.
Water Taste is a chemical sense which seems often to improve through life and sometimes to develop to an exquisite degree of sensibility in old age. It is the doorkeeper at the entrance to the alimentary canal, and the human face, including nose and eyes, which are primarily food-finders, and the jaws, which are triturators, have developed as accessories. All the higher meta- bolism depends upon keeping the appetite true to the needs of the body, like a somatic conscience always pointing steadfastly toward the undiscovered poles, the one of nutritive need and the other of human destiny. Taste is perhaps even harder to explore by experimental methods than smell, and no good laboratory age tests are available. Whether the special organs of taste on the tongue or the gustatory surface is modified at adolescence in either extent, discriminative sensibility, thresh- old value, or reaction time, we have no demonstrable knowl- edge. From Horn's experiments with eighty-eight tolerably pure substances down to the latest explorations of this sense, we do not find one thorough and valid test for even the chief stages of life.
We have, however, a large body of questionnaire returns 1 Vierordt: Daten und Tabellen, p. 214.
CHANGES IN THE SENSES AND THE VOICE 13 which suggest with more or less probability that the following modifications are likely to occur: first, there is a change of appetite, often very marked at this age, or a psychic transvalu- ation of tastes. Milk, often taken copiously and with zest be- fore, now becomes unpleasant, and the proportion of solid food desired increases. We know that the jaw-bone grows strong, the chin prominent, and the muscles of mastication increase, causing a general modification of the aspect of the face. Con- nected with this, perhaps, is the propensity to chew and to eat substances that require stronger action of the jaw. The very prevalent gum-chewing habit, which culminates now, is another expression of this age. But, on the other hand, there is often a new tendency to bolt food unchewed, due perhaps to more impetuosity of appetite or the increased nerve tension, and tem- porary loss of the poise that good table manners suggest in this respect. Nearly all who have answered the question, report that at this age many foods seem to taste differently. Many now incline to more, and others to less, vegetable food than be- fore. Animal food is almost always more, but sometimes less, in demand than before, and there is nearly always a change in this respect. While the taste for sweets is sometimes dimin- ished, it is often increased, but the propensity for mild acids is greatly augmented, and still more so that for sodas or alka- lies. The propensity for bitter tastes undergoes also a distinct increase. All this indicates that the range of likes is normally widened.
Mr. Bell found a desire to taste everything that could be carried to the mouth regardless of its edible qualities — grass, plants, soap, worms, bugs, ink, — one hundred and eighty different objects being enumerated; but this desire was al- ready declining at the age of four or five. Later, he thought, came a propensity to make and taste unusual mixtures of food and drink, or to taste foods in their stages of preparation — one hundred and twenty articles being enumerated — culminating between seven and ten. Adolescent curiosity vents itself on new articles in a bill of fare, new flavors, etc. During or often before this transition stage there is a period of unsettlement, fluctuation, and freakiness. New flavors or savors are craved; there are appetites unknown before, and old foods, formerly favorites, now become indifferent. There is a lickerish dainti- 14 THE PSYCHOLOGY OF ADOLESCENCE ness, and it would seem that this upsetting often coincides with a new love of spices, condiments, or very strong stimuli which sometimes incline to the various toxic habits. It is as if taste now had a somewhat more independent value in itself, became more inward and more associated with the Gememgefuhle on the one hand, and more objectified on the other.
Another of the most marked tendencies of this age is that to regulate appetite by psychic motives. New tastes for objects at first unpleasant are often persistently cultivated, perhaps for social or very often for reasons thought to be scientific. Various foods or drinks are affected, because they are more associated with adult habits; the stern dietary of the training table is per- haps imitated, and instinctive likes and dislikes are braved and bullied according to some preconceived scheme. Semper and others have brought forward evidence that in animals this is a plastic period when many become more polyphagous, e. g., that bears may learn to eat oats, and horses to even eat hens, and they have shown how difficult it is to adopt new food after sexual maturity.
All this shows the extreme hygienic necessity at this stage that eating habits should receive special attention, and that all picae and special likes and aversions which interfere with a well-balanced and comprehensive dietary should be avoided, if youth is to utilize the full impulsion of this period which the human as well as the insect larva needs to bring it out to the imago stage of full maturity. All suggests that excessive tea- ism, coffeeism, etc., predilection for tidbits, condiments, and desserts, to the prejudice of appetite for plain, wholesome nu- tritives, and all the special dislikes for standard foods now so common, if not themselves signs of arrest, at least jeopard the highest maturation of powers.
Impatient as adults often are at the eccentricities of juve- nile appetites and the proneness to time-irregularities in both sexes, these probably have their justification within limits. This is the age when at early tropical majority youth in primitive society cut loose from parental aid in procuring food supply and set up for themselves in new environments, before they \vere fully skilled in the arts both of providing and preparing food, and so at a time when the irregularities always found in savage life were increased. Probably seasonal variations due CHANGES IN THE SENSES AND THE VOICE 15 to changes from scantiness and abundance will be made out when the facts are all in, and these will no doubt be found in kind as well as in amount of food. No creature ever began to have such a wide variety and range of dietary as man, for, while his teeth and digestive organs are about as well adapted to fungivorous as to carnivorous habits, commerce now enables him to command the products of every clime and to insure con- stancy and abundance in advance with no direct effort, and this is a transforming and comparatively recent condition. Many tribes, like many animals, are still fat and sleek in the fall and lean in the spring, and alternate at every season between feast- ing, potlucking, and famine or incipient starvation. In some animals, and among some northern tribes which still show a marked breeding season, this is attended by greatly reduced appetites and by maceration. Prolonged periods of exception- ally sustained activity are often concomitant with reduced eat- ing, commonly and perhaps primarily the cause, but sometimes, and it may be secondarily, the effect of unwonted effort. Thus the phyletic presumption is that traces of these racial experi- ences should be more or less faintly rehearsed at this period. If so, this is the way of nature and should be frankly recognized. Happy the youth who comes up to full maturity un- stunted by perversions, excess or defect, and with true, trust- worthy appetite and regular eating habits. Probably no period and no condition of life suffers reduced vitality and efficiency from errors in diet so much as brain-working and sedentary youth, despite the fact that none can better sustain such errors, so far as life and tolerable health are concerned.
III. Smell. — The sense of smell in adult man is about as undeveloped as was the color sense in the remote and some- what conjectural age, which Magnus describes for the chro- matic sense when colors had no independent names, but were designated by those of objects represent! vely colored. It is still hard to distinguish gustatory, olfactory, and often the tactile elements " in all the smells of earth's great kitchen." H. Clo- quet's * mystic and almost poetic interpretation of olfaction as presiding over man's relation to everything vaporized or vola- tile; his view that odors make the birds sing, or rather, as he 1 6 THE PSYCHOLOGY OF ADOLESCENCE thought, laugh, and are the chief link between the flora and the fauna; that those who eat and drink least best understand and appreciate this highly spiritual sense; that odors were long man's chief duty to the gods, who were known by their ambro- sial aura; that the world of smells is that of Democritus and brings man into rapport with cosmic emanations; that Moham- med was right when he called odors one of the two chief joys of life, which had their own mystic language; that in India, titles and degrees of distinction are designated by odors; that fumi- gation keeps off evil spirits; that man prays to Heaven with incense; that perfumes compel the good-will of those about us; that they are carminative and generally medicinal; that the clairolfactant or hyperosmic soul perceives more than the clair- audient or clairvoyant, and the implication that if we ever fully know the higher osmograms of aphrodisiacs and the aura semi- nalis, love itself may be raised to a higher level — of all this we can perhaps only say, Periculum est credere aut non credere.
Olfactory sensations are phylogenetically among the first to associate themselves with sex, and are perhaps the first to be differentiated from general sensibility. This stage is still seen in reptiles and amphibians whose cortex is chiefly olfac- tory. In the infant, smell is one of the earliest senses, and Soury says thought begins in it.1 Although in man, its original role of conserving the individual in helping him to find food and to avoid enemies is slight, it still has very close association with the reproductive function. Althaus long ago urged that the primary function of the olfactory sense was to facilitate reproduction, and cited many cases of animals detecting the female in rut at great distance. Schiff performed the crucial experiment of extirpating the olfactory centers in young dogs, and found that when they had grown to maturity they did not distinguish sex. The odor of the body, and especially of parts of it, which Jaeger thinks to be the essence of the soul, is often a very powerful aphrodisiac. Mantegazza tells of a lady who took such great pleasure in smelling a flower that it seemed to her like a sin. Fere, quoted by Roux, tells of a young man who sneezed whenever he had an erotic thought, and many facts show a very close sympathy in both health and disease between i See also Roux: Psychologic de 1'Instinct Sexuel, p. 72.
CHANGES IN THE SENSES AND THE VOICE 17 the pituitary surface of the nose and sex. Marro found that the sense of smell was most exquisitely developed in girls at the commencement of puberty. An old saw has it that when young people have the nosebleed they are in love. Hemor- rhages from the nose are quite common in puberty and adoles- cence.1 The closeness of this relation appears from the fact that congestion of the turbinated bodies is common during menstruation, when it may embarrass nasal respiration, cause headaches, and even act. vicariously for the normal discharges. Sneezing sometimes accompanies sexual excitement, and nasal catarrh and the fetor of ozena are more pronounced. Often after the menopause, atrophic rhinitis is found. The pain of dysmenorrhea is often relieved by applying cocaine to the so- called genital spots or the erectile tissue over the turbinal and septum. This relation is often seen in the fact that castration of young animals interferes with the development of this tissue. So far, no thorough and adequate laboratory tests of the development of smell during the different stages of life have been made, unless we except those of Marro, who attempted to measure the acuteness of smell with Zwardemaker's olfac- tometer, by the maximum distance at which odors could be perceived when a uniform surface and intensity of olfactory sub- stance were exposed, with the following results in millimeters: SUGAR OF LICORICE. CAOUTCHOUC. VANILLA. MUSK.
Right. Left. Right. Left. Right. Left. Right. Left GIRLS.
Under fourteen — 39 cases.
From fourteen to eighteen— 15 cases.
Over eighteen — 13 cases.
BOYS. Under fourteen— 15 cases.
From fourteen to eighteen — 10 cases.
Over eighteen— 5 cases.
1 The Relation of the Nose to the Reproductive Organs. By C. N. Cox. Brooklyn Med. Jour., July, 1902.
1 8 THE PSYCHOLOGY OF ADOLESCENCE Besides these somewhat inconclusive tests, Marro repeated them on boys and girls in public institutions, taking note in each case whether each was pubescent. Although he used so few substances that for this reason alone his conclusions seem less broadly based than we could wish, we have perhaps no better inference than his, which is, in fine, that women have more olfactory sensibility than men, and that there is an augmentation in girls at puberty. This seems especially pronounced for musk, a strong sex perfume. From fourteen to eight- een many girls, it would appear, are slightly osmosmic for vanilla, caoutchouc, and licorice, their olfactory perceptions being more acute both before and after these years. Boys from fourteen to eighteen were more sensitive for each substance except musk than either before or after.
We have, however, a less controlled source of inference in questionnaire returns, which indicate with considerable cer- tainty the following results: First, the perfumes of flowers attract more attention, give more pleasure, and are more finely discriminated near the dawn of adolescence than before. Sometimes this is described as the opening of a new olfactory world. Fragrance becomes henceforth, and especially to young women, a source of exquisite delight, and sometimes sym- phonies of their perfumes are described as if the tone color of this sense now became capable of producing a higher degree of esthetic enjoyment than any other. The interest in flowers is, of course, manifold, but there is reason to think that at no stage of life does it depend more upon pure olfaction. Secondly, most returns specify an increased interest in per- fumes and aromata generally. The immense role these have had in worship and in the development of religious feelings is well seen in Sigismund,1 who gives a scholarly history of their commercial, religious, and cosmetic uses. The adolescent soul rises more easily with fumigation and incense than is possible later in life. Returns show that now girls love the perfumes for hair, breath, garments, writing paper, soaps, smelling bottles and sachet, and that there is the widest range of individual differences both in acuteness and obtuseness of olfactory sensi- bility and in personal preferences and aversions. The psychol- ogy of this sense, too, shows that its associations are strong, but very deep and often subconscious. It is at this period of Die Aromata. Leipzig, 1884.
CHANGES IN THE SENSES AND THE VOICE 19 life that these potentialities by which incense may suggest all the religious emotions, the odor of the flower recall images of sunny meadows, varnish a funeral, the undescribable ship smell a voyage by sea and even nausea, new-mown hay a mass of dim haestevic sensations, are most numerous and active and have greatest power to modify sentiments and enhance sug- gestibility. Thirdly, body odors,1 while they do not reach their maximal intensity, now rise suddenly to far greater dominance. The more rapid metabolism increases them, as sweat now be- comes more copious, as well as of different composition and smell, with sex differentiations in quality, and somatic exhala- tions are more keenly sensed. Bad breath, now for the first time, has great power to blight friendships; the aroma of dis- ease or anything suggesting the intestinal tract, and sweatiness or anything that savgrs of uncleanliness of person or toilet, now becomes an important social factor. Real and sometimes fanci- ful offensive personal exhalations now may become insupport- able, and many are especially sensitized even to defective ventilation. Indeed, we must admit that fantastic as was Jaeger's identification of the soul with a smell, personal odors, sometimes both consciously and unconsciously at this age, affect likes and dislikes. Finally, we must reserve a place conjec- turally for sex odors, which we know become effective with ani- mals at this period of life, and this very probably may have an importance for youth hitherto unsuspected and at present en- tirely (indemonstrable. If we add to all these the flavors and savors which link taste and smell, and take account of intoxi- cants, tobacco, etc., we are again on the old solid ground of statistics, because both these habits, as shown in Chapter V, are especially prone to arise at this period of inception.
Young children seem on the whole rather insensitive to smell, which is currently assumed to be a decadent sense in man. But there is now a period of recrudescence, not so much for any discriminative or noetic value, as for a rather pure sense feeling with a marked emotional tone, as if these sensa- tions themselves were now appreciated for their own sake; as if the scale of pleasure and pain, up and down which they are distributed, was magnified; and as if the impressions which 1 Monin: Les Odeurs du Corps Humaine. Paris, 1886.
20 THE PSYCHOLOGY OF ADOLESCENCE