In 1878 Harvard University rewarded me for my hard work in the philosophical department (under Professors Bowen and Palmer) by giving me the Harris Fellowship, which enabled me to continue my study of physiological and comparative psychology for three years at the universities of Germany.
I recall vividly my boyish delight in the pleasures of the senses of sight, hearing, and smell. During my college course and afterwards I diligently studied the phenomena of these senses in man and animals in all the books and scientific papers I could find; and thus it came about that my first magazine articles were on the Ãsthetic Value of Odors, and The Development of the Color Sense. The first of these was accepted by W. D. Howells, for the "Atlantic Monthly" (December, 1880); the second, by Alfred Russell Wallace, for "Macmillan's Magazine" (London, December, 1879). I mention these things to show that the senses of man and animals have been a subject of special interest with me for more than four decades, and that when I went to Germany, I took up the study of them not as an amateur but as one prepared (as well as eager) to make original researches.
My most ardent desire was to work in the laboratories of the University of Berlin under Professor Helmholtz, whose monumental books on the sensations of tone and on the phenomena of sight had revealed so many secrets to the world of science. Unfortunately he was not lecturing on those subjects at that time. Moreover, reperusal of his books made me feel as if he had covered all the most interesting ground. I therefore looked about for a region in which I could do some exploring on my own account, and soon found it in the functions of the senses of smell and taste.
Concerning these two senses, the most absurdly incorrect notions were current at that time even among leaders in science. Grant Allen, known as "the St. Paul of Darwinism," voiced the current biological opinion when he wrote that with man "smell survives with difficulty as an almost functionless relic"; and Darwin himself wrote that this sense is "of extremely slight service" to man.
The king of German philosophers, Kant, who was an epicure, maintained that smell is the least important of our senses, and that it is not worth while to cultivate it. Nay, the king of epicures, Brillat-Savarin, wrote a famous book the very title of which, "Physiology of Taste," is a scientific blunder. Like everybody else, he believed in the existence of an infinite variety of tastes, and never suspected that, with the exception of sweet, sour, salt and bitter, all our countless gastronomic delights come to us through the sense of smell.
A NEW PSYCHOLOGY OF EATING.
The French physiologist Longet and the German anatomist Henle were, so far as I could find, the only experts who had an inkling of the gastronomic importance of the sense of smell; but they did not go so far as to formulate the theory I have just expressed in italics. My experiments showed me that not only is it impossible, with the nose clasped (or closed by a cold), to tell the difference between various kinds of meats, or cheeses, or cakes, or vegetables, but also—which no one had ever pointed out—that even in the case of sweet and sour substances which do gratify the palate, the sense of smell is much more important than the sense of taste.
Vinegar, for example, is absolutely uninteresting unless it has a "bouquet"—the aroma of the cider, wine, or malt of which it is made. And why is it that we are willing to pay from five to twenty times as much for candy as for plain sugar? Because the sugar appeals only to the taste, whereas the candy is usually perfumed with the aroma of sarsparilla, wintergreen, vanilla, chocolate, and a hundred other flavoring ingredients the fragrance of which we enjoy by exhaling through the nose while eating it.
The emphasis lies on the word exhaling. It is considered a breach of etiquette to smell of things at the table in the ordinary way, because it implies a doubt as to the freshness of the food. But there is a second way of smelling of which most persons are unconscious, although they practise it daily. Anatomy shows that only a small portion of the mucous membrane which lines the nostrils is the seat of the endings of the nerves of smell. In ordinary expiration the air does not touch this olfactory region. But when we eat in the right way we unconsciously guide the air impregnated with the Flavors of the food we are munching, into that region, and that is the way we enjoy our food. We do this unconsciously, I say; but now try and do it consciously, guiding the expired air very slowly through the nose, and your enjoyment of a meal will be quintupled.
Obviously Kant made the mistake of his life when he said the sense of smell was not worth cultivating. It not only provides us with additional table pleasures, the hygienic and tonic value of which has been sufficiently dwelt upon, but it is a fact of unspeakable importance that the more we educate the nose, the more discriminating we make it, and the more stubbornly therefore we insist on having wholesome food only.