Just as in this case the fixed idea that bad air (malaria) must be responsible for the disease obscured the truth, so the undeserved homage bestowed on the sense of taste blinded those who wrote on this subject, including Brillat-Savarin.
In his "Physiology of Taste" he has a chapter on the senses in which he beats around the bush in the most ridiculous way. He knew that if you have a cold, or hold your nose while eating, "no flavor is perceived in anything that is swallowed"; yet from this he inferred that "all sense of taste is obliterated," although the simplest experiment would have shown him that a cold does not affect the sensations of sweet, sour, salt, bitter, alkaline, or metallic in the least; and after several pages of argumentation he comes to the absurd conclusion that "there is no complete perception of taste unless the sense of smell have a share in the sensation," and that, in fact, "smell and taste form only one sense, having the mouth as laboratory with the nose for fireplace or chimney." You might as well say that sight and hearing form only one sense.
Dr. Charles Henry Piesse, member of the Royal College of Surgeons, is another author who came within half an inch of the truth, yet missed it. He wrote a little volume, "Olfactics and the Physical Senses," which is full of interesting facts and suggestions. Two citations, the first from "The Art of Perfumery," written by Dr. Piesse's father, the second from "Olfactics," will show "how warm" these two men got in their search, as the children say in their play.
To the unlearned nose all odors are alike; but when tutored, either for pleasure or profit, no member of the body is more sensitive. Wine merchants, tea brokers, drug dealers, tobacco importers, and many others, have to go through a regular educational nasal course. A hop merchant buries his nose in a pocket, takes a sniff, and then sets his price upon the bitter flower.
The odors have to be remembered, and it is noteworthy here to remark with what persistence odors do fix themselves upon the memory; and were it not for this remembrance of an odor, the merchants in the trades above indicated would soon be at fault. An experienced perfumer will have two hundred odors in his laboratory, and can distinguish every one by name.
When the breath is held the most odorous substances may be spread in the interior of the nostrils without their perfume being perceived. This observation was first made by Galen. It has been frequently remarked that odors are smelt only during inspiration; the same air, when returned through the nostrils, always proving inodorous. But this is true only when the odor has been admitted from without by the nostrils, for when it is admitted by the mouth, as in combination with articles of nutrition, it can be perceived during expiration through the nose.
Yet this man, who thus came so near the truth, missed it as widely as all the others! Throughout his books he talks as if taste were "it." The number of "different tastes, or flavors" is, "of course, unlimited," he says; whereas, let me say it once more, there are only six tastes: sweet, salt, sour, bitter, metallic and alkaline. Again, he remarks that "the importance of possessing a pure and cultivated sense of taste is very great in certain trades and professions, as, for instance, the occupation of a wine-taster, a tea-taster, a coffee-taster. These persons are all gourmets; the word gourmet signifying a taster." Wrong, from beginning to end. Coffee, tea, and wine "tasters"—the men who sample these articles to adjudge their commercial value—are guided entirely by their Flavor, that is, their appeal to the sense of smell; while epicures owe nine-tenths of their enjoyment of food to that sense and only one-tenth to the sense of taste.
Even Professor Dr. Gustav Jäger, the famous apostle of "all-wool for man's wear," missed the mark. He wrote a book, "Die Entdeckung der Seele," in which he tried to prove that smell is really the most important of our senses, the olfactory nerve being in fact the seat of the soul! Yet this ardent advocate entirely failed to see the truth I have set forth in this book—the fact that to the sense of smell we owe most of the countless pleasures of the table, with all their important digestive and hygienic consequences. Just like all the other misguided writers on this subject, he speaks of differences in taste between lobster and crawfish, or between the eggs of hens, ducks, geese, and so on, although it is the nose and not the tongue that enables us to tell them apart.
HOW FLAVOR DIFFERS FROM FRAGRANCE.
Throughout this volume I have used the word Flavor as if it were virtually synonymous with odor, fragrance, aroma. Strictly speaking, it is not, for taste usually enters as an ingredient; but from a gastronomic point of view the taste is usually so subordinate that it is almost negligible. To say it once more, we hardly enjoy vinegar unless it is fragrant, and while we like the taste of sugar we gladly pay from five to thirty times as much for it when it is flavored and sold as candy.
In the great Oxford Dictionary two definitions of the word flavor are given. It means, in the best literary usage, either a smell, odor, aroma, pure and simple; or it means "the element in the taste of a substance which depends on the coöperation of the sense of smell."
If asked for my own definition I should say that "flavor is the odor of a substance as perceived in breathing out through the nose while we are eating, and usually accompanied by a sweet, sour, salt, or bitter taste." This distinguishes flavor from fragrance, which we perceive in breathing in through the nose; as, the fragrance of a rose or a violet—and this is not accompanied by a taste.