Eclectic Magazine of Foreign Literature, Science, and Art, February, 1885

Taste, however, is not equally distributed over the whole surface of the tongue alike. There are three distinct regions or tracts, each of which has to perform its own special office and function. The tip of the tongue is concerned mainly with pungent and acrid tastes; the middle portion is sensitive chiefly to sweets and bitters; while the back or lower portion confines itself almost entirely to the flavors of roast meats, butter, oils, and other rich or fatty substances. There are very good reasons for this subdivision of faculties in the tongue, the object being, as it were, to make each piece of food undergo three separate examinations (like “smalls,” “mods,” and “greats” at Oxford), which must be successively passed before it is admitted into full participation in the human economy. The first examination, as we shall shortly see, gets rid at once of substances which would be actively and immediately destructive to the very tissues of the mouth and body; the second discriminates between poisonous and chemically harmless foodstuffs; and the third merely decides the minor question whether the particular food is likely to prove then and there wholesome or indigestible to the particular person. The sense of taste proceeds, in fact, upon the principle of gradual selection and elimination; it refuses first what is positively destructive, next what is more remotely deleterious, and finally what is only undesirable or over-luscious.

When we want to assure ourselves, by means of taste, about an unknown object – say a lump of some white stuff, which may be crystal, or glass, or alum, or borax, or quartz, or rocksalt – we put the tip of the tongue against it gingerly. If it begins to burn us, we draw it away more or less rapidly, with an accompaniment in language strictly dependent upon our personal habits and manners. The test we thus occasionally apply, even in the civilised adult state, to unknown bodies is one that is being applied every day and all day long by children and savages. Unsophisticated humanity is constantly putting everything it sees up to its mouth in a frank spirit of experimental inquiry as to its gustatory properties. In civilised life, we find everything ready labelled and assorted for us; we comparatively seldom require to roll the contents of a suspicious bottle (in very small quantities) doubtfully upon the tongue in order to discover whether it is pale sherry or Chili vinegar, Dublin stout or mushroom ketchup. But in the savage state, from which, geologically and biologically speaking, we have only just emerged, bottles and labels do not exist. Primitive man, therefore, in his sweet simplicity, has only two modes open before him for deciding whether the things he finds are or are not strictly edible. The first thing he does is to sniff at them, and smell being, as Mr. Herbert Spencer has well put it, an anticipatory taste, generally gives him some idea of what the thing is likely to prove. The second thing he does is to pop it into his mouth, and proceed practically to examine its further characteristics.

Strictly speaking with the tip of the tongue one can’t really taste at all. If you put a small drop of honey or of oil of bitter almonds on that part of the mouth, you will find (no doubt to your great surprise) that it produces no effect of any sort; you only taste it when it begins slowly to diffuse itself, and reaches the true tasting region in the middle distance. But if you put a little cayenne or mustard on the same part, you will find that it bites you immediately – the experiment should be tried sparingly – while, if you put it lower down in the mouth you will swallow it almost without noticing the pungency of the stimulant. The reason is, that the tip of the tongue is supplied only with nerves which are really nerves of touch, not nerves of taste proper; they belong to a totally different main branch, and they go to a different centre in the brain, together with the very similar threads which supply the nerves of smell for mustard and pepper. That is why the smell and taste of these pungent substances are so much alike, as everybody must have noticed; a good sniff at a mustard-pot producing almost the same irritating effects as an incautious mouthful. As a rule, we don’t accurately distinguish, it is true, between these different regions of taste in the mouth in ordinary life; but that is because we usually roll our food about instinctively, without paying much attention to the particular part affected by it. Indeed, when one is trying deliberate experiments in the subject, in order to test the varying sensitiveness of the different parts to different substances, it is necessary to keep the tongue quite dry, in order to isolate the thing you are experimenting with, and prevent its spreading to all parts of the mouth together. In actual practice this result is obtained in a rather ludicrous manner – by blowing upon the tongue, between each experiment, with a pair of bellows. To such undignified expedients does the pursuit of science lead the ardent modern psychologist. These domestic rivals of Dr. Forbes Winslow, the servants, who behold the enthusiastic investigator alternately drying his tongue in this ridiculous fashion, as if he were a blacksmith’s fire, and then squeezing out a single drop of essence of pepper, vinegar, or beef-tea from a glass syringe upon the dry surface, not unnaturally arrive at the conclusion that master has gone stark mad, and that, in their private opinion, it’s the microscope and the skeleton as has done it.

Above all things, we don’t want to be flayed alive. So the kinds of tastes discriminated by the tip of the tongue are the pungent, like pepper, cayenne, and mustard; the astringent, like borax and alum; the alkaline, like soda and potash; the acid, like vinegar and green fruit; and the saline, like salt and ammonia. Almost all the bodies likely to give rise to such tastes (or, more correctly, sensations of touch in the tongue) are obviously unwholesome and destructive in their character, at least when taken in large quantities. Nobody wishes to drink nitric acid by the quart. The first business of this part of the tongue is, therefore, to warn us emphatically against caustic substances and corrosive acids – against vitriol and kerosene, spirits of wine and ether, capsicums and burning leaves or roots, such as those of the common English lords-and-ladies. Things of this sort are immediately destructive to the very tissues of the tongue and palate; if taken incautiously in too large doses, they burn the skin off the roof of the mouth; and when swallowed they play havoc, of course, with our internal arrangements. It is highly advisable, therefore, to have an immediate warning of these extremely dangerous substances, at the very outset of our feeding apparatus.

This kind of taste hardly differs from touch or burning. The sensibility of the tip of the tongue is only a very slight modification of the sensibility possessed by the skin generally, and especially by the inner folds over all delicate parts of the body. We all know that common caustic burns us wherever it touches; and it burns the tongue, only in a somewhat more marked manner. Nitric or sulphuric acid attacks the fingers each after its own kind. A mustard plaster makes us tingle almost immediately; and the action of mustard on the tongue hardly differs, except in being more instantaneous and more discriminative. Cantharides work in just the same way. If you cut a red pepper in two and rub it on your neck it will sting you just as it does when put into soup (this experiment, however, is best tried upon one’s younger brother; if made personally, it hardly repays the trouble and annoyance). Even vinegar and other acids, rubbed into the skin, are followed by a slight tingling; while the effect of brandy, applied, say, to the arms, is gently stimulating and pleasurable, somewhat in the same way as when normally swallowed in conjunction with the habitual seltzer. In short, most things which give rise to distinct tastes when applied to the tip of the tongue, give rise to fainter sensations when applied to the skin generally. And one hardly needs to be reminded that pepper or vinegar placed (accidentally as a rule) on the inner surface of the eyelids produces a very distinct and unpleasant smart.

The fact is, the liability to be chemically affected by pungent or acid bodies is common to every part of the skin; but it is least felt where the tough outer skin is thickest, and most felt where that skin is thinnest, and the nerves are most plentifully distributed near the surface. A mustard plaster would probably fail to draw at all on one’s heel or the palm of one’s hand; while it is decidedly painful on one’s neck or chest; and a mere speck of mustard inside the eyelid gives one positive torture for hours together. Now the tip of the tongue is just a part of one’s body specially set aside for this very object, provided with an extremely thin skin, and supplied with an immense number of nerves, on purpose so as to be easily affected by all such pungent, alkaline, or spirituous substances. Sir Wilfrid Lawson would probably conclude that it was deliberately designed by Providence to warn us against a wicked indulgence in the brandy and seltzer aforesaid.

At first sight it might seem as though there were hardly enough of such pungent and fiery things in existence to make it worth while for us to be provided with a special mechanism for guarding against them. That is true enough, no doubt, as regards our modern civilized life; though, even now, it is perhaps just as well that our children should have an internal monitor (other than conscience) to dissuade them immediately from indiscriminate indulgence in photographic chemicals, the contents of stray medicine bottles, and the best dried West India chilies. But in an earlier period of progress, and especially in tropical countries (where the Darwinians have now decided the human race made its first début upon this or any other stage), things were very different indeed. Pungent and poisonous plants and fruits abounded on every side. We have all of us in our youth been taken in by some too cruelly waggish companion, who insisted upon making us eat the bright, glossy leaves of the common English arum, which without look pretty and juicy enough, but within are full of the concentrated essence of pungency and profanity. Well, there are hundreds of such plants, even in cold climates, to tempt the eyes and poison the veins of unsuspecting cattle or childish humanity. There is buttercup, so horribly acrid that cows carefully avoid it in their closest cropped pastures; and yet your cow is not usually a too dainty animal. There is aconite, the deadly poison with which Dr. Lamson removed his troublesome relatives. There is baneberry, whose very name sufficiently describes its dangerous nature. There are horseradish, and stinging rocket, and biting wall-pepper, and still smarter water-pepper, and wormwood, and nightshade, and spurge, and hemlock, and half a dozen equally unpleasant weeds. All of these have acquired their pungent and poisonous properties, just as nettles have acquired their sting, and thistles their thorns, in order to prevent animals from browsing upon them and destroying them. And the animals in turn have acquired a very delicate sense of pungency on purpose to warn them beforehand of the existence of such dangerous and undesirable qualities in the plants which they might otherwise be tempted incautiously to swallow.

In tropical woods, where our “hairy quadrumanous ancestor” (Darwinian for the primæval monkey, from whom we are presumably descended) used playfully to disport himself, as yet unconscious of his glorious destiny as the remote progenitor of Shakespeare, Milton, and the late Mr. Peace – in tropical woods, such acid or pungent fruits and plants are particularly common, and correspondingly annoying. The fact is, our primitive forefather and all the other monkeys are, or were, confirmed fruit-eaters. But to guard against their depredations a vast number of tropical fruits and nuts have acquired disagreeable or fiery rinds and shells, which suffice to deter the bold aggressor. It may not be nice to get your tongue burnt with a root or fruit, but it is at least a great deal better than getting poisoned; and, roughly speaking, pungency in external nature exactly answers to the rough gaudy labels which some chemists paste on bottles containing poisons. It means to say, “This fruit or leaf, if you eat it in any quantities, will kill you.” That is the true explanation of capsicums, pimento, colocynth, croton oil, the upas tree, and the vast majority of bitter, acrid, or fiery fruits and leaves. If we had to pick up our own livelihood, as our naked ancestors had to do, from roots, seeds, and berries, we should far more readily appreciate this simple truth. We should know that a great many more plants than we now suspect are bitter or pungent, and therefore poisonous. Even in England we are familiar enough with such defences as those possessed by the outer rind of the walnut; but the tropical cashewnut has a rind so intensely acrid that it blisters the lips and fingers instantaneously, in the same way as cantharides would do. I believe that on the whole, taking nature throughout, more fruits and nuts are poisonous, or intensely bitter, or very fiery, than are sweet, luscious, and edible.

“But,” says that fidgety person, the hypothetical objector (whom one always sets up for the express purpose of promptly knocking him down again), “if it be the business of the forepart of the tongue to warn us against pungent and acrid substances, how comes it that we purposely use such things as mustard, pepper, curry-powder, and vinegar?” Well, in themselves all these things are, strictly speaking, bad for us; but in small quantities they act as agreeable stimulants; and we take care in preparing most of them to get rid of the most objectionable properties. Moreover, we use them, not as foods, but merely as condiments. One drop of oil of capsicum is enough to kill a man, if taken undiluted; but in actual practice we buy it in such a very diluted form that comparatively little harm arises from using it. Still, very young children dislike all these violent stimulants, even in small quantities; they won’t touch mustard, pepper, or vinegar, and they recoil at once from wine or spirits. It is only by slow degrees that we learn these unnatural tastes, as our nerves get blunted and our palates jaded; and we all know that the old Indian who can eat nothing but dry curries, devilled biscuits, anchovy paste, pepper-pot, mulligatawny soup, Worcestershire sauce, preserved ginger, hot pickles, fiery sherry, and neat cognac, is also a person with no digestion, a fragmentary liver, and very little chance of getting himself accepted by any safe and solvent insurance office. Throughout, the warning in itself is a useful one; it is we who foolishly and persistently disregard it. Alcohol, for example, tells us at once that it is bad for us; yet we manage so to dress it up with flavoring matters and dilute it with water that we overlook the fiery character of the spirit itself. But that alcohol is in itself a bad thing (when freely indulged in) has been so abundantly demonstrated in the history of mankind that it hardly needs any further proof.

The middle region of the tongue is the part with which we experience sensations of taste proper – that is to say, of sweetness and bitterness. In a healthy, natural state all sweet things are pleasant to us, and all bitters (even if combined with sherry) unpleasant. The reason for this is easy enough to understand. It carries us back at once into those primæval tropical forests where our “hairy ancestor” used to diet himself upon the fruits of the earth in due season. Now, almost all edible fruits, roots, and tubers contain sugar; and therefore the presence of sugar is, in the wild condition, as good a rough test of whether anything is good to eat as one could easily find. In fact, the argument cuts both ways: edible fruits are sweet because they are intended for man and other animals to eat; and man and other animals have a tongue pleasurably affected by sugar because sugary things in nature are for them in the highest degree edible. Our early progenitors formed their taste upon oranges, mangoes, bananas, and grapes; upon sweet potatoes, sugar-cane, dates, and wild-honey. There is scarcely anything fitted for human food in the vegetable world (and our earliest ancestors were most undoubted vegetarians), which does not contain sugar in considerable quantities. In temperate climates (where man is but a recent intruder), we have taken, it is true, to regarding wheaten bread as the staff of life; but in our native tropics enormous populations still live almost exclusively upon plantains, bananas, breadfruit, yams, sweet potatoes, dates, cocoanuts, melons, cassava, pineapples, and figs. Our nerves have been adapted to the circumstances of our early life as a race in tropical forests; and we still retain a marked liking for sweets of every sort. Not content with our strawberries, raspberries, gooseberries, currants, apples, pears, cherries, plums, and other northern fruits, we ransack the world for dates, figs, raisins, and oranges. Indeed, in spite of our acquired meat-eating propensities, it may be fairly said that fruits and seeds (including wheat, rice, peas, beans, and other grains and pulse) still form by far the most important element in the foodstuffs of human populations generally.

But besides the natural sweets, we have also taken to producing artificial ones. Has any housewife ever realised the alarming condition of cookery in the benighted generations before the invention of sugar? It is really almost too appalling to think about. So many things that we now look upon as all but necessaries – cakes, puddings, made dishes, confectionery, preserves, sweet biscuits, jellies, cooked fruits, tarts, and so forth – were then practically quite impossible. Fancy attempting nowadays to live a single day without sugar; no tea, no coffee, no jam, no pudding, no cake, no sweets, no hot toddy before one goes to bed; the bare idea of it is too terrible. And yet that was really the abject condition of all the civilised world up to the middle ages. Horace’s punch was sugarless and lemonless; the gentle Virgil never tasted the congenial cup of afternoon tea; and Socrates went from his cradle to his grave without ever knowing the flavor of peppermint bull’s eyes. How the children managed to spend their Saturday as, or their weekly obolus, is a profound mystery. To be sure, people had honey; but honey is rare, dear, and scanty; it can never have filled one quarter the place that sugar fills in our modern affections. Try for a moment to realise drinking honey with one’s whiskey-and-water, or doing the year’s preserving with a pot of best Narbonne, and you get at once a common measure of the difference between the two as practical sweeteners. Nowadays, we get sugar from cane and beetroot in abundance, while sugar-maples and palm-trees of various sorts afford a considerable supply to remoter countries. But the childhood of the little Greeks and Romans must have been absolutely unlighted by a single ray of joy from chocolate creams or Everton toffee.

The consequence of this excessive production of sweets in modern times is, of course, that we have begun to distrust the indications afforded us by the sense of taste in this particular as to the wholesomeness of various objects. We can mix sugar with anything we like, whether it had sugar in it to begin with or otherwise; and by sweetening and flavoring we can give a false palatableness to even the worst and most indigestible rubbish, such as plaster-of-Paris, largely sold under the name of sugared almonds to the ingenuous youth of two hemispheres. But in untouched nature the test rarely or never fails. As long as fruits are unripe and unfit for human food, they are green and sour; as soon as they ripen they become soft and sweet, and usually acquire some bright color as a sort of advertisement of their edibility. In the main, bar the accidents of civilisation, whatever is sweet is good to eat – nay more, is meant to be eaten; it is only our own perverse folly that makes us sometimes think all nice things bad for us, and all wholesome things nasty. In a state of nature, the exact opposite is really the case. One may observe, too, that children, who are literally young savages in more senses than one, stand nearer to the primitive feeling in this respect than grown-up people. They unaffectedly like sweets; adults, who have grown more accustomed to the artificial meat diet, don’t as a rule, care much for puddings, cakes, and made dishes. (May I venture parenthetically to add, any appearance to the contrary notwithstanding, that I am not a vegetarian, and that I am far from desiring to bring down upon my devoted head the imprecation pronounced against the rash person who would rob a poor man of his beer. It is quite possible to believe that vegetarianism was the starting-point of the race, without wishing to consider it also as the goal; just as it is quite possible to regard clothes as purely artificial products of civilization, without desiring personally to return to the charming simplicity of the Garden of Eden.)

Bitter things in nature at large, on the contrary, are almost invariably poisonous. Strychnia, for example, is intensely bitter, and it is well known that life cannot be supported on strychnia alone for more than a few hours. Again, colocynth and aloes are far from being wholesome food stuffs, for a continuance; and the bitter end of cucumber does not conduce to the highest standard of good living. The bitter matter in decaying apples is highly injurious when swallowed, which it isn’t likely to be by anybody who ever tastes it. Wormwood and walnut-shells contain other bitter and poisonous principles; absinthe, which is made from one of them, is a favorite slow poison with the fashionable young men of Paris, who wish to escape prematurely from “Le monde où l’on s’ennuie.” But prussic acid is the commonest component in all natural bitters, being found in bitter almonds, apple pippins, the kernels of mango-stones, and many other seeds and fruits. Indeed, one may say roughly that the object of nature generally is to prevent the actual seeds of edible fruits from being eaten and digested; and for this purpose, while she stores the pulp with sweet juices, she encloses the seed itself in hard stony coverings, and makes it nasty with bitter essences. Eat an orange pip, and you will promptly observe how effectual is this arrangement. As a rule, the outer rind of nuts is bitter, and the inner kernel of edible fruits. The tongue thus warns us immediately against bitter things, as being poisonous, and prevents us, automatically, from swallowing them.

“But how is it,” asks our objector again, “that so many poisons are tasteless, or even, like sugar of lead, pleasant to the palate?” The answer is (you see, we knock him down again, as usual) because these poisons are themselves for the most part artificial products; they do not occur in a state of nature, at least in man’s ordinary surroundings. Almost every poisonous thing that we are really liable to meet with in the wild state we are warned against at once by the sense of taste; but of course it would be absurd to suppose that natural selection could have produced a mode of warning us against poisons which have never before occurred in human experience. One might just as well expect that it should have rendered us dynamite-proof, or have given us a skin like the hide of a rhinoceros to protect us against the future contingency of the invention of rifles.

Sweets and bitters are really almost the only tastes proper, almost the only ones discriminated by this central and truly gustatory region of the tongue and palate. Most so-called flavorings will be found on strict examination to be nothing more than mixtures with these of certain smells or else of pungent, salty, or alkaline matters, distinguished as such by the tip of the tongue. For instance, paradoxical as it sounds to say so, cinnamon has really no taste at all, but only a smell. Nobody will ever believe this on first hearing, but nothing on earth is easier than to put it to the test. Take a small piece of cinnamon, hold your nose tightly, rather high up, between the thumb and finger, and begin chewing it. You will find that it is absolutely tasteless; you are merely chewing a perfectly insipid bit of bark. Then let go your nose, and you will find immediately that it “tastes” strongly, though in reality it is only the perfume from it that you now permit to rise into the smelling-chamber in the nose. So, again, cloves have only a pungent taste and a peculiar smell, and the same is the case more or less with almost all distinctive flavorings. When you come to find of what they are made up, they consist generally of sweets or bitters, intermixed with certain ethereal perfumes, or with pungent or acid tastes, or with both or several such together. In this way, a comparatively small number of original elements, variously combined, suffice to make up the whole enormous mass of recognisably different tastes and flavors.