The Physiology of Taste (13 page)

Such is the destiny of man, considered as a sentient being: it is to this double end that all his actions lead.

His eyes perceive exterior objects, reveal to him the wonders that surround him, and teach him that he is but part of a great whole.

His hearing catches the sounds about him, not only as a pleasant sensation, but also as an intimation of the movements of other bodies which may mean danger to him.

Feeling stands guard to warn him, by means of pain, that he has been hurt.

His hands, those faithful servants, not only help him to protect himself and to stand upright, but by preference they curve themselves around those objects which his instinct tells him are the right ones to repair the damages which have been caused him by his struggle to survive.

His sense of smell next explores these objects, for harmful substances almost always have a stench.

Finally taste asserts itself, man’s teeth come into action, his tongue and palate unite to enjoy the flavor of what he eats, and soon his stomach begins to assimilate the meal.

In this state an unfamiliar languor creeps over him, objects fade, his body grows limp, his eyes close; everything disappears, and his senses fall into a complete repose.

When he awakens, he sees that nothing around him has changed; however, a secret fire burns in his breast, a new organ has been developed; he feels that now he must share his life with someone.

This active, troubling, imperious sentiment is common to both sexes; it brings them together and unites them, and when the germ of a new life has been fertilized, the two people can sleep again in peace; they have fulfilled the most sacred of their duties in thus making sure that mankind will continue.
^*

Such are the conclusions, general and philosophical, which I have felt I should offer to my readers, to lead them easily into the more detailed examination of the sense of taste.

6:
TASTE
IS
THE
sense which puts us in contact with savorous or sapid bodies, by means of the sensation which they cause in the organ destined to appreciate them.

This sense, which can be excited by appetite, hunger, and thirst, is the basis for several operations which result in a man’s growth and development, in his self-preservation, and in the general repairs to his body of the losses caused by elimination and evaporation.

All organized species of existence do not nourish themselves in the same way; the Creator, as varied in his methods as he is sure in his results, has given to each form of life a different way of conserving itself.

Plants, at the bottom of the scale, feed themselves through their roots, which, embedded in the earth, choose by means of their own peculiar mechanism the various substances which will make them grow and flourish.

A little higher up the scale we find those creatures which, although they are blessed with animal life, are still deprived of the power of moving about. They are born into surroundings which favor their existence, and from which their special organs extract whatever they need to last their apportioned spans of life. They do not look for their nourishment, but rather it seeks them out.

Another way has been arranged for the creatures who roam the world, of whom man is without doubt the most highly developed. An instinct peculiar to him warns him when he must eat; he looks for food; he seizes whatever he suspects will satisfy
him; then he eats, feels strong again, and goes on through his whole life in this pattern which has been set.

Taste can be considered under three different headings:

    In physical man it is the apparatus by which he distinguishes various flavors.

In moral man it is the sensation which stimulates that organ in the center of his feeling which is influenced by any savorous body.

Lastly, in its own material significance, taste is the property possessed by any given substance which can influence the organ and give birth to sensation.

    Taste seems to possess two main functions.

    (1) It invites us, by arousing our pleasure, to repair the constant losses which we suffer through our physical existence.

(2) It helps us to choose from the variety of substances which Nature presents to us those which are best adapted to nourish us.

    In this choice, taste is greatly helped by the sense of smell, as we shall see later; it can be established as a general maxim that nourishing things are not repulsive to either sense.

7: It is not easy to determine precisely what parts make up the organ of taste. It is more complicated than it seems.

Certainly, the tongue plays an important role in the mechanics of tasting: endowed as it is with a fairly powerful muscular force, it helps to moisten, mash, churn about, and swallow the food.

Moreover, by means of the varying numbers of papillae which protude like tiny buds from its surface, it saturates itself with the tasteful and soluble particles of whatever body it is in contact with; this, however, is not enough, and several other adjacent parts of the mouth work together to complete the sensation: the insides of the cheeks, the roof of the mouth, and above all the nasal channel, upon whose importance the physiologists have perhaps not insisted strongly enough.

The inside cheeks furnish saliva, which is equally necessary to
the act of chewing and to making the food of such a consistency as can be swallowed; they are, like the palate or roof of the mouth, gifted with their share of enjoyment, and I do not even know whether, in certain cases, the gums themselves may not share somewhat in this appreciation; while without that final savoring which takes place at the back of the tongue, the whole sensation of taste would be obscure and quite incomplete.

Anyone who has been born without a tongue, or whose tongue has been cut out, still has a moderately strong sense of taste. The first instance can often be found in literature; the second has been fairly well described to me by a poor devil whose tongue had been amputated by the Algerians, to punish him for having plotted with one of his fellow prisoners to break out and flee.

This man, whom I met in Amsterdam, where he made his living by running errands, had had some education, and it was easy to communicate with him by writing.

After I had observed that the forepart of his tongue had been cut off clear to the ligament, I asked him if he still found any flavor in what he ate, and if his sense of taste had survived the cruelty to which he had been subjected.

He replied that what tired him most was to swallow (which he could not do without some difficulty); that he still possessed the ability to taste fairly well; that he could tell, with other more normal men, what was pleasant or unappetizing; but that very sour or bitter things caused him unbearable pain.

He also told me that the amputation of tongues was common in African kingdoms, that it was performed especially on men believed to be the ringleaders in any plots, and that there were appropriate instruments for it. I should have liked him to describe the operation to me, but he showed at this point such misery and revulsion that I did not insist on it.

I thought about what he had told me; and turning back to the days of ignorance when we used to pierce and cut out the tongues of religious blasphemers, and to the period in history when such laws were made, I felt that I was right in concluding that they were of African origin, brought back to Europe by the Crusaders.

I have already stated that the sense of taste resides mainly in the papillae of the tongue. Now the study of anatomy teaches us
that all tongues are not equally endowed with these taste buds, so that some may possess even three times as many of them as others. This circumstance explains why, of two diners seated at the same feast, one is delightfully affected by it, while the other seems almost to force himself to eat: the latter has a tongue but thinly provided with papillae, which proves that the empire of taste may also have its blind and its deaf subjects.

8: Five or six opinions have been broached by now on the way in which the sensation of taste functions; I have my own personal one, and here it is:

This sensation is a chemical operation which is accomplished, as we have already remarked, by moisture. That is to say, the sapid molecules must be dissolved in no matter what kind of fluid, so that they may then be absorbed by the sensitive projections, buds, or suckers which line the interior of the apparatus for tasting.

This theory, whether new or not, is supported by physical and almost palpable proofs.
¹

Pure water awakens no sensation of taste, because it contains no sapid bodies. But dissolve a pinch of salt in it, or add a few drops of vinegar, and the sensation will occur.

Other drinks, however, impress our taste sense because they are nothing more nor less than solutions charged in varying degrees with appreciable particles.

In vain might the mouth be filled with separate morsels of an insoluble body: the tongue would experience the sensation of touch, but never of taste.

As for flavorsome and solid bodies, the teeth must cut them up, saliva and the other taste fluids must soak them, and the tongue must roll them against the palate so that they exude a juice which, by now sufficiently sapid, is appreciated by the taste buds which in turn give to the mashed food that passport it needs to be admitted to the human stomach.

This theory, which will be developed even further, easily answers the main questions that can arise.

If it is asked what I mean by the word sapid, I reply that it is anything which is soluble and which can be absorbed by the taste buds.

And if it is asked how a sapid body acts, I reply that it acts whenever it finds itself in such a state of dissolution that it can penetrate the cavities meant to receive and transmit taste.

In a word, nothing is sapid which is not either already dissolved, or easily soluble.

9: The number of tastes is infinite, since every soluble body has a special flavor which does not wholly resemble any other.

Tastes are modified, moreover, by their combinations with one, two, or a dozen others, so that it is impossible to draw up a correct chart, listing them from the most attractive to the most repellent, from the strawberry to the griping bitter apple. Anyone who has ever attempted this has of course failed.

This is not astonishing, for given the fact that there exists an indefinite series of simple tastes which can change according to the number and variety of their combinations, we should need a whole new language to describe all these effects, and mountains of folio foolscap to define them, and unknown numerical characters for their classification.

Up to the present time there is not a single circumstance in which a given taste has been analyzed with stern exactitude, so that we have been forced to depend on a small number of generalizations such as
sweet, sugary, sour, bitter
, and other like ones which express, in the end, no more than the words
agreeable
or
disagreeable
, and are enough to make themselves understood and to indicate, more or less, the taste properties of the sapid body which they describe.

Men who will come after us will know much more than we of this subject; and it cannot be disputed that it is chemistry which will reveal the causes or the basic elements of taste.

10: The pattern which I have set for myself has unwittingly led me to the point where I must concede all due rights to the sense of smell, and must recognize the important services which it renders to us in our appreciation of tastes; for, among the authors whose books I have read, I have found not one who seems to me to have paid it full and complete justice.

For myself, I am not only convinced that there is no full act of tasting without the participation of the sense of smell, but I am also tempted to believe that smell and taste form a single sense, of which the mouth is the laboratory and the nose is the chimney; or, to speak more exactly, of which one serves for the tasting of actual bodies and the other for the savoring of their gases.

This theory can be strikingly supported; however, since I have no desire to set up my own school, I mention it only to give my readers food for thought, and to show that I have studied my subject at first hand. Therefore I shall now continue my exposition of the importance of smell, at least as a necessary aid to taste if not as an integral part of it.

Any sapid body is perforce odorous, which places it in the realm of the sense of smell as well as in that of taste.

A man eats nothing without smelling it more or less consciously, while with unknown foods his nose acts always as the first sentinel, crying out
Who goes there?

When the sense of smell is cut off, taste itself is paralyzed, as can be proved by three experiments which anyone may perform with equal success.

First experiment:
When the nasal membrane is irritated by a violent
coryza
(head cold), taste is completely wiped out: there is absolutely no flavor in anything one swallows, in spite of the fact that the tongue continues to be in its normal state.