It is precisely in the so-called intelligent classes of Russians that a proper conception of life generally is often found wanting, and where an absolutely unphysiological indifference towards eating often exists. More methodical nations, like the English, have made a species of cult of the art of eating. It is, of course, degrading to indulge excessively and exclusively in culinary enjoyments, but, on the other hand, a lofty contempt for eating is also reprehensible. As so often is the case, the best course here also lies between the two extremes.

With the establishment of mental effect upon the secretion of juice the influence of condiments enters upon a new phase. The conclusion had already been empirically arrived at that it was not alone sufficient for the food to be composed exclusively of nutrient substances, but that it should also be tasty. Now, however, we know why this is so. For this reason the physician, who has often to express an opinion upon the suitability of the dietaries of different persons, or even of whole communities, should constantly bear in mind the question of psychic secretion; that is to say, he should inquire after and learn how the food has been eaten, whether with or without enjoyment But how often do the people who have charge of the commissariat pay attention solely to the nutritive value of the food, or place a higher value on everything else than taste? We must, further, in the interest of the public weal, direct attention especially to the feeding of children. If this or that inclination of the taste ultimately determines the relation of grown-up individuals towards food, a matter with which the commencing phase of digestion is closely linked, it would seem undesirable to habituate children solely to a nicety and uniformity of gustatory sensations.

Such might effect their capabilities of adapting themselves to other conditions in after life.

The question of the therapeutic influence of the so-called bitters, it appears to me, bears the closest connection with that of appetite. After a long period of high repute these substances have been almost expelled from the list of pharmaceutic remedies. When tested in the laboratory, they were unable to justify their old and valued reputation; when directly introduced into the stomach, many of them were unable to produce a flow of gastric juice. Consequently, in the eyes of the clinician, they became greatly discredited, so that many were quite ready to discard their use altogether. Obviously, the simple conclusion was drawn that a weak digestion could only be assisted by a remedy which directly excites secretory activity. In this, however, it was forgotten that the conditions of the experiment possibly had not corresponded with the actual state of affairs. The whole question of the therapeutic importance of the bitters, however, acquires a different significance when we link it with another question, such, for instance, as how do bitters affect the appetite? It is the universal opinion of the earlier and later physicians that bitters increase the appetite, and if this be so everything is said.

They are, in consequence, real secretory stimulants, since the appetite, as has many times been repeated in these lectures, is the strongest of all stimuli to the digestive glands. It is, however, not by any means strange that this had not previously been observed in the laboratory. The substances were either introduced directly into the stomachs of normal dogs or else injected into the circulation. But their action is chiefly bound up with their effect upon the gustatory nerves, and it was not, therefore, without some reason that this large group of remedies, consisting of substances of the most varied chemical composition, were grouped together mainly on account of a certain bitter taste common to them all. A person who suffers from digestive disturbance has, moreover, a blunted taste, a certain degree of gustatory indifference. The ordinary foods, which are agreeable to other people, and also to himself when in health, now appear tasteless. They not only arouse no desire for eating, but may even cause a feeling of dislike; there is no sense of taste, or at best a perverse one. It is necessary, therefore, that the gustatory apparatus should receive a strong stimulus in order to restore a normal sensation.

As experience teaches, this object is most quickly attained by exciting sharp, unpleasant, gustatory impressions, which by contrast awaken the idea of pleasant ones. In either case there is no longer indifference, and this is the foundation upon which an appetite for this or that kind of food may be awakened, and here a general physiological law is illustrated. The light appears brighter after darkness, a sound louder after silence, the enjoyment of blithesome health more intense after illness, and so on. This explanation of the appetising effects of bitters proceeding from the mouth does not exclude the possibility of some such similar influence coming also from the stomach. As has been already stated in the fifth lecture, there is some reason for believing that certain impulses from the cavity of the stomach are likewise necessary for the excitation of appetite. It is possible that bitters not only act directly on the gustatory nerves in the mouth, but that they also act on the mucous membrane of the stomach in such a way that sensations are generated which contribute to the passionate craving for food. As a matter of fact, it has been confirmed by many clinicians that after the administration of bitters some such special sensations do arise in the stomach.

The effect of these remedies consists, therefore, not merely in the generation of a simple reflex, but in the production of a certain psychic effect, which indirectly excites a physiological secretory activity. The same probably applies to other substances, such as condiments. In any case, whether our explanation corresponds to the actuality or not, the question of the therapeutic effect of bitters is settled in the affirmative the moment we acknowledge that these substances awaken appetite. The problem, therefore, of an experimental investigation of bitters consists in establishing the fact that they have an effect upon the appetite. The question is a difficult one, and has not hitherto been attempted in the laboratory. It is not sufficient to hand over clinical observations to the laboratory as experimental proofs. One must have, in addition, the assurance that the investigation has been correctly carried out; that is to say, that it dealt exactly with the point under consideration. It is interesting to observe that the connection between appetite and gastric juice is by many physicians, and in many text-books of medicine, exactly reversed.