PROF. Pavlow does not limit his dietetic factors to the purely physiological field of individual digestion; he finds in mental attitudes a still stronger determination in the efficacy and specialty of human secretions. Any attempt of solving the problem of diet without due regard to the mental attitude of the individual is bound to fail. Thus what Dr. Pavlow calls the "desire element" in the appetite is the all-important factor which must be present with all successful digestion, as an opening agency for the initial gastric secretions. With a duration of from five to ten minutes this agency exerts an all powerful influence over the vagus nerve whose subsequent excitation at the second stage of the gastric secretion, is entirely determined by this initial impulse. Hence it is natural that any strong emotion of the individual at the time when he partakes of his meal, exerts the greatest influence either for good or bad over the ensuing process of digestion. For in the wake of the first or psychic stage of the digestive movements, with an intermission of some thirty or forty minutes, comes its second or specific stage, which arises in consequence of the stimulation from the entrance into the stomach of the different kinds of food. In other words, while the first stage of digestion is subject to the "psychic" influence, due to individual emotions, and consequently may be made to change the entire nature of its secretions by and through the conditions of the mind, the second stage of digestion is determined by the integral character of the food itself, and hence depends for its composition and efficacy on the mixtures indulged in by the individual in the course of his meal.

On the basis of these observations it is quite possible to work out a constructive system of diet, by which all ingrediencies can be eliminated from the meals which might chemically interfere with the normal workings of digestion. The elements which according to Prof. Pavlow especially interfere with the digestive process are not the so-called "mucous-bearing" foods, but the fats, grease, soda, acids, sugar and the pungent extractives which have a place in modern cookery. Furthermore, we find that an abnormal temperature of the food, either in excessive heat or excessive cold, interferes with the efficacy of secretions, while any distinct acidity such as vinegar, pickles or lemon juice, mixed with the food, acts as a severe check on the hydrochloric secretion. For while lemon juice while taken by itself, is of the greatest value as a uric acid and bile acid solvent, when taken in connection with food, not only loses its therapeutic value, but becomes a positive menace to digestion, and by introducing adverse chemical processes in the glandular secretions may give rise to the very bacterial acids which in its free state it would have destroyed. And on the same principle as acids, taken with foods, interfere with the hydrochloric acid in the stomach, so on the other hand the presence of sodium or any other hy-droxyl interferes with the pepsin secretions ; while fats and greases act as a powerful deterrent both upon the hydrochloric and pepsin secretions, and capable of lowering the entire digestive tone more than 50 per cent.

But if a right combination of foods is important for a successful digestion, the right temperature of the food is not less so. Beverages or soups connected with meals should not rise above the temperature of the body. In this connection Dr. Thompson, in his exhaustive treatise on "The Action of the Digestive Glands," has demonstrated with great clearness that digestion is seriously disturbed by either hot or ice cold beverages indulged in at meals. The life of the secretory glands is at its highest power when working in a temperature conforming to that of the body itself or at least not exceeding in warmth 105 degrees Fahrenheit. For through the influence of hot beverages the capillaries of the stomach dilate, causing an influx of blood into the stomach in excess of its need. And in the life of every organism we find that every degree of temperature, and every atom of energy, in excess of actual need - so far from aiding the individual, becomes a positive hindrance to his evolution. Stimulation beyond the capacity of the glands to utilize the increased supply, becomes an irritation followed by the inevitable reaction of a corresponding lowering of the vital tone of the organism.

The usual gastric stimulants or "appetizers" for the table, as furnished by our condiments, spices, pickles, preserves, conserves; cured, candied, smoked and deviled food-preparations, have no other value than irritants, with power to whip the stomach into digestive spasms. Their action on the stomach is that of a lash, as the very fact of their indigestibility compels the system to furnish an extra supply of nervous energy to reenforce the exhausted digestive batteries, And it is this rush of released nervous reserve force, sweeping through the digestive field, that gives rise to sensations of heightened digestive and assimilative powers.