The physiological process of digestion is rather elaborate, and, fortunately for us, somewhat elastic. It is not a question entirely of certain substances in a test-tube exposed to certain digestive agents. This, of course, is the foundation, the basic process, but there is much variation in the nature of the food, in the external conditions of season, of heat and cold, of youth and age, of greater or less physical or mental demands on the food digested, and lastly on the supplies of saliva, of pepsin, of hydrochloric acid and of duodenal and pancreatic secretions. These are all under the control of the autonomous nervous system, which in the stresses of life often breaks down and fails to function properly. In the full tide of youthful energy our digestions seem to respond effectually to many and unreasonable demands, but this is more apparent than real; the bills may be a long time before they are sent in, but they come. The recuperative power of youth is marvellous, but probably never quite complete. After forty years of age it fails more and more, and then bills come in more quickly, while in old age it becomes almost a question of cash on delivery. Realizing this we should, in our own interests, treat our digestive apparatus with deep respect, and not with the scant courtesy we generally show, for on its faithful working depend our life, our health, our happiness and our powers of work. The farmer in his feeding of cattle, the head of a racing stable in his feeding and training of horses is far more scientific and wise than we and most other men are in the management of ourselves. This is why we end our days so often prematurely, or in paralysis and pain. To go into actual details of diet is a thankless task, and not very helpful to the mass of men; it is better, I think, to point out directions only. If there are symptoms of hyperpiesis, the chief object is to arrange a diet that contains a minimum of protein (especially of animal protein) compatible with life and energy. Most of such cases are leading a life of no great physical strain and will do well on a diet calculated in calories, that contains: Protein 90 Fat 75 Carbohydrate 330 = Calories 2,400. If this is insufficient, add to the fat or carbohydrate rather than to the protein. The following tables from Dr. Sprigg’s excellent work classify the common foods according as their energy production is due to protein, carbohydrate or fat. It will be noticed that milk is the only food in the lists which contains a good proportion of all three. Cheese, Brazil nuts and bread contain a fair proportion of at least two of the requisite food-stuffs. If we take, for instance, the figures of lean beef in the first and second column, viz.: Lean beef 90 + 10 we get its value Chicken 79 + 21 we get its value Bread 13 + 6 + 81 we get its value Cheese 25 + 73 + 2 we get its value