Until my work began these two great sciences had been taught as distinct and separate branches of learning, while in reality _physiological chemistry_ is but half of a science, and _food chemistry_ is, in fact, the other half of the same science. The energy in food cannot be developed without the body--the body cannot develop energy without food. Each branch is worthless, therefore, without the other. In this work I have endeavored to unite them and to make of the two one practical, provable, and usable science. RELATION OF SUPERACIDITY TO OTHER DISEASES [Sidenote: Superacidity a primary cause] Nearly all stomach and intestinal troubles begin with superacidity. This is caused by the wrong combinations of food, or overeating. Food passing from the stomach, thus supercharged with acid, causes irritation of the mucous lining of the alimentary tract. This results in nervousness, insomnia, intestinal congestion (constipation), fermentation, and intestinal gas, while the excess of acid in the stomach causes irritation of the mucous surface of that much-abused organ, which develops first into catarrh, then ulceration, and sometimes into cancer. The accumulation of gas from the fermenting mass in the intestines causes irregular heart action, and sometimes heart failure. The great number of sudden deaths from this cause is pronounced by physicians "heart failure." In this the doctors and the writer agree--I know of no other way to die except for the heart to fail. The primary purpose of this work, however, is to ascertain _why_ the heart fails, and, if possible, to remove the causes. From the fermenting food toxic (poisonous) substances, such as carbon dioxid, are generated, which, when taken into the circulation, become a most prolific source of autointoxication (self-poisoning). From long experience gained by scientific feeding, in treating stomach and intestinal trouble, it became apparent that a great many disorders, very remote from the stomach, completely disappear when perfect digestion and assimilation of food, and thorough elimination of waste are effected. This has led to a very searching investigation of causes, and to the preparation of the following chart, which is designed to show how a great many so-called diseases can be traced back to one original cause--superacidity. [Illustration: CHART, SHOWING THE NUMBER OF SO CALLED DISEASES CAUSED BY SUPERACIDITY] [Sidenote: Power to resist disease depends upon correct feeding]