We are, as yet, far from an exact endocrine analysis of the individual. But we know that the endocrines rule over growth and nutrition, a vast dominion which incorporates every organ and every tissue. By enhancing or retarding the nutritional changes, the growth of the organ or tissue is favored or restricted. The size and shape of an individual, as a whole, as well as of the specialized cell masses composing him, as hands and feet, the nose and ears, and so on, are therefore controlled by them. Whether an organism is to be tall or short, lean or corpulent, graceful or awkward, is decided by their interactions. These, like human covenants, vary with the different reactions of the parties to the contract. And so a great deal depends upon whether they work harmoniously or discordantly, and upon which does the most work and which the least. Undersecretion and Oversecretion It is when a gland, either in the course of development, or because of the influence of starvation, shock, injury, poisoning or infection, begins to undersecrete or oversecrete that its effects upon growth and nutrition become grossly manifest. A veritable transfiguration of the individual may occur, the black magic of which may perplex him for a lifetime. A man, made eunuchoid by an accident or by mumps, will observe in himself astonishing changes in his constitutional make-up, mentality and sexuality. He would be more astounded to learn that beneath the appearances, the changes, so alarming him, there are profound alterations in the rate at which he is taking in oxygen, burning up sugar, accumulating carbon dioxide and excreting waste byproducts through the kidneys, which are responsible for them. The differences between the normal and abnormal are only a matter of degree. And so, to be sure, are differences between types. But it is hard to realize that the striking distinctions between the thyroid type and the pituitary, comparable, as said, to the differences between a greyhound and a bull-dog, are dependent solely upon quantitative variations in the general and local speeds of metabolism, among the cells. DIVISION OF LABOR