If a single gland can dominate the life history of an individual it becomes possible to speak of _endocrine types_, the result of the _endocrine analysis_ of the individual. Studying endocrine traits of physique, life reactions, disease tendencies, hereditary history and blood chemistry, one may gain an insight into the composition or constitution of an individual. The endocrine type of an individual is a summary of these, his behaviour in the past, and is also a prediction of his reactions in the future, much as a chemical formula outlines what we believe to be the skeleton of a compound substance as deducible from its properties under varying conditions. Only, admittedly, as yet the endocrine label is but roughly qualitative and most crudely quantitative, whereas the chemical formula is the essence of the exact. However, the fact remains that though we are only upon the first rungs of the ladder, we are upon the ladder. The horizon undoubtedly broadens. We possess a new way of looking upon humanity, a fresh transforming light upon those strange phenomena, ourselves. Of the ugly achievements of that dreadful century, the nineteenth, the most illuminating was the discovery of itself as the _ape-parvenu._ Yes, we are all animals now, it said to itself, and set its teeth in the cut-throat game of survival. But there was no understanding in that evil motto of a disillusioned heart. The ape-parvenu, desperately lonely and secretive, has still to understand himself. Let us be clear if we can. There is perhaps a certain presumption in the phrase, the endocrine type. It is ambitious, and perhaps will not fulfill its promise. But it is useful because it points a parallel and an ideal. As Wilhelm Ostwald never tired of repeating, H_{2}O is a complete shorthand record for the bundle of qualities commonly known as water. It is an example of that highest task of mind, synthesis. It is the highest synthesis of the studies of the internal secretions that certain combinations of them, permutations and blendings of them, are responsible for those unique wonders of the universe, personalities.