/ ENERGY, The combined action of these { HEALTH, faculties express \ REPRODUCTION. [Illustration: Fig. 79] If this portion of the brain indicates a full development, we say of such a temperament that it is VITAL, because the functions of its nerve-centers are favorable to evolution. As degeneration observes conditions, so endurance and development conform to certain laws, and it is the duty of all truthful inquirers, who believe not only in the progress of human intelligence, but in physical improvement from generation to generation, to ascertain and comply with these essential conditions. When the anterior and middle lobes of the brain are fully developed at their inferior surfaces, it is regarded as an insane temperament, _i.e._ containing the germs of mental and bodily derangement. How shall we distinguish the combination of organic elements, if not by the manner in which they characterize the constitution? Every human being is distinguished by natural peculiarities, both mental and physical. These are indicated not only by the color of the eyes, hair, and skin, and the mental expressions, but in the conformation and capabilities of the corporeal system. The color, form, size, and texture of a leaf indicate to the expert pomologist the nature of the fruit which the tree will bear, but how much more important is it to understand the harmonies of human development. If Prof. Agassiz could determine the form and size of a fish by seeing its scales, and Prof. Owen outline the skeleton of an unknown animal by viewing a portion of its fossil, why should not the physician understand the language of temperaments, since it opens to him the revelations of human development? The sculptor blends character with form, the artist endows the face with natural expression, the anatomist accurately traces the nerves and arteries, the physiognomist reads character, which the novelist delineates and the actor personates, because there are facts behind all these, the materials wherewith to construct a science. In organization there are permanent forces which operate uniformly, thus revealing the order of nature. THE TEMPERAMENTS CLASSIFIED. [Illustration: Fig. 80] We propose to speak of four constitutional variations entitled to separate consideration; the lymphatic, the sanguine, the volitive, and the encephalic. The brain controls all the voluntary, and modifies the involuntary functions of the body. A particular cerebral development modifies the functions of all the bodily organs, and thus tempers the constitution. We shall, therefore, base our classification of temperaments upon the mental and physiological characteristics, which are portrayed by cerebral development. Such an arrangement is illustrated by Fig. 80. THE LYMPHATIC TEMPERAMENT.