Solution of the problems of the physical basis of personality would seem so urgent a need that not a few have found satisfaction in systems such as palmistry and phrenology; in these pages the author has exploited endocrinology in an energetic and perhaps not altogether unsuccessful attempt to force it into a similarly facile system. Man dominated by his ante-pituitary has, it appears, a superb brain, whereas his post-pituitary energises the tender emotions and if excessive induces anxiety neuroses. Courage and other qualities attributed to animals are apportioned to suprarenal activity; vitality and sensitivity are controlled by thyroid secretion, a fluctuation of which may bring about manic-depressive insanity. The thymus preserves childlike characters