environment--is to some extent growth in degeneration and senility. It is not carried to so low a degree as in the apes, although by it man is to some extent brought nearer to the apes, and among the higher human races the progress towards senility is less marked than among the lower human races. The child of many African races is scarcely, if at all, less intelligent than the European child, but while the African as he grows up becomes stupid and obtuse, and his whole social life falls into a state of hide-bound routine, the European retains much of his childlike vivacity. And if we turn to what we are accustomed to regard as the highest human types, as represented in men of genius, we shall find a striking approximation to the child type." The face, in its contest for existence with the brain, has finally caused both the cranium and the jaws to assume (for defence and food purposes) a lower type, although as regards existing functions and the higher standpoint of environment the infantile type must be considered the higher. Still a casual glance at the Ascidian tadpole shows that deficient as is the development of the ganglia afterward forming the medulla, the face is still more deficient. The face, as Minot shows,[64] is a characteristic of the higher vertebrates, and acquires increased importance with rise in the evolution. The position of the face in embryonic development is originally determined by the head-bend. If a median, longitudinal section of the head be imagined to occupy a rectangular area divided into quarters, then the lower posterior quarter corresponds to the mouth region, the other three-quarters to the brain. As development progresses, the mouth quarter so disproportionately enlarges in relation to the rest of the head as to project forward in front of the fore-brain. In this stage, which is represented by the adult amphibians, the bulk of the facial apparatus is very great, proportionately to the cranium. In the reptiles the mouth region is elongated still further in front of the brain-case, resulting in the long snout. In mammals a third stage is established by the great increase in size of the brain, especially of the cerebral hemispheres. In consequence the brain comes to extend over the snout, as it were; in man, whose brain has the maximum enlargement, the facial apparatus is almost entirely covered by the brain. In the course of evolution the face, while serviceable to the animal for certain reasons of general constitutional character (food-getting, means of defence and means of obtaining mates), is less so than brain growth. A struggle for existence, therefore, inevitably results between the tendency of the face to appropriate power of growth and the like tendency of the brain, which, in defective organisms, produces marked reversions of the one for the benefit of the other. This struggle is further complicated by the embryonic relations to both of the hypophysis, since this body