The author,1 an anatomist, notes that the development of the human both in and outside of the uterus is characterized by a considerable degree of retardation as compared to other mammals. This retardation, in his opinion, is the cause of a process of somatic immaturity that he calls 'foetalization', of which he describes several instances in human morphology. These views would explain the degree of dependency of the child on the mother, characteristic of the human species; also, they would explain the morphologic and physiologic differences