Some aspects of adult human anatomy are beautifully organized to provide maximal functional efficiency or strength, but it can be difficult for new students to appreciate this organization because adult structures are often highly modified from their original embryonic state. The founder of the discipline of neurology, Ramon y Cajal (1852–1934), was stymied in his attempts to understand the cellular organization of the central nervous system (CNS), and proposed that, “Since the full grown forest turns out to be impenetrable and indefinable, why not revert to the study of the young wood, in the nursery stage....” By looking at embryos, he discovered that the nervous system was composed of individual cells (neurons) and was the first to elucidate the organization of the forebrain and cerebellum.