Beauty of the Brain
Anatomist Santiago Ramon y Cajal was the first to see--and illustrate--what neurons really do. His exquisitely detailed drawings changed our understanding of the brain and nervous system. Cajal relentlessly pursued his microcopic study of animal tissues, leading to an essential discovery: Brain signals jump from cell to cell rather than flow through a continuous web of fibers, as was believed at the time.
Cajal began to study histology because it was cheap. He was a man of poor health and modest means, and examining stained specimens required little more than a microscope and patience. The fact that he had no access to the fancy tools of leading bacteriologists--he held only an obscure academic post in the scientific backwater of Zaragoza, Spain--turned him toward the study of animal tissues and cells. These "captivating scenes in the life of the infinitely small," as he called them in his autobiography, Recollections of My Life, went on to inspire ideas that overturned how scientists understood the brain and the nerves.
Here are two of his cutaway views of the cerebellum, which coordinates movement. The top drawing has a rich diversity of cells, including treelike Purkinje cells, seen in red and tan, and stellate cells, shown in black. The bottom drawing is a longitudinal cross section of the cerebellum.
Cajal Legacy Instituto Cajal (CSIC), Madrid