It is one of Cajal’s legacies that he never performed a single experiment in cell biology—or at least an experiment in the traditional sense. To see his drawings of neurons is to realize how much can be learned by just seeing. It is to return to characters such as Da Vinci or Vesalius who imagined drawing as thinking: an astute observer and draftsman could generate a scientific theory as much as an experimental interventionist. Cajal sketched what he saw, and his understanding of how the nervous system “worked” emanated entirely from drawing cells and drawing conclusions.
