Once Golgi invented the staining technique that allowed unprecedented views of the neurons, the Spanish scientist Santiago Ramon y Cajal
went on to do remarkable things with the method. Portraits of the Mind
quotes a piece of Cajal's writing in which he rhapsodizes about the results: "What an unexpected spectacle! On the perfectly translucent yellow background, sparse black filaments appeared that were smooth and thin or thorny and thick, as well as black triangular, stellate, or fusiform bodies! One would have thought that they were designs in Chinese ink on transparent Japanese paper."
Cajal, who is sometimes called the father of modern neuroscience, used Golgi's method to describe the structure of neurons in new detail. Most importantly, he discovered that individual neurons don't connect with each other, paving the way for the realization that they communicate across synapses. This drawing of the eye's retina, dating from 1901, indicates the flow of information through neurons via small arrows.
Image: Courtesy of Juan A. de Carlos / Instituto Cajal