Seeing the inner workings of a hand, or the nervous system surrounding the spleen, doesn’t seem appealing to most people. However, “Gray’s Anatomy,” the corpus of medical students and artists ...

The neuron theory There was, however, a tissue that seemed to belie cell theory — nervous tissue. Because of its softness and fragility, it was difficult to handle and susceptible to deterioration.

When it came to late-19th century brain studies, things were complicated further by the nature of nervous tissue. Neurons were hard to see without special staining.

Colorful transparent slides, mounted with slivers of nervous tissue from sacrificed animals still gummy to the touch from chemical treatments, lay scattered on the worktable.