Ferris Jabr has begun a series called "Know your neurons", which will be a tour of the types of neurons. The first installment ("Know Your Neurons: The Discovery and Naming of the Neuron") covers the science that established the existence of neurons, in the late nineteenth century, when Santiago Ramón y Cajal used the staining technique developed by Camillo Golgi to visualize and draw detailed pictures of the microscopic cells. At issue was whether all the nerve fibers ultimately merged into a connected network, or reticulum:
Golgi’s “black reaction,” combined with the painstaking work of Karl Deiters and others, clearly distinguished two kinds of projections from cell bodies in nervous tissue: a long slender cable that did not seem to branch much and a cluster of shorter branching fibers. Even though Golgi saw that one cell body’s branching fibers did not fuse with another’s, he did not reject Gerlach’s idea of the reticulum—instead, he decided that the long slender cables probably connected to form one continuous network.
Ramón y Cajal showed that the fibers did not merge into a continuous reticulum, the essential data supporting the neuron theory. I'll look forward to more in the series.
