Golgi, Cajal and the neuron

Before the 1870s the stains used on brain tissue colored almost everything at once and hid its finer structure. Camillo Golgi, born near Brescia in 1843 and trained at Pavia, became chief medical officer of a hospital for the chronically sick at Abbiategrasso in 1872 and worked on the nervous system in a small kitchen he had turned into a laboratory. In August 1873 he published a method in which tissue hardened in potassium or ammonium dichromate was soaked in silver nitrate. Only a few nerve cells turned black, but each was stained whole, cell body, dendrites and axon. He called it the black reaction.

Golgi read his preparations as showing that nerve fibers joined in a diffuse network, and for years his method was little used. Santiago Ramón y Cajal, born in 1852 in Petilla de Aragón and a former army doctor in Cuba, was professor of anatomy at Valencia when he first saw Golgi preparations in 1887, at the Madrid home of Luis Simarro. He refined the stain, applied it to the brains of young animals, and in 1888 published a study of the bird cerebellum.

Cajal concluded that the brain and spinal cord are made of countless separate units, each with its own processes, which end freely and pass signals to other cells by contact across the spaces between them. He recorded what he saw in thousands of drawings. In 1891 Wilhelm von Waldeyer-Hartz drew on this work in a review that introduced the word neuron, and the view became known as the neuron doctrine.

The Nobel Prize in Physiology or Medicine for 1906 went jointly to Golgi and Cajal "in recognition of their work on the structure of the nervous system." They were the first scientists to share a medicine prize. Golgi still held that the nervous system was a continuous network and defended that view in his Nobel lecture.

Cajal held chairs at Valencia, Barcelona and, from 1892, Madrid. Golgi spent his career at Pavia, where he took the chair of general pathology in 1881 and was for many years rector of the university.