More than three decades after the German biologists Theodore Schwann and Matthias Schleiden first proposed that the cell was the basic functional unit of all living things, in 1838, many of the world’s leading histologists still disagreed about the fine structure of the nervous system. Some maintained that the brain was also made of cells, while others argued that it consisted of a continuous network of tissue, or “reticulum,” formed by the fused processes of nerve cells.
In 1873, the Italian physician Camillo Golgi described a staining technique that helped resolve the issue. Golgi set up a makeshift laboratory in the kitchen of the small-town hospital near Milan where he worked, and spent his evenings preparing brain slices for imaging. Under the glow of candlelight, he discovered that by first hardening a sample of nervous tissue in potassium bichromate and ammonia, then immersing it in a silver nitrate solution, he ...
