Santiago Ramón y Cajal

Santiago Ramón y Cajal, who was born in 1852 in a small village in the north of Spain, wanted nothing more as a boy than to be a painter. His father, a country doctor who would later become a professor of anatomy, considered art a waste of time and was determined to turn his son into a man of science. Santiago, for his part, seemed determined to resist. He drew on every surface he could find, quarrelled with his teachers, and at the age of eleven was briefly locked up by the local authorities after building a small homemade cannon and firing it at a neighbour's gate.

Exasperated, his father tried discipline of a more practical kind, apprenticing him first to a barber and then to a shoemaker. What finally changed the boy's direction, however, was not punishment but drawing. His father began taking him to old graveyards to collect human bones, which Santiago was asked to sketch for anatomy lessons. To his own surprise, he found the bones beautiful, and the habit of looking closely, which had always made him a difficult pupil, began to make him an excellent student. He went on to study medicine and qualified as a doctor in 1873.

The question that would occupy him for the rest of his life was one that nobody had been able to answer: what is the brain actually made of? Under the microscopes of the time, nervous tissue looked like a hopeless tangle. The most influential theory, defended by the Italian scientist Camillo Golgi, held that the nervous system was a single continuous network, a kind of web in which every fibre was joined to every other. Ironically, the best tool for studying the brain had also been invented by Golgi himself. It was a staining method, known as the "black reaction," which coloured only a few nerve cells, apparently at random, but coloured each of them completely, so that it stood out in black against a pale background.

Cajal first saw slides prepared with Golgi's method in Madrid in 1887, and he understood immediately that he was looking at something extraordinary. He refined the technique, applying it to the brains of birds and young animals, whose tissue was easier to stain, and spent long nights at the microscope drawing exactly what he saw, cell by cell, in ink. He later called 1888 his greatest year. What his drawings showed, again and again, was that the nerve cells were not fused into a single web at all. Each one was a separate unit, which came very close to its neighbours and passed signals to them, but never actually joined them. This idea, which became known as the neuron doctrine, is the foundation of modern neuroscience, and many of his drawings are still reproduced in textbooks today.

In 1906, the Nobel Prize in Physiology or Medicine was awarded jointly to Cajal and Golgi for their work on the structure of the nervous system. The two men met in Stockholm to receive it, and the ceremony was not quite the celebration it was meant to be. In his Nobel lecture, Golgi defended his network theory and attacked the neuron doctrine, while Cajal, using pictures made with Golgi's own stain, explained why the network did not exist. The boy who had been forced to give up painting had become a scientist, and he had won science's highest prize by refusing to stop drawing.