Inspired by what he saw, Cajal worked “with a fury,” typically spending 15 hours a day staring into the microscope and recording his observations. Over the course of five decades, he amassed nearly 3,000 drawings. He drew freehand in pencil, later going over the sketches in India ink and washes. He seldom made mistakes; in the drawings at the Grey, whited-out lines and corrections are rare.
Even more than the magical Golgi stain, it was Cajal’s trained eye that made this groundbreaking achievement possible. “Golgi and many other scientists in Europe were looking at the same tissue, with the same stain, in the same way, but only Cajal was able to see structure inside of that stained tissue,” said Carl Schoonover, a neuroscientist at Columbia University. “He was able to see and analyze these extremely difficult-to-see shapes, then communicate his findings through these beautiful drawings.”
For the discovery of the neuron, the basic building block of the brain, Cajal would eventually share the Nobel Prize in Medicine with Golgi in 1906. “Like Einstein in physics, Cajal defined the parameters of modern neuroscience,” Schoonover said. “The specific cellular features of the neurons and how they’re arranged, which he drew so beautifully, is monumental.”