Albert Claude, circa 1950
Courtesy of the Rockefeller Archive Center
For the century following the recognition of the cell as a basic unit of life, biologists, bumping always against the limits of the light microscope, could distinguish within the cellular border only a nucleus and some shadowy forms surrounded by a mysterious jelly. Then, in 1944, Albert Claude in collaboration with Keith R. Porter and Ernest F. Fullam, published the first electron micrograph of a cell. Two years later, Claude published two papers in which he described a method for separating cellular structures intact, making them accessible for a study of their biological activity. The age of modern cell biology had begun.