Belgian biologist Albert Claude, working at The Rockefeller Institute for Medical Research (now The Rockefeller University) in the 1930s, was attempting to isolate a cancer-causing agent from chicken tumors when he noticed that the supernatants of lysed cells contained a strange aggregate, which appeared to be composed of large numbers of small particles with unusually high amounts of RNA. Claude named the mysterious particles “microsomes” and hypothesized in a 1943 Science paper that they “may be endowed with the property of self-duplication.” But because microsomes were too small and highly refractive to be observed using traditional light microscopy and staining techniques, Claude was unable to study them in further detail.
Luckily, Claude's Science publication came to the attention of microscopy specialist Ernest Fullam, who operated one of the few electron microscopes in the country for a chemical company in New York City. Fullam's superiors were eager to test out the ...
