In 1933, Wendell Stanley purified a sample of tobacco mosaic virus (TMV) and finds crystals. This suggested, contrary to contemporary scientific opinion, that viruses were not just extremely small bacteria, for bacteria do not crystallize.

In 1946, The Nobel Prize in Chemistry 1946 was divided, one half awarded to James Batcheller Sumner “for his discovery that enzymes can be crystallized”, the other half jointly to John Howard Northrop and Wendell Meredith Stanley “for their preparation of enzymes and virus proteins in a pure form.”