In 1912 Casimir Funk coined the term vitamin to label a vital factor in the diet: from the words "vital" and "amine," because these unknown substances preventing scurvy, beriberi, and pellagra, were thought then to derive from ammonia. In 1913 Elmer McCollum discovered the first vitamins, fat-soluble vitamin A and water-soluble vitamin B (in 1915; later identified as a complex of several water-soluble vitamins) and named vitamin C as the then-unknown substance preventing scurvy. Lafayette Mendel (1872-1935) and Thomas Osborne (1859–1929) also performed pioneering work on vitamins A and B.