Watson graduated in 1934 with a bachelor's degree from the University of Toronto and in 1937 with an M.Sc. from Dalhousie University. During his years as a graduate student at Dalhousie, he was also employed as an assistant by the Biological Board of Canada. From 1937 to 1938 he worked for the Fisheries Research Board of Canada,[2] where he studied the bacteriology of fish spoilage.[3][4] In 1938 he went to the United States.[5] In 1941 he graduated from the University of Wisconsin with a Ph.D. in bacteriology.[2] His Ph.D. thesis is entitled The biological and physical properties of tuberculin constituents.[6] At the University of Wisconsin, Watson was from 1941 to 1942 a research fellow and a research associate in agricultural biology. In 1942 he was a visiting assistant at the Rockefeller Institute for Medical Research. From 1942 to 1944 he worked in Toronto at the Connaught Laboratories.[2] From 1944 to 1946, he worked on the development of a typhus vaccine for the U.S. Army in the United States biological weapons program.[7][2]
In 1946 Watson became a naturalized U.S. citizen. From 1946 to 1949 he was an assistant professor in agricultural biology at the University of Wisconsin.[2] In the department of microbiology of the University of Minnesota Medical School, he became in 1949 an associate professor and then became a full professor, retiring in 1984 as professor emeritus. From 1964 to 1984 he was the head of the department. He served as director of the Minneapolis War Memorial Blood Bank.[7]
At the University of Minnesota, Watson did research on several diseases, but his discoveries about endotoxin shock might be his most important and fundamental work.[7] He also did research on host-parasite relationships.[2]
Watson was elected in 1953 a fellow of the American Association for the Advancement of Science.[8] Upon his retirement in 1984, some of his former students established the Dennis W. Watson Fellowship for University of Minnesota graduate students in microbiology and immunology.[9]
He married in 1941.[2] His wife died in 2001. They had a daughter, Catherine, and a son, William. Upon his death in 2008 at the age of 94, Dennis W. Watson was survived by his two children, five grandchildren, and three great-grandchildren.[7] His son William (who died in 2020) was for many years a professor of world history in the department of social sciences of Colorado Christian University.[10]
Cromartie, William J.; Bloom, Walter L.; Watson, Dennis W. (1947). "Studies on Infection with Bacillus anthracis: I. A Histopathological Study of Skin Lesions Produced by B. anthracis in Susceptible and Resistant Animal Species". The Journal of Infectious Diseases. 80 (1): 1–13. doi:10.1093/infdis/80.1.1. JSTOR30089238. PMID20341537.
Cromartie, William J.; Watson, Dennis W.; Bloom, Walter L.; Heckly, Robert J. (1947). "Studies on Infection with Bacillus anthracis: II. The Immunological and Tissue Damaging Properties of Extracts Prepared from Lesions of B. anthracis Infection". The Journal of Infectious Diseases. 80 (1): 14–27. doi:10.1093/infdis/80.1.14. JSTOR30089239. PMID20283795.
Watson, Dennis W.; Cromartie, William J.; Bloom, Walter L.; Kegeles, Gerson; Heckly, Robert J. (1947). "Studies on Infection with Bacillus anthracis: III. Chemical and Immunological Properties of the Protective Antigen in Crude Extracts of Skin Lesions of B. anthracis". The Journal of Infectious Diseases. 80 (1): 28–40. doi:10.1093/infdis/80.1.28. JSTOR30089240. PMID20283797.
^Watson, Dennis W. (1939). "Studies of Fish Spoilage: IV. The Bacterial Reduction of Trimethylamine Oxide". Journal of the Fisheries Research Board of Canada. 4b (4): 252–266. doi:10.1139/f38-023.
^Watson, Dennis W. (1939). "Studies of Fish Spoilage: V. The Role of Trimethylamine Oxide in the Respiration of Achromobacter". Journal of the Fisheries Research Board of Canada. 4b (4): 267–280. doi:10.1139/f38-024.