As a young research microbiologist, Dennis Watson, who later became a University of Minnesota professor, made inroads in the fight against diseases such as typhoid and tuberculosis.

Watson, a native of Canada who worked for the U.S. Army's chemical warfare department during World War II, died Dec. 1 in St. Paul after a stroke. The St. Paul resident was 94.

A native of Morpeth, Ontario, he received his Ph.D. in microbiology in 1941 from the University of Wisconsin, where he later worked.

Early on he studied the microbiology of fish. He also assisted in the development of a typhus vaccine used to protect Allied soldiers during World War II.

During the war, he worked for the U.S. Army's effort in defense against biological warfare, such as anthrax.

He joined the University of Minnesota in 1949, becoming the head of the microbiology department in the university's school of medicine. He led the department from 1964 to 1984.

At the university, "he made strides particularly in medical microbiology in the fight against infectious diseases," said Dr. Ashley Haase, who succeeded Watson as head of the department.

According to his department biography, he made important contributions to the understanding of host-parasite relationships.

"He was a great educator, teacher and mentor to a generation of graduate students and postdoctoral fellows," said Haase.

Among several diseases and illnesses on which he worked at the University of Minnesota was endotoxin shock.

His discoveries about the biology of the illness were once thought to be "highly radical and not believed," said Pat Schlievert, a University of Minnesota professor of microbiology. Watson's work is still at the foundation of research of this illness, which kills nearly 100,000 people in the United States every year.

"Dennis was the scientists' scientist," said Schlievert, a former postdoctoral associate of Watson's. "[He taught me] to be sure my graduate students and postdoctoral associates were given enough free rein and a large enough project to allow them to develop as independent thinkers and researchers."

Watson led many professional groups, including the American Society for Microbiology, where he was president in 1968-69.

He was a regent's professor, and played leadership roles in several organizations, including the National Institutes of Health and the Minnesota State Board of Health. He also was director of the Minneapolis War Memorial Blood Bank.

After retiring in 1984, he spent more time on his hobbies, sailing and photography.

His wife, Alicemay, died in 2001. He is survived by a daughter, Catherine Robinson of Roseville; a son, William of Cuchara, Colo.; five grandchildren and three great-grandchildren.

A private family service will be held.