Basil Constantine Hatziolos, 100, a professor emeritus of animal pathology who did research at the University of Maryland into immunology, metabolic disorders, viral diseases and bovine cancer, died Nov. 19 at his home in Washington.

According to a funeral home spokesman, Dr. Hatziolos's death was attributed to senescence, or aging.

Dr. Hatziolos wrote books and nearly 100 scientific papers. He was honored in his native Greece for his book on the problems of livestock breeding in that country.

He had lived in Washington since the mid-1940s, when he was sent to this country to procure animals to restore Greece's war-depleted livestock. He was on the faculty of the University of Maryland from 1947 to 1972.

Dr. Hatziolos received degrees from French veterinary schools, a doctorate in animal husbandry from the University of Paris and another in animal pathology from the University of Berlin.

In Greece, he was chief veterinarian in the horse production branch of the agriculture ministry. During World War II, he served with the Greek Army on the Albanian front.

Dr. Hatziolos was a member of such professional organizations as Sigma Xi, the American Veterinary Medical Association, the American Academy of Science, the American Association of University Professors and the Prometheus Society.

Survivors include his wife of 55 years, Anne Hatziolos of Washington; two daughters, Elizabeth Demetra Harris of Baltimore and Chevy Chase and Marea Hatziolos Grant of Chevy Chase; a brother; and two grandsons.