The 51-year-old manager of the clinical chemistry division at Georgetown University Hospital was found stabbed to death early yesterday by coworkers who discovered his body in a little-used stairwell near the laboratory where he worked.

The victim, Lancaster B. Knott Jr. of Manassas, had worked at the hospital for 26 years. Police investigators questioned Knott's fellow employes in an effort to determine a motive.

Coworkers began searching for Knott after he failed to show up for his early-morning shift at the laboratory, which conducts medical tests for patients at the hospital. The body, discovered shortly after 5 a.m., bore multiple stab wounds, according to police. The stairway where he was found leads to the laboratory from an outside entrance.

Knott's wife, Janet, said that her husband usually left for work between 3:30 a.m. and 4 a.m. to avoid rush-hour traffic into Washington. She said her husband liked to arrive at work during the morning shift change so that he could review the work done overnight in the laboratory.

"He was a very quiet man who liked to do his job and mind his own business," Mrs. Knott said in a telephone interview yesterday. "I can't believe it . . . . Somehow there's no sense to it." The Knotts, who have four children, recently celebrated their 25th wedding anniversary.

Mrs. Knott said she learned of her husband's death from her parish priest and her husband's supervisor at the hospital, who located her at a Manassas bowling alley where she was participating in her regular Tuesday morning women's league.

The priest, the Rev. Gerald Goggin, said that he was informed of the slaying at 7:30 a.m. by Knott's supervisor, Dr. Charles Rath.

Goggin said in an interview that Knott was a "faithful attendant" at church services at All Saints Parish in Manassas and was an usher at the 9 a.m. mass each Sunday. Goggin described Knott as a "very generous and open person." Knott also was a member of the Knights of Columbus, Goggin said.

Knott, who was born in Washington, was a graduate of St. John's University in Annapolis, where he studied chemistry, and had taken additional courses at George Washington University. Knott started working at the hospital as a technician, was promoted to chief technician and about two years ago was named manager of the laboratory, his wife said. She said he enjoyed fishing and gardening in his spare time.

"I keep thinking maybe someone will call me and tell me it's a dream," Mrs. Knott said.

"It's just a senseless thing," said Knott's 16-year-old son, William Patrick, who joined in the telephone conversation.