Dr. Albert Claude, 84, a Belgian cytologist who was a co-winner of the 1974 Nobel Prize for medicine for his cancer research and who was a pioneer in the use of electron microscopy and centrifugation in the study of cells, died Sunday night at his home in Brussels. The cause of death was not reported.

Dr. Claude shared the Nobel award with fellow Belgian Christian de Duve and American George Palade. The Swedish institute cited their research as "largely responsible for the creation of modern cell biology through their discoveries concerning the structural and functional organization of the cell."

A spokesman for the institute said their work showed how cells secrete substances essential to life, and how specialized cell units dispose of worn-out parts and defend against foreign organisms such as bacteria.

At the time of the award, de Duve said the results of their research might provide "new openings in studies of aging, arteriosclerosis, the immune syndrome, and the chemical treatment of cancer."

Work performed by Dr. Claude contributed to cancer research by showing how substances harmless in themselves could become toxic within the cell and cause cancer. Such particles can now be isolated and analyzed to see if they cause cancer. His research also contributed to studies on arteriosclerosis, indicating a connection between that disease and a deficiency in the lysosome enzymes.

Dr. Claude did much of his most important work during an 18-year period beginning in 1929, when he was affiliated with the Rockefeller Institute in New York, mainly in its Department of Pathology and Bacteriology. During his years there, he made the first successful application of the electron microscope to the study of cells. He had isolated the first cancer virus in 1933, and 11 years later made the first picture of the virus with an electron microscope.

He also developed centrifugation for cell study, and through these and other techniques created the tools he needed to inventory the chemical composition of cells. A centrifugal process that he developed enabled physicians to locate tumors in the body more quickly.

Dr. Claude was born in Luxembourg and reared in Belgium. He had dropped out of high school and was an apprentice draftsman in a steel mill when World War I broke out. During the war, he worked for British intelligence and earned citations from the British and the Belgian defense ministry. Despite his lack of formal education, the Belgian government granted him a special allowance to enter medical school after the war.

He received his medical degree from Liege State University in 1928, and further scholarships enabled him to work in Germany at the Kaiser Wilhelm Institute in Dahlem and the Institute for Cancer Research in Berlin.

After leaving the Rockefeller Institute, he returned to Belgium. In 1950, he became head of the institute for cytology and experimental cancerology of Brussels University. He later was a professor at Brussels and Liege universities and head of the Brussels Jules Bordet cancer institute.

In addition to the Nobel Prize, his awards included the U.S. National Science Foundation prize in 1966, the Gross-Horwitz prize of Columbia University in 1970 and the Paul Ehrlich prize of Frankfurt University in 1971.

His marriage to the former Joy Gilder ended in divorce. They had a daughter, Dr. Philippa Claude, a cell biologist.