Leukemia, 1899.

Leukemia, a malignant cancer of the blood, was first described in 1845 by Dr. Rudolf Virchow, a German politician whose wide-ranging interests led him to significant discoveries in cell biology, pathology and anthropology. Although Dr. Virchow's name appeared often in The New York Times, mostly in the late 19th century, his discovery of leukemia was not mentioned until Feb. 22, 1970, in an article by Dr. Lawrence K. Altman. Of course, that was not the first time the disease was mentioned in the paper. That happened on Dec. 6, 1899, when Maj. Samuel T. Armstrong, surgeon of the 32nd Infantry, died in Manila. ''The cause of death,'' the brief obituary said, ''is given as leukemia.'' [ABSTRACT FROM AUTHOR]