American physician; born at New York Oct. 28, 1858; educated at the College of the City of New York and at the College of Physicians and Surgeons (M.D. 1881). He took a postgraduate course at the universities of Leipsic, Prague, and Vienna, and on his return to America established himself as a physician in his native city (1883). There he became connected with Bellevue Hospital, the Good Samaritan Dispensary, and other medical institutions. Since 1899 he has been assistant professor of pediatrics at Bellevue Medical College.
Koplik was the first to describe an early diagnostic sign in measles, since known as "Koplik's spots"; and he found, too, the bacillus of whooping-cough. He also introduced the free delivery of Pasteurized milk to the needy poor, in which he was followed later by Nathan Straus.
Besides essays in the medical journals Koplik is the author of "Diseases of Infancy and Childhood," New York, 1902.