Widal reaction

Wi·dal \vē-däl\ Georges–Fernand–Isidore (1862–1929), French physician and bacteriologist. Widal held a professorship of pathology and internal medicine at the University of Paris. In 1896 he developed the Widal reaction, a procedure for diagnosing typhoid fever based on the fact that antibodies in the blood of an infected individual cause the bacteria to bind together into clumps. In 1906 he recognized that the retention of sodium chloride was a feature found in cases of nephritis and cardiac edema, and he recommended salt deprivation as part of the treatment for both diseases.