Evidence accumulated in many clinics by different observers has established beyond peradventure the existence of sickle cell anemia as a distinct clinical entity. Although the condition was first recognized by Herrick and reported as early as 1910,1 the relatively high morbidity among negroes was not suspected prior to the reports of Huck2 and Sydenstricker3 in 1923. The latter found sickle cells in the blood of 0.6 per cent of a large number of negroes examined. More recently Cooley and Lee4 examined all negroes admitted to their clinic during a period of ten months, 400 patients, and found sickle cells in 30 of them, that is, in 7.5 per cent. Such an unexpectedly high incidence should challenge one to a clearer knowledge and more ready recognition of this condition.
Sickle cells are red blood corpuscles which have assumed unusual shapes through some influence, probably a perversion of