THE PROBLEM OF THE ETIOLOGY OF TRACHOMA: RICKETTSIA

It is now generally accepted that Bacterium granulosis (Noguchi) does not cause trachoma.¹ Its pathogenic action consists in the production of folliculosis.²

The long-discussed epithelial cell inclusions of Prowazek and Halberstädter were discredited for a considerable length of time by the finding of different nonspecific inclusions of extracellular and intracellular origin on the trachomatous conjunctiva and of similar inclusions on conjunctivas affected with several other forms of conjunctivitis. Recent investigations of Lindner,³ Aust,⁴ Taborisky⁵ and Rötth,⁶ but especially those of Thygeson,⁷ Thygeson and Proctor,⁸ Thygeson, Proctor and Richards⁹ and Thygeson and Richards,¹⁰ have helped to disclose the role of the inclusions. In a report¹¹ read before the Fifteenth International Ophthalmologic Congress in Cairo, Egypt, in 1937 I showed that the etiologic role of the constituents of the inclusion body, the initial and the elementary body had not been