A short time ago trachoma in this country was regarded as an exotic disease. Guardianship, to prevent its introduction by immigrants, is still necessary; but we have learned now, largely through investigations of the Public Health Service, that trachoma is prevalent in many sections of the United States. Each year it becomes a more important and difficult public health problem. Our lack of knowledge of its real nature renders uncertain our efforts to establish a rational and intelligent prophylaxis.
In studying the etiology of trachoma, the diagnostic confusion which exists concerning it has caused some earnest students to deny that the disease is a morbid entity, and to assert that it is simply the reaction of the conjunctiva, under certain circumstances, to some of the well-known bacterial infections, such as the gonococcus or Koch-Weeks bacillus.1 Axenfeld2 recently has probably expressed the generally accepted opinion. He affirms the "etiologic