NATURE OF THE FILTRABLE AGENT OF TRACHOMA

Abstract

It is now generally agreed that none of the bacteria which have been found on the trachomatous conjunctiva are concerned etiologically in the disease. In 1912 Nicolle, Blaizot and Cuenod1concluded, on the basis of two filtration experiments in which they had employed modified Berkefeld V filters, that the agent of trachoma was filtrable. In the first experiment a bacteria-free filtrate of trachomatous material produced a disease typical of experimental trachoma in a Macacus inuus (Barbary ape) which was proved to be trachoma by transfer to a blind human eye. In the second experiment a bacteria-free filtrate proved infectious for a chimpanzee. Confirmation of the filtrability of the agent of trachoma has come from the experiments of Thygeson and Proctor2with baboons, Thygeson, Proctor and Richards3with a human volunteer and Julianelle, Morris and Harrison4with Macacus rhesus monkeys. These investi- gators have found