The experimental chronic granular conjunctivitis first induced in Macacus rhesus with pure cultures of Bacterium granulosis, has been transferred by direct tissue passage to the chimpanzee, baboon, and to other Macacus rhesus through at least 4 successive passages.
This experimental chronic granular conjunctivitis preserved the clinical and histological characters throughout the several passages, and the lesions have been shown to be infective as early as 17 and as late as 204 days after the original culture inoculation.
Bacterium granulosis can be recovered from the inoculated animals and has been found in microscopic specimens of human and monkey tissues. The great difficulty of its recovery in culture and its demonstration in sections of tissues and in films is not necessarily an indication of its absence from the lesions. The methods employed to recover or to find the organism may not be the most favorable to be discovered.
No other microorganism obtained from the human cases of trachoma produces in animals effects comparable to those induced by Bacterium granulosis. In the absence, therefore, of indications to the contrary, we may consider that in Bacterium granulosis we have the inciting microorganism of trachoma in man and its equivalent, granular conjunctivitis in monkeys.