Nasopharyngeal washings from a case of epidemic influenza have proven capable of initiating a pathological change in rabbits and in guinea pigs characterized after an incubation period of 1 or 2 days, by some elevation of temperature, reduction in the number of circulating leucocytes, especially of the mononuclears, and by a pulmonary lesion during the period of reaction, which is distinguishable from those accidentally incurred at the time of death.

From one such animal, in the second passage of the virus, an anaerobic coccobacius, corresponding in all respects to Bact. pneumosintes, was isolated by the method employed by Olitsky and Gates.

This organism also proved capable of initiating the pathological change in animals found after inoculation with influenzal material.

The observation of Olitsky and Gates that the presence of this organism in the lungs of experimental animals predisposes to pulmonary localization of other bacteria with the production of definite pneumonic lesions has been confirmed.

Bact. pneumosintes infections may be induced by subcutaneous injection of infected material.