OBSERVATIONS ON THE ETIOLOGICAL AGENT OF PLASMACYTOSIS OF MINK; EVIDENCE SUGGESTING A RELATIONSHIP OF THE AGENT TO THE GRANULES OF A MYCOBACTERIUM SPECIES.

A hypothesis based on a possible connection between the granules produced by a species of Mycobacterium and the agent causing Plasmacytosis in mink is suggested. The presence of these granules in the identical tissues of mink from which a virus had previously been isolated, is noted. Granules with the ability to produce a "germ tube" with acid-fast staining characteristics were found to be present in these tissues. Preliminary cytological studies have shown these granules to be similar to those described by Much. When tissues containing the granules were injected into guinea pigs, rabbits and chickens and these were later tested with avian tuberculin, positive skin reactions occurred. A disease was reproduced in chickens which simulated avian leucosis. In guinea pigs a disease was reproduced which resembled Plasmacytosis in mink with some histological differences. Rabbits appeared to be refractory to infection with the dosage and route of inoculation used. The results obtained from bacteriological studies, tissue culture, animal inoculation, as well as observations made on the cytological properties of the granules, are described and discussed.