[Boeck's sarcoid].

The various theories regarding the etiology only serve to demonstrate how much there is yet to be proved about this disease. Boeck originally considered the disease to be a constitutional one, caused by a non-virulent form of tubercle bacillus. This opinion is still held by a large number of men. A comparatively high proportion of cases will later develop an active tuberculosis. Pinner believes that tuberculous lesions develop as a part of the sarcoid lesions and not as a separate disease concurrent with the sarcoidosis. Kyrle, Wende, and Goeckerman, have demonstrated tubercle bacilli in early cases, and believe that if early lesions were examined more frequently the percentage in which tubercle bacilli are found would increase. Others feel that it may be a nonspecific tissue response to various types of organisms, and perhaps to several organisms at the same time. In this connection, tubercle bacillus, leprosy bacillus, spirochaeta pallida, and Leishmania have been mentioned. Pullinger, Ross, and others have advanced a hypothesis that it may be a disease of the reticulo-endothelial system, comparable to Hodgkin's disease. Kissmeyer and Nielsen believe that it is a chronic infectious granuloma. They advanced the theory that it may be due to a virus infection and that it is a specific pathologic entity.