To Rokitansky1has been given the credit for teaching that tuberculosis and cancer are incompatible diseases; but since McCaskey,2in 1902, made the statement that he was strongly inclined to doubt that Rokitansky had ever held to this extreme view, it may be well to quote direct from Rokitansky's article on cyst formation: Cyst formation, as a new growth, is rarely found concurrent with tubercle, either in the same organ or in the same organism generally. With regard to tuberculosis and cancer, he said: A similar antagonism, as shown from still more numerous observations, prevails between tubercle and carcinoma. Whenever their general correlation is susceptible of proof, cancer has seemed to succeed to tuberculosis, tubercle rarely to become developed after the extinction of cancer and its crasis. Also: A corresponding result of much interest is afforded by a comparison of the scale of frequency of cancer and tubercle,