Primary carcinoma of the lung has attained a position of major interest in malignant neoplastic disease, through at least a more common recognition, if not more frequent occurrence, within recent years. Likewise asbestosis has assumed a rank of considerable importance in industrial medicine. Workers in the mines of the Erz Mountains, on both the Bohemian and the Saxon sides, have suffered heavily for some centuries from pulmonary disease now recognized as carcinoma and well known as Schneeberg and Jáchymov (Joachimstal) lung cancer. Pirchan and Šikl (1), in a report upon a series of these cases, state that “there were only moderate degrees of anthracosis,” and they are not inclined to attach any particular importance to the degree of pneumonoconiosis as a cause of the cancer, but consider that “the question may be somewhat different with regard to the quality of the foreign substance deposited in the lung.” Chemical analysis in one of their cases revealed “only calcium, magnesium, aluminum, silicic acid, chlorides, and phosphates; no trace of arsenic, bismuth, cobalt, nickel, or uranium was found.” They lay suspicion, as others have done, upon radium emanation and upon arsenic, both factors being encountered in the Schneeberg and Jáchymov mines. Rostoski, Saupe and Schmorl (2) found severe “anthracosis” in Schneeberg miners the subjects of lung cancer and are inclined to attribute the causation of the cancer to the anthracosis, while Simpson (3) states that pulmonary cancer is a rare complication of silicosis in South African miners. Schulte (4) has reported lung cancer in pneumonoconiosis among coal miners, and Saupe (5) has recorded two cases in arsenic miners. There appears to be no previous report of its occurrence in asbestos miners or mill workers, although the record of autopsy examinations of cases of asbestosis is not large.