Abstract
Primary carcinoma of the lung has been designated as a new disease. It is certain that no longer than twenty years ago it was rarely recognized during life and only infrequently at autopsy. The statistics gathered and summarized by Fried in his recent book1 show that a steady increase can be noted in the ratio which this form bears to all other carcinomas. There are probably two points which, considered in this connection, would seem to explain the increase in frequency. In the first place, many more people are living to reach the so-called "cancer age," that is, middle life. Among these people, this form of carcinoma manifests itself and is recognized more often. Here, then, is a real increase in frequency which is probably running parallel to the increase in carcinoma in general. In the second place, means of diagnosis have been greatly improved in the