This work deals with a multitude of subjects which should be of vital interest to a variety of people, the physician, the employer, the worker, and last but by no means least, the legislator. For the physician, especially, it contains information concerning the diseases which are caused or aggravated by the different kinds of employment. Although the various articles are from the pens of different writers, they show a commendable tendency to stick closely to known facts. The chapter on "Cancer and Occupation" is an example of this. The more important theories of the etiology of cancer are discussed in an unbiased manner.
The conclusions reached may be briefly summarized as follows: Concerning a specific infection, "Repeated attempts to isolate such an agent from mammalian tumors have invariably failed"; the question of contagion "has never been demonstrated"; concerning heredity "while the data collected up to the present time from animal