The increasing use of roentgen rays in the treatment of cutaneous diseases make the fundamental laws of their production and their physical characteristics of more than passing interest. That the busy practitioner cannot spend the time to become a trained physicist is obvious, but it is equally certain that some general ideas may be of value in the selection of apparatus and in the rational use of the roentgen ray. While a single, brief article cannot fully serve this purpose, it may be of service in presenting the main physical features.
ORIGIN OF ROENTGEN RAYS
Roentgen rays are one manifestation of what the physicist refers to as energy of radiation, of which light and radiant heat are the more generally known. These radiations are originated by some disturbance of the minute parts of which matter is composed, i. e., of molecules, atoms or of subatomic bodies called electrons. The latter