PARIS

Photosensitization  Photosensitization was a subject on the program of the Société de pathologie comparée, at its recent annual session. Professor Jausion treated photosensitization with reference to man, M. Richert with regard to animals, and M. Dufrénoy in connection with plants. Dr. Guillaume considered, in a comprehensive paper, the physical bases of the phenomenon. Professor Jausion's conclusions give a summary of the present state of our knowledge with reference to photosensitization in man. As he views it, photosensitization is a phenomenon common to all beings and substances. It is evident in many minerals and it is a question whether the photosensitization of living organisms is not simply the photosensitization of the mineral elements that they contain. We may assume that there is a fluorescent substance the variable amount or activity of which (and likewise the variable amount or activity of the solar or therapeutic radiations emitted from the exterior) would explain