From available publications by deduction the author arrives at the conclusion that cancer is produced by the prolonged contact of living tissue and any substance that is viscous, insoluble in tissue fluids, and toxic. The hyperplasia induced is of a protective nature. These substances imitate in their action the fibrinous exudate that is responsible for the multiplication of cells in repair and after conception, the intermediate mechanism being an affinity of potassium for vitiated cytoplasm and a resulting imbibition of fluid. Because of the ability of potassium in cells to change gamma rays to beta rays, he is led to the view that intensification of gamma rays outside the body will develop increased secondary beta radiation, which will inhibit and destroy the proliferating cells. It now remains to produce evidence that this conception gets somewhere practically.