The Pathology of Malignant Epithelial Growths of the Skin

believes from bis numerous investigations that no one agent is concerned in the malignant proliferation of epithelial tumors, ami that a multiple etiology is responsible for the cutaneous carcinomata.A strong arguinent against the theory of the parasitic-nature of the disease is the development of epit ichomata following exposure to sunlight, Hiintgeu rays, and other radiant energy.The action of such chemical sub¬ stances as arsenic, tar, tobacco, and scnrict-rcd on epithelium, for wiuch they have a special predilection, goes to show that a variety of agents have the power to stimulate epithelial mitosis which may pass into malignancy.Carcinomata which develop on scar tissue or ante¬ cedent conditions of the skin like lupus, syphilis, etc., suggest the I( ea °' ""splaccd cells in some cases and in others with degenerative processes which interfere with the functional life of the cells, followed as a consequence by overgrowth of the cells.