The Solar Keratoses and Cutaneous Cancer

The face, neck and hands comprise but a small portion of the surface of the human body, yet, according to my personal observations, 49.6 per cent. of all cancers are cutaneous cancers of these parts. It may be admitted that cancer beginning at the mucocutaneous margin of the lip is due to a special class of causes — smoking, traumatism during shaving, eating, etc.; but if cancer of the lip be eliminated and considered as a special form of the disease, there still remains 37.7 per cent, situated on those regions exposed to solar light. Unna wrote of sailors' cancer, which manifestly occurs in men exposed to much direct and reflected insolation. Hyde asserted that light is productive of cancer of the face and included cancer of the mucocutaneous margin of the lips in the general classification. I believe with Dubreuilh that they should be classified and studied aside from