Experimental production of squamous-cell carcinomas in the skin of chickens.

Squamous-cell carcinomas, hemangiomas, fibro mas, and papillomas have occurred in the skin of ducks following the local application of a 0.25 per cent acetone solution of methylcholanthrene daily for a period of 1 month (5, 6). The spontaneous disappearance of a high per cent of these neo plasms in the duck has proved to be a feature of considerable interest (7). Attempts have been made infrequently to produce neoplasms in fowls by the local application of carcinogens to the skin. Hartwell (2), in 1951, cited four experiments in which the skin of fowls was treated with 3,4-benzpyrene. In one the skin of pigeons was used, and one spinocellular epithelial neoplasm developed. In three experiments the skin of fifteen chickens was treated, and one bird developed an epithelioma. The spontaneous occurrence of carcinomas in the skin of fowls is apparently infrequent. Olson and Bullis (4) reported one case of a squamouscell carcinoma in the skin of a chicken. Feldman and Olson (1), in 1944, cited only a few previously reported cases in their study of neoplastic diseases in chickens. These authors stated "In the cases