Summary of the Results of Experi- Ments on the Pathogenesis O F Epithelial Growths I. the Experimental Prodijction of Mammary Carcinoma on Rabbits

In the course of the past five years in experiments on 188 animals, we have succeeded in producing twenty-three cases of cancroid and adeno-cancroid resembling that observed in man. These epithelioniata were produced by injection of liquid tar extract, pure tar, mixture of tar and lanolin, liquid paraffin containing tar, olive oil, or liquid paraffin, in the doses of from 0.3 to 0.5 cc., into the mammary glands; this injection was made once or twice a month. The animals which died after one or two injections are excluded. This development of epithelioma in 12.23 per cent of the animals injected might be considered a high average, especially when one recalls the fact that spontaneous mammary carcinoma seems to be very unusual.