Tumours Produced in Hamsters by Benzpyrene

meantime by Gye and Foulds ( 1) no observations on this animal have been recorded. We used the Syrian, or golden, hamster ( Cricctus auratus), of which one strain is bred in our laboratory. Animals weighing about 80 gm. were injected subcutaneously, in the abdominal region, with benzpyrene Meurice, 0.25 C.C. of a solution in lard, every three or four weeks, the injections being interrupted as soon as a tumour became apparent. Forty animals were treated between Nov. 6, 1935, and April 28, 1938. Nine died within the first three months of treatment. Of the 31 remaining, 29, or 93 per cent, developed tumours. The earliest beginning of a tumour can not usually be established with certainty, for infiltrations forming after injection may be misleading. Definite tumours may appear after two months, but the average period is three months.