no evidence has been obtained that tar , benzpyrene , methylcholanthrene , arsenical preparations , or benzene , -which produces tumors of rabbit skin occasionally ( 1 ) , -bring about any neoplastic changes peculiar to them individually when they act upon cells of a single sort , those of the stratum germinativum of rabbit epidermis .
C0221925
stratum germinativum
C0014520
epidermis