-A tumour initiating dose of ethyl carbamate was administered to mice by subcutaneous injection together with a dose of one of the homologous esters or an ethyl N-alkyl derivative. The homologues used were the methyl, n-propyl and n-butyl esters, and the derivatives were the N-methyl, N-ethyl and N-n-propyl ethyl esters. The mice were then given promoting treatment with croton oil for 28 weeks....
