Medicinal Arsenic Poisoning and Lung Cancer

methicillin or cloxacillin destroy these more rapidly than when cultured in broth. Sensitive strains cannot, of course, grow in high concentrations of these penicillins and there- fore cannot be tested under comparable conditions. However, when such strains are pre-induced they too destroy methicillin and cloxacillin more rapidly than organisms cultured in broth. With all four strains of staphylococci used here, whatever method was used for inducing penicillinase, the rate of hydrolysis of methicillin and cloxacillin was a small fraction (1 % or less) of the rate of hydrolysis of benzylpenicillin under comparable condi- tions. So far there is no evidence in these strains of a specific " methicillinase " or " cloxacillinase."