The effects of methylmercury compounds on the skin (in vitro) of the leopard frog (Rana pipiens)

1. 1. Leopard frogs readily survive injections of large amounts of dimethylmercury or methylmercuric chloride. 2. 2. The short-circuit current and P.D. across the skin (in vitro) were not changed by dimethylmercury (10^-3 M) but were reduced by methylmercuric chloride (10^-4 M). The latter was only active when present in the epidermal bathing media. 3. 3. The electrical resistance rose initially, then declined. 4. 4. These responses were only modified when BAL was added prior to the drug. The effects were irreversible. 5. 5. The action of vasotocin on osmotic water transfer was antagonized by methyl-mercuric chloride and the O₂ consumption was depressed. Dimethylmercury (10^-3 M) was without action.