The effects of nicotine on inseminated and artificially activated rana pipiens schreber eggs

SUMMARY The effects of nicotine on Rana pipiens Schreber eggs were studied, with particular emphasis on polyspermy induction. Treatment of Rana pipiens uterine eggs with nicotine was carried out as follows: 1. Simultaneous insemination and exposure to the drug (treatment eggs); or exposure to the drug followed by insemination (pretreatment eggs). 2. Exposure to the drug and activation by ES or pricking. 1. Pretreatment and treatment eggs deriving from the same clutch developed in some cases into normal embryos, in others into blastulae showing partial cytolysis or incomplete furrowing mostly at the vegetative hemisphere. In the not-clearly divided zones of the histologic sections, clusters of Feulgen-positive nuclei of different size were often observed. These nucleic clusters were similar to the polycarions appearing in incompletely cleaved blastulae described by HERLANT (1911) as deriving from polyspermic Rana fusca eggs. In addition, pretreatment and treatment eggs fixed within 1 hr after insemination,...