The effect of two pesticides, Miedzian 50 and Gesagard 50, on the development of tadpoles of Rana temporaria.

Tadpoles of the frog, Rana temporaria, in two developmental stages were subjected to the action of aqueous suspensions of two pesticides--Miedzian 50 and Gesagard 50. The changes caused by these substances pertain chiefly to the alimentary canal, brain, and muscles, and are connected with the developmental stage of the animals. Miedzian 50 caused a partial sytolysis in the cells of the intestinal epithelium and the parenchyma of the liver. Gesagard 50 was more toxic; under its action strong degenerative changes were obtained in the alimentary canal and the brain. Also, disorders in the development of tadpoles were observed. These consisted in a partial inhibition of growth and a retardation of the process of completion of the operculum as compared with control animals.