0 Yields are based on the intermediate succinic acids.* Analytical data were determined by Mr. Charles E. Childs, Miss Virginia Pawlik and Mrs. Geraldine Koch of this Laboratory. a 4+/125 indicates that a group of five rats is completely protected against a convulsant dose of metrazol by 125 mg./kg. PDm indicates the dose in mg./kg. necessary to protect 50% of the animals (mice) against electrically-induced convulsions. See ref. 11 for a more ...