The results of this investigation have shown that the Calabar bean (Physostigma venenosum, Balfour) contains, in addition to some essential oil, resin, and other amorphous substances, the following compounds: Physostigmine, C15H21O2N3.-This alkaloid was found to be dimorphous, since two interconvertible modifications were obtained, melting at 86-87° and 105-106° respectively. The amount of alkaloid isolated was equivalent to 0.179 per cent. of the Calabar beans employed. Physovenine, C14H18O3N2, a new alkaloid, melting at 123°. Like physostigmine, it produces a powerful myotic effect on the pupil of the eye. Eseramine, an alkaloid melting at 245°. Calabarol, C23H36O4, a new dihydric alcohol (m. p. 245°), which Trifolianol, C21H36O4, a dihydric alcohol previously isolated from Stigmasterol, C30H48O, and sitosterol, C27H46O. Glycerides of behenic, stearic, palmitic, oleic, and linolic acids. A sugar yielding d-phenylglucosazone (m. p. 205°). In the course of the present investigation no evidence has been obtained of the presence in Calabar beans of the alkaloid designated by Ogui (loc. cit.) as "isophysostigmine," or of the "eseridine" of Böhringer & Söhne (loc. cit.).