On the basis of analogies drawn from the behavior of zygadenine and its esters upon treatment with alkali, the existence of an isomeric, carbonyl-free cevagenine precursor was postulated. In a search for such a precursor, the amorphous fraction of commercial veratrine after removal of cevadine and veratridine was investigated. Fractionation using chromatographic procedures led to isolation of a new alkamine, protocevine, C27H43O8N, isomeric with cevagenine and cevine and a new ester alkaloid, cevacine, C29H45O9N, a monoacetate ester of protocevine. Cevacine yields protocevine upon methanolysis, and protocevine is isomerized to cevagenine by mild alkaline treatment. Acetylation of protocevine with acetic anhydride and pyridine yields protocevine triacetate and similar acetylation of cevacine affords the same triester. Acetylation of protocevine with acetic anhydride and perchloric acid yields anhydroprotocevine tetraacetate, and cevadine has been shown to give an analogous tetraester (anhydrocevadine triacetate) under the same conditions. Protocevine can be obtained from cevadine by methanolysis or by alkaline hydrolysis under very mild conditions. Very mild alkaline hydrolysis of veratridine also yields protocevine. It is proposed that protocevine, and not cevagenine, is the parent alkamine of cevacine, cevadine and veratridine. © 1953, American Chemical Society. All rights reserved.