Neu"rine (? or ?), n. [Gr. &?; a nerve.] (Physiol. Chem.) A poisonous organic base (a ptomaine) formed in the decomposition of protagon with boiling baryta water, and in the putrefaction of proteid matter. It was for a long time considered identical with choline, a crystalline body originally obtained from bile. Chemically, however, choline is oxyethyl- trimethyl-ammonium hydroxide, while neurine is vinyl-trimethyl- ammonium hydroxide. [Written also neurin.]