1. A poisonous organic base (a ptomaine) formed in the decomposition of protagon with boiling baryta water, and in the putrefraction 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.