Alkaloid

n. [From alkali and Gr. εἶδος, form.] (Chem.) A salifiable base existing in some vegetables as a proximate principle, and belonging to different series. Gregory.

☞ Alkaloids all contain nitrogen, and, with this, carbon, hydrogen, and oxygen are often, but not always, present. They include many of the active principles in plants; thus, morphine and narcotine are alkaloids of opium.