Ga*lac"tin (?), n. [Gr. &?;, &?;, milk. Cf. Lactin.] (Chem.) (a) An amorphous, gelatinous substance containing nitrogen, found in milk and other animal fluids. It resembles peptone, and is variously regarded as a coagulating or emulsifying agent. (b) A white waxy substance found in the sap of the South American cow tree (Galactodendron). (c) An amorphous, gummy carbohydrate resembling gelose, found in the seeds of leguminous plants, and yielding on decomposition several sugars, including galactose.