urea (u-re'ah)

Carbamid, or rather carboxyl diamin, CO(NH2)2, the chief solid constituent of the urine and the principal excretory product containing nitrogen. It is also present in the blood, bile, liver, and muscle. It forms long, colorle , prismatic soluble in crystals, water and melting at 1320 in alcohol. C, It acts as a base, forming addition compounds 852 with acids and their salts and with metallic oxids. It is decomposed by heat and moisture, and more slowly by the action of bacteria into normal ammonium carbonate. This proce takes place in the urine, constituting its so-called alkaline fermentation and giving to stale urine its peculiar strong ammoniacal odor. U. is also decomposed into cyanogen compounds (cyanuric acid biuret) by the action of dry heat. It is remarkable as being the first organic body that was prepared artificially; Wohler having accomplished this in 1828 by making the isomeric cyanate of ammonium, and then transforming the latter into u. by allowing it to stand in an alcoholic solution. It has been used medicinally in pulmonary tuberculous disease, and it is an active non-toxic diuretic, which is rapidly eliminated, u. in urine, Hiifner's method to determine amount of; see in appendix, page 895. u. in urine, to determine amount of; see in appendix, page 895. u. nitrate. A crystalline compound used to isolate urea from the urine. [Gr., our on, urine.]