a crystalline body, present in small quantity in the urine of man and most mammals. Combined in the form of urate of ammonia, it is the chief constituent of the urine of birds and reptiles, forming the white part. Traces of it are also found in the various organs of the body. It is likewise a common constituent, either as the free acid or as a urate, of urinary or renal calculi and of the so-called gouty concretions. From acid urines, uric acid is frequently deposited, on standing in a cool place, in the form of a reddish yellow sediment, nearly always crystalline. Chemically, it is composed of carbon, hydrogen, nitrogen, and oxygen, , and by decomposition yields urea, among other products. It can be made synthetically by heating together urea and glycocoll. It was formerly called also , in allusion to its occurrence in stone, or calculus.