(Science: biochemistry) The final product of nitrogenous excretion in animals that require to conserve water, such as terrestrial insects or have limited storage space, such as birds and their eggs. Uric acid has very low water solubility and crystals may be deposited in, for example: butterflies wings to impart irridescence.
Uric acid, 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 lithic acid, in allusion to its occurrence in stone, or calculus.