{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, {C5H4N4O3}, 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.