Uricase was found in the livers of all the animals examined (horse, ox, pig, sheep, dog, cat, rabbit, guinea pig, rat, mouse hedgehog, bat (Eptesicus serotinus), frog (Rana esculenta), carp, crayfish, freshwater mussel (Anodonta mutabilis), and in the kidneys of oxen, pigs, dogs, rats and frogs. It was absent from the kidneys of the other animals and from all organs other than the liver and kidney of all animals examined.