The Purine Metabolism of the Dalmatian Coach Hound

Recently Benedict1 reported the’ observation that the Dalmatian breed of coach hound exhibits a marked peculiarity in its purine metabolism, to t,he extent that it excretes large amounts of uric acid, even when on a purine-free diet. This peculiarity was exhibited by four Dalmatians examined, but a fifth, “obviously not of very pure breed,” did not eliminate much uric acid. That a single species of dog should exhibit this characteristic is remarkable, especially in view of the fact that the only other mammals that excrete uric acid in any considerable amounts are man and the anthropoid apes. The Dalmatian coach hound, however, differs also from man and the anthropoids, in that it excretes allantoin in considerable amounts; i.e., from one-half to two-t’hirds as much allantoin as uric acid. Hence the Dalmatian is unique in respect to purine metabolism. This fact is of more than academic interest, for it gives us for the first time a laboratory mammal that excretes considerable amounts of uric acid, and hence serves as a possible medium for experimentation under conditions somewhat resembling those obtaining in the human subject,. Benedict has already employed the Dalmatian for such investigations. Since other species of dogs differ so radically from the Dalmatian in respect to purine metabolism, there is also opened a most interesting field of investigation in the inheritance of a metabolic process, as exhibited by the products of mating of Dalmatians with other species. Having found an apparently pure blooded Dalmatian in one of our laboratories it seemed desirable to determine whether it was