Studies in the sulphur metabolism of the dog

IN the course of some work on the metabolism of pyrimidines Stekol and Cerecedo [1931] observed that a dog did not excrete any neutral sulphur in its urine after the administration of isobarbituric acid. They found that iso- dialuric acid and formyloxaluric acid had a similar effect. We have two reasons for distrusting these conclusions. Firstly, the complete elimination of neutral sulphur from the urine could only occur if the pyrimidine were altering the course of metabolism of a large number of different substances. It seems to us that such an effect is very unlikely. Secondly, Cerecedo himself [1930], in some earlier work on the metabolism of isobarbituric acid, did not find any such effect.