THE STUDIES on the concentration of chloride, urea, glucose, uric acid and ammonia nitrogen in palmar sweat1were made on pure sweat collected from the openings of sweat ducts on the palmar surface of the finger.1aThe analytic methods were such that the volumes of sweat collected were adequate for chemical study when the sweat was issuing from the ducts in either a profuse or an intermittent manner (fig. 1 of the article on urea by one of us [W. C. L., Jr.] and Osterberg1c): the so-called profuse and intermittent physiologic types of sweating. In our study on creatinine, it was observed that the volume of sweat which could be collected in the half-hour period of observation in most instances was not sufficient to allow accurate analysis of this constituent even when using the capillary tube colorimetric method of Bordley, Hendrix and Richards2adapted to the