The mercurial diuretic salyrgan produced 3 distinct types of reduction in renal blood flow and glomerular filtration. The reduction in glomerular filtration and renal plasma flow produced by hemorrhage or clamping ofthe aorta above the renal arteries resulted in a marked decrease in.the e: ffectiveness of the mercurial as a diuretic. The reduction in glome- rular filtration is probably the more important factor in this refractori- ness to the mercurial. In the light of these findings and others brought out in the discussion, the refriwtory state of the kidney to mercurial diuretics has been discussed. Bibliography. 1 WALKER, A. M., C. F. ScaMIDT, L. A. ELSON and C. G. JoHNSTON: Amer. 2 J. Physiol. 118, 95 (1937).- SMITH, H. W.: The Kidney, Structure and Function in Health and disease. New York: Oxford University Press 1951. Page 892. - 4 3 MoELLER, K. 0.: Arch. exper. Path. u. Pharmakol. 148, 67 (1930). - FARAH, 5 A., and G. MARESH: J. of Pharmacol. 92, 73 (1948). - DuGGAN, J. J., and R. F.