The first clinical studies on the urinary excretion of sodium ferrocyanide as a criterion of glomerular efficiency were reported in 1934.1 It was then shown that the curves for the excretion of this salt by normal persons are characteristic and have but little variation. In the succeeding four years additional data have been obtained, and these continued studies have further clarified the application of the test.
There has been no significant change in the technic proviously reported. Ampules of sterile dry pure sodium ferrocyanide containing 0.5 Gm. of the hydrated salt, or about 0.25 Gm. of the anhydrous salt, were employed. Ferrocyanide salts might be decomposed by the gastric acid if taken orally, but on slow intravenous injection no evidences of toxic effects have been observed.The contents of one ampule are dissolved in 10 cc. of sterile distilled water and administered by slow intravenous injection. It is