(for acetonemia) a few drops of plasma are placed in a small test tube. Enough dry powdered ammonium sulfate is added to supersaturate, so that at the end of the test there will still be some of the solid sulfate in the bottom of the tube. A couple of drops of a fresh solution of sodium nitroprusside are next added and shaken, and finally 1 or 2 drops of diluted ammonia solution. On shaking, a purple color develops, a little more slowly than in the case of urine. The intensity of the color indicates the degree of acetonemia.