The improved determination of iron in serum.

Cleaning the Apparatus After each series of examinations the reaction chamber is cleaned with a 1%0 solution of triethanolamine stained with phenol red; this is followed by lactic acid water. When the mercury becomes dirty and begins to form little balls in the reaction chamber I to 2 ml. of 200,, ferricyanide solution is introduced into the reaction chamber and shaken well. Lactic acid and water follow as above. Improvements In a later model of the apparatus we introduced a magnetic stirrer,* which permitted vigorous mixing of the contents of the reaction chamber without the need of manual shaking. A twisted piece of stainless steel wire was enclosed in the reaction chamber and set into violent motion by means of a vibrator.