paper he discussed the results whim had been obtained from his studies of the adrenal gland. The results he obtained are probably best told in his own words: -"To see whether the adrenal cortex contains any such reducing agent the gland was cut with a knife into halves-which were immersed in a 0. 4% AgN0 solution. In a few minutes the cortical part 3 was seen to darken through the deposition of reduced metallic silver. In a quarter of an hour the cut surface of the cortex turned completely black while the medulla remained largely uncoloured. The black colouration ends towards the medulla with a sharp margin, which corresponds to the anatomical margin between the medulla and cortex. Like the medulla, other organs, such as brain, liver and muscle remain practically uncoloured. " When the gland was immersed in a mixture of potassium iodate and acetic acid-a reagent for adrenalin, the medulla became violet in colour and the cortex remained colourless. SZENT-GYORGYI therefore came to the conclusion that: -"The adrenal cortex therefore, contains some specific highly reducing agent which can be no arte fact, since its action is produced in the almost fresh material. " Methyl alcohol extracts of the cortex reduced neutral silver nitrate almost instantaneously and when the portions of the interrenal glands of Elasmobranm fishes were treated with silver nitrate solutions they too went black-so that it appeared that this highly reducing factor was a funda mental constituent of adrenal tissue."