The amorphous fraction of the extract of the adrenal cortex which has the greatest effect on the metabolism of certain inorganic electrolytes so far has resisted all attempts at crystallization or separation into pure components. The high lability of the material has been the main reason for lack of success in this and other laboratories.Perhaps the most striking property of the amorphous fraction is its high solubility in water compared with that of any of the numerous crystalline compounds already isolated from the adrenal cortex. This behavior led SUMMARY The preparation and properties of 16-ketotestosterone acetate are described.Rochester, Minn.