1. An extract has been prepared from the suprarenal cortex, which, when injected into rabbits, lowers the blood calcium to the extent of about 30 per cent.; the maximum fall occurs after 24 hours, and returns to normal in about 48 hours.
2. The extract prepared from the suprarenal cortex resembles that obtained from ovary and corpus luteum, both in physical characteristics, and in the production of a typical response on the part of the blood calcium.
3. It would appear that the hormone of the suprarenal cortex that is capable of lowering the blood calcium is very similar and possibly identical with the hormone of the ovary, having the same function.
4. A definite relationship has been established between the suprarenal cortex and the ovary, justifying the long-suspected connection between the two glands.