CORPUS LUTEUM EXTRACTS AND OVULATION IN THE RABBIT

1. A substance, or substances, can be extracted in the cold from the corpus luteum of the cow, in the fresh or desiccated state, which inhibits ovulation in the rabbit, if injected intravenously in sufficient dosage. 2. Long-continued dosage with these extracts may be correlated with more or less marked degenerative changes in the ovary, and to a progressively less degree in the liver and adrenal glands, none being observed in the kidney. 3. In the experimental animals in which the point was tested, ability to ovulate was not recovered in three months from the cessation of treatment. 4. The fertility of the male controls was not impaired by parallel treatment. 5. The toxic effects produced were insufficient to cause convulsions or death.