1. Moderate or marked ovarian enlargement has been observed in 76 per cent of rabbits which survived double suprarenalectomy over 30 days.
2. The ovarian enlargement consists essentially of an hypertrophy of the interstitial cells.
3. The hypertrophy of the interstitial cells is a compensatory reaction and adds further data to the functional interrelation between the suprarenal cortex and the interstitial cells.