OVARIAN SECRETION AND TUMOR INCIDENCE.

(1) Non-breeding reduces tumor incidence in mice and delays the time of tumor appearance (207 mice used). (2) Two hundred and ten female mice castrated at 28-35 days behave much the same as non-breeding females. (3) Two hundred and forty-one males castrated at 28-35 days did not develop tumor, thus resembling non-castrated males. (4) Spontaneous tumors, never obtained in thousands of normal males of the stock used, may develop in castrated males which have received subcutaneous transplants of ovarian tissue (210 operated-four tumors).