Ovulation of the Excised Ovum of the Hen

PHILLIPS and Warren (1937), in studying ovulation in the hen, de-scribed ovulation of 6 excised ovarian fol-licles clamped at the stalk to maintain turgidity. Four of these were returned to the body cavity where they ovulated, and 2, kept moist with Ringer's solution, ovu-lated outside the body. Phillips and Warren also observed the ovulation of 40 unsevered follicles in celiotomized hens. All ovulations recorded by these authors occurred in follicles expected to rupture within about an hour following initial observations. Follicles removed from the ovary about an hour before the time of expected rupture, and maintained thereafter in saturated atmospheres or in approxi-mately isotonic solutions at 100°F., have been found capable of ovulation inde-pendently of any means of increasing turgidity (unpublished results from this laboratory). These exploratory tests yielded, however, only 14 completed ovu-lations from 47 follicles. The present study describes a simple and dependable technic by which ovula-tion of the excised follicle of the hen may be observed directly, and by which clean, intact yolks, ovulated in vitro, may be ob-tained. * Data on the interval from lay to * The modified procedure for obtaining yolks in vitro was developed in connection with an investiga-tion of the site of fertilization in the hen, and has been described previously by Olsen and Neher (1948). The main change in procedures was to main-tain the follicles at a temperature of 107CF., rather than at 100°F. as in previous work. succeeding ovulation of excised follicles from autopsied hens and follicles of celi-otomized hens are also given, observations in the latter connection confirming, in some respects, previous work by Warre