the fertilizing capacity of fowl sperm suspensions.

1942. Fertility in the male domestic fowl. THE embryo of the chicken has been demonstrated to be resistant to. limited periods of exposure to sub-freezing temperatures by Moreng and Bryant (1954a, b). When the ambient tempera-ture was held at — 10°F. it was found that the age of the embryo as well as the length of the exposure period were closely re-lated to mortality of embryos. The early embryo was the most resistant to expo-sure up to a period of 125 minutes, when nearly 100 percent mortality was recorded for all age groups. Appearance of the embryo after death suggested that the direct cause of death was hemorrhaged tissue probably resulting from ice crystal formation. EXPERIMENTAL Ice crystal formation commences in the chicken egg at approximately 28°F. and ' then during the solidification process the internal temperature of the egg remains at approximately 30°F. (Moreng and Shaff-ner, 1951). Eggs were exposed in this study to an ambient temperature o