The Survival of the Spermatozoon in the Domesticated Fowl

In the large majority of animals which have internal fertilisation the effective length of life of the spermatozoon within the body of the female is extremely short. In no mammal is it known to extend from one oestrous period to another. A certain number of more exact determinations have been made. In rabbits, for example, fertilising capacity is retained for about 30 hours (Hammond and Asdell, 1926), and in sheep fertility diminishes presumably from death of the spermatozoa about 27 hours after mating (McKenzie and Phillips, 1930). Data on the survival of motility, which it is to be supposed coincides approximately with fertilising capacity, has been collected by Hammond and Marshall (1925, chap. 6) and Yochem (1930), and the latter found 41 and 17 hours’ survival in the uterus of the guinea pig and rat respectively. However, there are also many known instances of long survival, especially in the invertebrates. In the queen bee, for example, sperm may be stored 7 years and still retain its fertilising power (Bishop, 1920; Courrier, 1921), and in other Hymenoptera spermatozoa may be stored during hibernation or throughout the whole period of egg-laying. Many invertebrates have spermathecae in which spermatozoa are stored presumably for considerable periods. Among the vertebrates prolonged survival is much less common. Some teleosts which have internal fertilisation store spermatozoa for long periods (van Oôrdt, 1928). In some bats, which have their mating season in the autumn and in which the follicles do not ripen till the following spring, the spermatozoa remain alive within the female during the winter (Courrier, 1924; Redenz, 1929). In the male mammal spermatozoa may also be stored for a considerable time in the epididymus (Benoit, 1925, 1926 ; Hammond and Asdell, 1926; Redenz, 1924, 1925, 1926; Young, 1929, 1929 a, 1931). In all these cases of long survival the spermatozoa are stored under what are probably very favourable conditions, of which perhaps the most important is the dense concentration of the sperm-suspension. This is universally characteristic. It has long been known that spermatozoa survive better in concentrated suspension (Gemmill, 1900; Cohn, 1918). Gray (1928, 1928 a, 1931) provides the most likely explanation, having shown for the sea-urchin that dilution activates the sperma-tozoon and that the rate of senescence is an inverse function of the activity.