SPERMATOGENESIS— INSEMINATION 177 



Leeuwenhoek,'- and subsequently Pr6vost and Dumas/ state that 

 they found moving sperms in the internal genital organs of female 

 rabbits and dogs eight days after coition. Bonnet ^ says that he 

 observed motionless sperms, which, therefore, were probably dead, 

 but had not yet undergone disintegration, in a bitch seventeen and a 

 half days after coition. In a series of experiments upon the 

 longevity of the spermatozoon in the rabbit, it was found that these 

 cells can survive in the vasa deferentia for at least ten days after 

 the removal of the testes, but that they die before the end of 

 thirteen days.^ 



Spallanzani* stated that a hen can lay fertilised eggs twenty 

 days after impregnation, but it would appear that there is some varia- 

 tion. Elford^ states that a drop in the fertility of the eggs takes 

 place on the ninth day, that 50 per cent, of the eggs are fertile on 

 the tenth day, 16 per cent, on the fifteenth, and after that none at 

 all. Philips^ and Kaupp^ have made confirmatory observations. 

 The first fertile egg in fowls is said to be laid three or four days after 

 mating. In the turkey one insemination is sufficient to fertilise a 

 whole batch of eggs. Riddle ^ found the sperms of the ring-dove 

 retained their fertilising power for nearly eight days. 



Strassmann® has recorded a case in which human spermatozoa 

 survived in the female generative passages for a week after coition. 

 Bossi ^^ refers to a similar instance where the sperms lived for over 

 twelve days. In another case described by Duhrssen,^! living 

 spermatozoa were found in a woman who stated that coition had 

 not been experienced for three and a half weeks. 



In many species of bats, as already mentioned, copulation takes 

 place in autumn and ovulation in the following spring, so that the 

 spermatozoa retain their vitality while stored up in the uterus 

 during the hibernating period. Sperms obtained from the females 



' See Waldeyer's article in Hertwig's Handbuch der Entwicklungslehre, 

 Jena, 1903. 



2 Bonnet, "Giebt es bei Wirbelthieren Parthenogenesis," Merhel und 

 Bonnet's Ergehnisse d. Anat. u. Entwick., vol. ix., 1900. 



^ Marshall and Jolly, "Contributions to the Physiology of Mammalian 

 Reproduction : The CEstrous Cycle in the Dog," Phil. Trans., B., vol. cxcviii., 

 1905. 



* Spallanzani, loc. cit. 



5 Elford, Canada Exp. Farms Report, 1916. 



" Philips, Jour. Amer. Assoc. Instr. and, Invest. Poultry Hnshandry, 1918. 



^ Kaupp, North Canadian Exp. Stat. Pull., 1915. 



* Riddle and Behre, " Studies on the Physiology of Reproduction in Birds : 

 IX. On the Relation of Stale Sperm to Fertility and Sex in Ring-doves," 

 Amer. Jour, of Physiol., vol. Ivii., 1921. 



" Strassmann, Lehrhuch der gerichtliohen Medizin, 1^95. 



'" Bossi, "Etude Clinique et Exp6rimentale de FEpoque la plus favorable 

 a la FIcondation de la Femme," Rivista di Ohstet. e Oinecol., 1891. 



'1 Duhrssen, " Lebendige Spermatozoen in der Tube," Centralhl. f. Oynak., 

 1893. 



