184 THE PHYSIOLOGY OF REPRODUCTION 



ficial insemination upon a woman (previously sterile), 1 but it has 

 since been successfully adopted by various medical men, the 

 method being to inject the spermatozoa through the os into the 

 cavity of the uterus (see p. 609). 



With those animals whose ova are normally fertilised outside 

 the body, artificial insemination is a still simpler process. 

 Spallanzani was the first to show that the eggs of various 

 species of Amphibia could be fertilised by the application of 

 fluid obtained from the testes or seminal vesicles of the male, 

 and that the frogs and newts which were generated by this 

 means in no way differed from those produced in nature. 

 Spallanzani was also successful in artificially fecundating the 

 eggs of the silk- worm moth. 



Artificial impregnation of fish ova was first employed by 

 Jacobi, 2 and the method which he adopted is practically the 

 same as that habitually practised at the present day for 

 stocking water-courses with fish. 



The vitality of the spermatozoon appears to vary widely in 

 the different species of animals. 



Leeuwenhoek, 3 and subsequently Prevost and . Dumas, 3 

 state that they found moving sperms in the internal genital 

 organs of female rabbits and dogs eight days after coition. 

 Bonnet 4 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. 6 



Spallanzani 6 cites the fact that a hen can lay fertilised eggs 

 twenty days after impregnation by a cock. 



1 Home, " An Account of the Dissection of an Hermaphrodite Dog," I'hil. 

 Tram., 1799. 



2 See Giinther, Introduction to the Study of Fixhcs, Edinburgh, 1880. 



3 See Waldeyer's article in Hertwig's Handbuch der k'ntu-wklungslehrc, 

 Jena, 1903. 



4 Bonnet, "Giebt es bei Wirbelthieren Parthenogenesis," Merkcl und 

 Bonnet's Ergebniese d, Anat. u. Entumk, vol. ix., 1900. 



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

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

 1905. 6 Spallanzani, loc. cit. 



