176 THE PHYSIOLOGY OF REPRODUCTION 



been the means of preserving for breeding purposes many valuable 

 animals which otherwise would have been discarded.^ 



Iwanoff^ has described experiments in which pregnancy was 

 induced in rabbits and guinea-pigs by the artificial injection of 

 testicular fluid into the female generative passages. The same 

 investigator states that. he induced hybridisation between a male rat 

 and a female mouse by artificially inseminating the latter (see p. 649, 

 Chapter XIV.). 



He has shown, further, that the spermatozoa retain their vitality 

 'Sufficiently long to admit of their being employed successfully in 

 artificial insemination if they are kept in solutions of various salts 

 (sodium chloride, sodiuin carbonate, etc.) or in serum instead of in 

 the secretions of the accessory generative glands. Hunter appears 

 to have been the first ta practise artificial insemination upon a 

 woman (previously sterile),^ 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. 647). 



- 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,* 

 and the method which he adopted is practically the same as that 

 habitually practised at the present day for stocking water-courses 

 witli fish. 



The vitality of the spermatozoon appears to vary widely in the 

 .different species of animals. 



' For references to particular experiments see Heape, "The Artificial 

 -Insemination of Mares," Veterinarian, 1898 ; also a booklet published by 

 Huish (The Cause and Remedy of Sterility in Mares, Cows, and Bitches, 

 London, 4th Edition, 1899), in which a large number of cases are described 

 in which artificial insemination was successfully carried out ; also Iwanoff, 

 ,"De la Fecondation Artificielle chez les Mammifferes," Arch, des Sciences 

 Biologiques, vol. xii., 1907. The last-mentioned paper contains an account 

 of a very large series of experiments on horses, cows, and sheep, with a 

 full description of the practical methods employed, and a very complete 

 account of the literature of the subject. 



2 Iwanoif, "La Fonction des Vfesicules sfeminales, etc.," Jour, de Phys. et de 

 Path, gen., vol. ii., 1900. 



^ See Home, "An Account of the Dissection of an Hermaphrodite Dog," 

 Phil. Trans., 1799. 



■* See Giinther, Introdnction to the Study of Fishes, Edinburgh, 1880. 



