FERTILITY 611 



a syringe into the vagina, and draw up into it some of the 

 seminal fluid which is caused to collect in a depression or pocket 

 made in the vaginal floor by the pressure of the finger tips. 

 The same mare can then be inseminated by injecting the fluid 

 so obtained into the uterine cavity, or the semen can be utihsed 

 for impregnating other mares. Another method is to collect 

 the semen in gelatine capsules which are placed in the vagina 

 before coitus, and then, when they have been filled, to close 

 their hds and insert them in the interior of the uterus, where 

 the heat of the body gradually melts the gelatine and sets free 

 the spermatozoa. By such means as this several mares may 

 be impregnated as a result of one service by a stalhon. In some 

 cases pieces of sponge have been employed instead of gelatine 

 capsules. In transferring semen from one animal to another 

 it is of considerable importance to preserve a moderate degree 

 of warmth ; otherwise the spermatozoa are liable to die as a 

 result of exposure before injection has been effected. 



Artificial insemination has been of considerable use also in 

 remedying sterility in cows as well as in dogs.^ 



Several investigators by employing artificial insemination 

 have been successful in getting crosses between animals be- 

 longing to varieties in which the disparity in size is so great 

 that coitus between them is difficult or impossible. Thus, 

 Plonnis ^ in 1876 successfully inseminated a lap-dog with the 

 semen of a setter, and obtained a pup which in most of its points 

 resembled its father. Allbrecht^ performed a similar experi- 

 ment and obtained a similar result. More recently Heape * 

 has described some experiments carried out by MiUais, in which 

 bloodhounds were inseminated with spermatozoa obtained 

 from Basset hounds (a much smaller breed), fitters of cross-bred 

 pups being produced. 



Iwanoff ° has recorded an experiment in which he successfully 

 inseminated a white mouse with the spermatozoa of a white rat. 



' See Huish, loc. cii. 



^ Plonnis, " Kunstliche Befruchtung einer Hunden," &c., Inaug. -Dissert., 

 Eostock, 1876. 



' Allbreoht, "Kunstliche Befruchtung," Wochenschr. f. Thierhdlkunde 

 und Viehzucht, Jahrg. xxxix. 



* Heape, "The Artificial Insemination of Mammals," Proc. Roy. Soc, 

 vol. Ixi., 1897. ^ Iwanoff, loc. cit. 



