SPERMATOGENESIS— INSEMINATION 185 



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 

 hved for over twelve days. In another case described by 

 Diihrssen,^ Uving 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 vitaUty while stored up in 

 the uterus during the hibernating period. Sperms obtained 

 from the females at this time are dormant, but regain their 

 vitality on the apphcation of warmth.* 



The spermatozoa of some warm-blooded animals will stand 

 considerable variation in temperature and still retain their 

 vitality. Thus they have been known to hve for many hours at 

 ordinary room temperature ; but, undoubtedly, ejected sperms 

 tend to survive longest if kept at body temperature. Heape ^ 

 states that some seminal fluid of a dog was sent to him by post 

 in a glass tube, and on being examined eighteen hours after it 

 was obtained, fully half the spermatozoa were found to be 

 active and vigorous, while increased warmth stimulated to 

 activity those which showed signs of sluggishness but did not 

 revive the remainder. 



In the experience of the writer, horses' spermatozoa die more 

 easily if exposed to cold. Chelchowski,* in describing the 

 methods adopted in the artificial insemination of mares, lays 

 stress upon the necessity of keeping the seminal fluid warm, 

 and states that, if this is done, it is possible to keep the sperms 

 alive for twenty hours. 



The case of bats, which has been referred to above, has a 

 parallel in certain cold-blooded animals. Thus, according to 



' Strassmann, Lehrbuch der gerichtlichen Mediz'n, 1895. 



* Bossi, "Etude Clinique et Exp^rimentale de I'Epoque la plus favorable 

 k la F^condation de la Femme," Bivista di O'satet. e Ginecol., 1891. 



' Duhrssen, "Lebendige Spermatozoen in der Tube," GentraUl. f. Gyndk., 

 1893. 



* See Eimer and other references given on page 136. 

 " Heape, loc. cH. 



' Chelohowski, Die Ster'.litdt des Pf&rdes, Wien, 1894. 



