THE SEMEN. 199 



proportion to the activity of the reproductive function, and 

 this again is dependent to a great extent upon the constitu- 

 tional powers as well as upon the mode of life. 



The activity then of the reproductive faculty in man is in 

 many cases a good test of health. 



The above few facts favour the idea of the essentiality of 

 the spermatozoa ; others however, of a stronger kind, still 

 remain to be mentioned. 



Wagner has instituted some most interesting inquiries in 

 reference to the condition of the spermatozoa in male 

 hybrids, and especially in male hybrid birds, and he finds, 

 that in them the characteristic animalcules are either al- 

 together wanting, or occur but in small numbers, and are ill- 

 foraied and ill-conditioned ; the hybrids in which the seminal 

 animalcules have been thus found to be absent or degenerated, 

 have been ascertained to be incapable of having offspring.* 



Again, Leeuwenhoekf discovered living seminal animalcules 

 in the uterus and Fallopian tubes of bitches seven days after 

 connexion. J 



Prevost and Dumas have more recently made the same 

 observations at the same length of time after intercourse. 



Siebold I) has detected the spermatozoa in a living state in 

 the uterus and Fallopian tubes eight days after connexion. 



Lastly, BischofFIF and Martin Barry ** have observed the 



* Loc. cit. pp. 3034. t Opera omnia, p. 150. 



| Lceuwenhoek signalised the discovery of the living spermatozoa in 

 the uterus and Fallopian tubes, in the following words : " Kudo conspi- 

 ciens oeulo, nullum masculum semen canis in ea esse dicere debuissem ; 

 at eandem mediante bono microscopic, summae meae voluptati iinmen- 

 sam viventium aniinalculorum multitudinem ; semen nenipe canis mas- 

 culum contemplabar. His peractis, dictam aperiebam tubam, in fine siue 

 crassitudinis, ac ibidem quoque magnam seminis masculi canis contem- 

 plabar copiam, quod semen illic vivebat, et hoc modo quoque cum dextra 

 egi tuba, ac in eadem quoque immensam seminis viventis canis masculi 

 copiam observavi. . . . Materiam qua matrix concita est, observant 

 majorem adhuc viventium aniinalculorum copiam deprehendebam. 



Annales des Scicu. Nat. t. iii. p. 122. 



|| Muller, Archiv. p. 16. 1841. ^[ Wagner's Elements, p. 66. 



** Researches in Embryology, Second Series, Phil. Trans, p. 315. 

 1839. 



