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- 

 formed 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 |] has detected the spermatozoa in a living state in 

 the uterus and Fallopian tubes eight days after connexion. 



Lastly, Bischofflf and Martin Barry ** have observed the 



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



j Leeuwenhoek signalised the discovery of the living spermatozoa in 

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

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

 at eandem mediante bono microscopic, summae mese voluptati immen- 

 sam viventium animalculorum multitudinem ; semen nempe canis mas- 

 culum contemplabar. His peractis, dictain aperiebam tubam, in fine suae 

 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 

 copiaiii'Observavi. . . . Materiam qua matrix concita est, observans 

 majorem adhuc viventium animalculorum copiam deprehendebam. 



Annales des Scien. 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. 



