342 GENERATION. 



passage of spermatozoids in the Fallopian tubes toward the 

 ovaries. It is undoubtedly true that the ciliary motion in 

 the Fallopian tubes, in which the direction is from the ova- 

 ries toward the uterus, would produce a feeble current. 

 This current would naturally direct the heads of the sperma- 

 tozoids toward the interior, provided it were not too power- 

 ful, and the movements of progression would therefore be 

 from without inward. A little reflection makes it evident 

 that, with a feeble current in the Fallopian tubes from with- 

 in outward, the spermatozoids, if the current were not strong 

 enough to carry them with it, could only progress in the op- 

 posite direction ; but this cannot explain the passage of the 

 spermatozoids through the uterus itself, where, according to 

 the best authorities, the ciliary current is from without in- 

 ward. 



As regards the human female, we cannot give a definite 

 idea of the time required for the passage of the spermato- 

 zoids to the ovaries or for the descent of the ovum into the 

 uterus; and it is readily understood how these questions 

 are almost incapable of experimental investigation. We 

 know, however, that spermatozoids reach the ovaries, and 

 they have been seen in motion on their surface seven or 

 eight days after connection. 1 



There are many elements of uncertainty in all investiga- 

 tions as to the usual or the normal situation of fecundation. 

 As the spermatozoids are found in movement in all parts of 

 the generative passages, the question resolves itself into that 

 of the duration of vitality of the ovum after its discharge ; 

 and here we must rely exclusively upon observations made 

 on the inferior animals. Coste, who demonstrated beyond a 

 doubt that fecundation occurs in fowls at or very near the 

 ovary, recognized fully the difficulties attending similar ex- 

 periments on mammals. lie succeeded, however, in two ob- 

 servations on rabbits, in which copulation took place after 

 the period of heat and some time after the discharge of ova. 



1 KOLLIKER, Elements dhistologie humaine, Paris, 1868, p. 682. 



