892 GENERATION. 



Increases the activity of their movements, may pass through the uterus, into the Fallo- 

 pian tubes, and even to the surface of the ovaries. Precisely how their passage is 

 effected, it is impossible to say. We can attribute it only to the movements of the sper- 

 matozoids themselves, to capillary action, and to a possible peristaltic action of the mus- 

 cular structures, and must acknowledge that these points have as yet been incapable of 

 positive demonstration. 



In a very interesting memoir by Lott, which contains numerous observations bearing 

 upon the mechanism of conception, the experiments upon the behavior of the spermatozoids 

 under the microscope, in the presence of currents observed in the liquid between the two 

 plates of glass, develop some very curious points. It was shown, in these experiments, 

 that motionless spermatozoids followed the currents freely ; that, when the current in any 

 part of the field was strong, the moving spermatozoids were carried along with it ; but that, 

 when the current was comparatively feeble, spermatozoids endowed with active movements 

 made their way, as it were, against it. In reflecting upon these observations, it has 

 seemed to us that they offered an explanation, to a certain extent, of the passage of sper- 

 matozoids 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 ovaries toward 

 the uterus, would produce a feeble current. This current would naturally direct the 

 heads of the spermatozoids toward the interior, provided it were not too powerful, and 

 the movements of progression would therefore be from without inward. A little reflec- 

 tion makes it evident that, with a feeble current in the Fallopian tubes from within out- 

 ward, the spermatozoids, if the current were not strong enough to carry them with it, 

 could only progress in the opposite 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 inward. 



As regards the human female, we cannot give a definite idea of the time required for 

 the passage of the spermatozoids 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 experi- 

 mental 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. 



There are many elements of uncertainty in all investigations 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 obser- 

 vations 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 experiments upon mammals. He succeeded, however, in two observa- 

 tions upon rabbits, in which copulation took place after the period of heat and some time 

 after the discharge of ova. In both of these, he found ova at the superior extremity of 

 the cornua of the uterus, a position which he had found that the ova reached toward the 

 end of the third day. These ova, which were apparently advanced in decomposition, 

 presented no evidence of fecundation and were enveloped in a dense zone of albumen 

 which they had received from the Fallopian tubes. They were surrounded by sperma- 

 tozoids in active movement, but none had penetrated the adventitious albuminous cov- 

 ering. From these observations, the conclusion is deduced that fecundation can only 

 take place at the ovary or in the most dilated portion of the Fallopian tubes. When 

 we come to apply these observations to the human subject, we have, in confirmation of 

 them, only the abnormal phenomenon of abdominal pregnancy, which cannot occur 

 unless the ovum have been fecundated at the ovary, afterward falling into the abdominal 

 cavity instead of passing to the uterus. Still, the fact that conception may follow a 

 single intercourse occurring at any time with reference to the menstrual period throws 

 a doubt upon the theory that fecundation takes place only at or near the ovary ; and 

 another element of uncertainty is in the fact that we do not know positively that ovula- 



