GENERATION. 



465 



that this process may take place, in some in- 

 stances at least, in the upper parts of the Fal- 

 lopian tube, or even in the infundibulum. 



In the second place physiologists have en- 

 deavoured to argue respecting the place of 

 fecundation from the well-known fact that, 

 in the common fowl, turkey, and probably 

 some other birds, a single connexion with the 

 male serves to fecundate more than one ovum, 

 as, for example, in the common fowl twelve 

 or twenty ova ; and that, as there is usually only 

 one ovum in the progress of descent through 

 the oviduct at one time, we must conclude 

 either that the yolks or ovula are fecundated 

 by the rise of the seminal fluid to the ovary, 

 or that the seminal fluid remains somewhere 

 in the course of the oviduct, to be applied to 

 the ovum as it descends. If we exclude the 

 notions of an aura and sympathetic action, 

 the former of the above-mentioned views ap- 

 pears to us the most consistent with the facts 

 that have already come under our knowledge. 

 The notion entertained by T'abricius and others 

 that there is a receptacle for containing the 

 seminal fluid in the oviduct appears to be in- 

 correct ; and we rind it difficult to believe that 

 the seminal fluid can remain dispersed through 

 the oviduct, or confined in any particular part 

 of it and retain its power of fecundation, when 

 we consider the manner in which each yolk 

 descends from the ovary and receives in its 

 passage the various accessory parts constituting 

 the albumen and external coverings. Of 

 course, in supposing fecundation to take place 

 in the ovary, there remain two suppositions 

 which may be entertained regarding the mode 

 in which the seminal fluid gains the ovula ; 

 for it might either pass directly up the tube of 

 the oviduct, or be absorbed and take some cir- 

 cuitous course. 



In the third place, we are inclined to think 

 that in quadrupeds the ova must be already 

 fecundated before their arrival in the uterus, 

 that is, either in the neighbourhood of the 

 ovary or in the tubes, for this reason, that at 

 the time when the ovum first arrives in the 

 uterus, it has already become considerably 

 enlarged, and has undergone some of the 

 changes of development;* and when we con- 

 sider how very regular and progressive these 

 changes have been observed to be from the 

 time when the ovum first enters the tubes, we 

 shall be disposed to conclude that fecundation 

 very probably takes place before then, or in the 

 upper part of the tubes. 



In the fourth place, attempts have been 

 made to trace the seminal fluid in animals 

 opened shortly after sexual union. Most 

 authors agree that much of the seminal fluid 



* We do not mean here to state that the parts of 

 the ftEtus have appeared, but only that changes in 

 the germinal membrane preparatory to the forma- 

 tion of (lie fu-tus have taken place. Nothing of 

 this kind has ever heen found in the unimprf^n:!ti-il 

 animal, no appearance of any ovum, which, con* 

 idering how often vesicles are burst without sexual 

 union, u c think must have been the case had the 

 ovum undergone the same changes in the unini- 

 pregnated as in the impregnated animal until its 

 arrival in the uterus. 



frequently flows out of the vagina soon after 

 coition, and Harvey, De Graaf, and Haller 

 were all unable to discover any traces of 

 seminal fluid in the uterus even of various 

 animals killed and opened soon after sexual 

 union. Haller, however, while he states this 

 as the result of his experiments, admits that 

 the means which he possessed of ascertaining 

 the presence or absence of the semen were im- 

 perfect, and he himself believed that fluid to 

 nave entered the uterus. 



Various other physiologists, also, state that 

 they have found seminal fluid in different 

 parts of the female organs. Morgagni and 

 Ruysch had two opportunities of examining 

 the body of the human female very soon after 

 coition, and found, on opening the uterus, a 

 fluid which they regarded as semen. John 

 Hunter states that he observed the same in a 

 bitch, as also did Hausmann. But in all 

 these instances some doubt may be enter- 

 tained regarding the fluid which was considered 

 as semen. 



Prevost and Dumas, trusting to the occur- 

 rence of the seminal animalcule as a certain 

 sign of the presence of seminal fluid, state 

 that they have observed these animalcules, at 

 different periods after coition, both in the 

 uteius and tubes of dogs and rabbits; and it 

 appears to result from the careful series of 

 experiments performed by these physiologists 

 that the longer the time was which had elapsed 

 after coition, the farther the seminal fluid had 

 advanced upwards within the female genital 

 passages. Thus, at twenty-four hours after 

 coition a great quantity of animalcules were 

 found in the cornua of the uterus, but none 

 either in the vagina or farther up the tubes ; 

 at forty-eight hours nearly the same was the 

 case : on the third and fourth days there were 

 many animalcule still in the cornua and some 

 in the tubes, which continued in the dog till 

 the fifth and sixth days ; and upon one occa- 

 sion only they observed a few animalcules 

 near the infundibulum. 



Burdach and others, again, are not inclined 

 to place much reliance on these observations, 

 because animalcule of the nature of Cercarise 

 have been noticed in the genital passages of 

 female animals which had had no connection 

 with the male. 



In the fifth place, experiments on the me- 

 chanical obstruction of the uterus, Fallopian 

 tubes, and vagina, appear of considerable im- 

 portance in reference to this part of our sub- 

 ject. Experiments of this kind were per- 

 formed first by Haighton,* and afterwards by 

 Blundell ; the results of which, making allow- 

 ance for the more accurate knowledge we now 

 possess respecting the indications afforded by 

 the condition of the vesicles and corpora lutea 

 in the ovary, may be stated as follows : 



1st. That when one of the cornua of the 

 uterus or Fallopian tube of the rabbit is divided 

 within a few hours after coition, and oblite- 

 ration of the tube has followed, although 

 corpora lutea are formed in both the ovaries 



Philos. Transact, vol. Ixxxvi. p. 173. 



