190 PHYSIOLOGY CHAP. 



many, without, however, any proof, that the ovary is usually 

 embraced by the infimdibulum with its numerous fimbriae ; that 

 this immediate contact of the surface of the ovary with the tube 

 is facilitated by the state of turgidity of both organs during and 

 after coitus. There has also been suggested the intervention of 

 the muscular fibres of the extremity of the tube, by which might 

 be carried out active movements directed to secure the ingress of 

 the ovum into the oviduct. These suppositions are all gratuitous, 

 or directly contradicted by observations on animals. It has been 

 demonstrated, however, by Kossman (1903) that the very numerous 

 fimbriae of the infundibulum, with the ciliated epithelium with 

 which their internal surface is provided, act in their entirety as 

 a powerful aspirator, capable of producing a continuous current, 

 directed towards the tubal canal, which sucks up and transports 

 towards the uterus all the corpuscles which happen to be in the 

 liquid expelled from the burst follicle. The ovum, therefore, can 

 be easily aspirated and drawn into the oviduct, whatever the 

 position of the burst follicle on the surface of the ovary or its 

 distance from the tubal canal. 



Arrived in the tube, the ovum proceeds towards the uterus 

 very slowly, either by the direct impulsive action of the cilia of 

 the epithelium which lines the canal, or through the effect of 

 the peristaltic contractions of the muscular wall, contractions 

 analogous to those which take place in the vas deferens of the 

 male during ejaculation of the sperm (Kossmann). The latter 

 mechanism appears more probable, for the oviduct, especially in 

 the isthmus, is somewhat narrow, which accounts for the fact 

 that the ovum may stay several days in the oviduct, and may 

 occasionally become adherent and develop there, if it has been 

 fertilised (tubal pregnancy}. 



Where does the meeting of the spermatozoa with the ovum, 

 which makes possible the fundamental phenomenon of fecundation, 

 occur? In order that fertilisation may take place, it is necessary 

 that the ovum should divest itself of the cells of the cumulus 

 oophorus which surround it when it is expelled from the follicle, 

 and should present its zona pellucida bare, before a covering is 

 formed round it, as happens during its passage through the 

 oviduct. It is therefore very probable that the meeting of the 

 two sexual elements occurs in the abdominal cavity, and precisely 

 in the tract which lies between the burst follicle and the infundi- 

 bulum of the tube (Strassmann). That the sperm can reach the 

 ovary is shown by the old observations of Bischoff (1844), who 

 saw in mammals that, within a short time of copulation, the 

 surface of the ovary was covered with spermatozoa. The cases of 

 ovarian and abdominal pregnancy would be inexplicable without 

 admitting that the meeting of sexual elements and the consequent 

 fertilisation may take place in the abdominal cavity. To-day 



