FUNCTIONS OF THE FALLOPIAN TUBE.
It has long been determined, with as much precision as the nature of the subject appar ently admits, that the Fallopian tube performs the double office of receiving the ova from the ovary, and conve3ing them into the uterus, and of receiving the spermatic fluid from the uterus and conveying it in the direction of the ovary : the tube itself being, if not con stantly, at least generally, the seat of im pregnation - or, in other words, the precise spot in w filch the material contact of the male and female generative elements takes place.
These conclusions regarding the offices of the oviduct, are deducible from various ob servations and experiments, both of a positive and negative kind, made upon mammalian animals, and the close correspondence which has been observed betw een these and similar observations, so far as they can be made upon the human female, leads also to the conclusion that there is little or no material difference between the mode in which these offices are performed in man and in the mammalia generally.
With regard to the demonstrative evidence furnished by experiments and observations upon animals, as well as by observations upon the human subject, relative to the pre cise offices of the oviduct in the conve3ance of the ova from the ovary, the following points may be considered as established.
The infundibular orifice of the Fallopian tube, together with the fimbrix by which its margin is fringed, at the time of the dis charge of ova, becomes expanded over a cer tain portion of the ovary, the extent of the surface covered varying according to the form and proportions of the infundibulum relatively to the size of the ovary-.
In some mammalia, the cat for example, the infundibulum is sufficiently large to en compass the entire ovary, so that an ovum escaping from any portion of its surface would fall within the receptacle thus provided for it, and be conveyed to the orifice of the tube, and thence into its canal. But in many animals of this class, as well as in man, the size of the infundibulum does not suffice to cover more than a portion of the ovary at any one time, half or a third it may be of the entire surface of the gland; so that in all these cases a selection must be made of the exact spot from which the discharge of an ovum is about to take place, or else the ovum would be lost, by falling into the cavity of the abdomen. That this occasionally hap
pens is rendered evident by those cases in which the infundibulum is glued as it were to a portion of the ovary by morbid adhesion. But while the extremity of the oviduct is thus immoveably fixed, the process of ovula tion still goes on from all parts of the ova rian surface indifferently, so that those ova only which rnight happen to be discharged from the particular spot to which the tube is affixed, would by any possibility enter its mouth, and all the rest would be lost. I have already adverted at p. 560. to such an example, and of this case a drawing is here subjoined. In this instance, three ripe Graafian vesicles had burst on one side of the same ovary, and had discharged their ova, while the mouth of the corresponding oviduct was inseparably united by morbid adhesions to the outer extremity of the gland, and was thus effectually prevented from re ceiving any ova except such as might be dis charged from the spot to which the tube was attached.
By what power the mouth of the tube is directed to the particular portion of the ovary from which an ovum is about to be discharged remains entirely unknown, as, indeed, does also, to a certain extent, the precise nature of the mechanism effecting this movement. The part termed the tubo-ovarian ligament (fig-. 404. d) will at all times serve to keep the infundibulum in contiguity with the ovary, but by what agency the orifice of the tube is drawn towards, and its fimbrim become ex panded upon, the ovary, cannot be very satis factorily explained. These movements can only be referred to the contraction of the low form of fibre of which this part has been shown to be chiefly composed ; and although it is certain that in a great many of the in vertebrata, a similar form of contractile fibre constitutes the sole agency by which their active and sometimes very rapid movements are effected, yet this is not commonly found to be associated with any' considerable degree of' movement in the higher animals.