THE TRANSMIGRATION OF THE OVUM.
The F- all-opian tubes, the excretory ducts of the female sexual glands, consist of the upper portions of the ununited Mfillerian ducts, which embryologically are not in connection with the ovaries; this accounts also for the ex tremely delicate, incomplete and slight connection of the abdominal end of the tube with the ovary. The manner of the transmission of the ovum in the human species is as yet uncertain. A series of hypotheses have been advanced, but only to be relinquished. I will only mention the recent view of Plank, that a union between the tube and ovary is effected by normal adhesions, which permit of the passage of the ovum. Slight pathologie,a1 processes, which appear also to be not infrequent among ani mals, have certainly given rise to this view. And that older view, recently revived by Kehrer, that the ovum is projected with a certain amount of force into the infundibuluni of the tube, has this against it, that the in testinal loops would surely lie in the way.
If we take into consideration the anatomical formation of this division of the genitals, and call to our aid comparative physiology for an explana tion, we find that there can be only two powers capable of bringing about the transmission of the ovum: the erection of tlu3 fimbriated extremity and the ciliary movement of the mucous membrane of the tube. That by a marked distension of tho numerous blood-vessels, resembling spongy or cavernous tissue, of the abdominal portion of the Fallopian tubes, the latter may become erected, and in that way approach the ovary, can be shown experimentally, even though the movements that then appear can by no means be looked upon as satisfactory and efficacious. Still, experi ments upon animals, which were instituted during the period of ovulation, furnish proof of the view that such a movement directed towards the sur face of the ovary does in fact exist, whereby the fimbriaa are placed in ap position to the organ, or glide t,o and fro on it. With these erectile processes, whether occurring naturally or induced artificially, the contrac tion of the muscular tissue, which is quite profuse in this neighborhood, may co-operate, as is emphasized by Rouget. The force with which this erection is caused, must, however, be a tolerably powerful one, since it must overcome the resistance of the overlying intestines.
The second power lies in the ciliary cells, which line the ampulla of the tube, and since the ciliary movement of the ciliary processes is directed from the abdominal cavity toward the uterine, the mucous membrane is without question in a condition to carry the extruded and received ovum to the narrow part of the tube. The great capability of the ciliary move
ment principally, as well as the fact that among the lower animals an ovum lying free in the abdominal cavity is brought from a considerable dis tance to the tube by this force alone, speaks positively for the probability that this arrangement plays an important, if not the most important part also in the human species. For it is not improbable that the ciliary movement manifests itself beyond the ampulla, in that it brings about that constantly occurring flow of the normal fluid on the surface of the peritoneum, toward the ampulla of the tube, and thereby also carries the ovum, extruded from the ovary and taken up by the flowing fluid, into the excretory duct of the ovary. By the incomplete union of the ovary and tube, and, as it appears, by the insufficient capability of move ment of the fimbrim, there cannot be ascribed to the erection of the ab dominal tubal end, originated and maintained by the catamenial congestion of the genitals, the power of grasping the extruding ovum directly, but only the power of drawing near the surface of the ovary. The principal activity would be ascribed to the ciliary movement, which not only would carry the ovum through the free peritoneal cavity, but also through the anipulla to the narrow part of the tube. The movements of the fimbri ated extremities could only be looked upon as an auxiliary action.
The further advancement of the ovum through the narrow part of the tube is brought about by the force of the ciliary movement; peristaltic action of the circular muscular tissue of the tube probably aids in the ad vancement of the ovum. The passage through the tube occupies several days, according to investigations among the higher classes of animals. This period is not a fixed one in the human species. Only in the event of pregnancy does the ovum remain in the uterus; if this does not occur, the orum diee and is thrown off. The process repeats itself then in the mme way, after the lapse of the time before mentioned.
If the ovum is impregnated, the maturing and detachment of new ova ceases; very probably also during the retrogressive metamorphosis of the genitals (puerperium). Ovulation appears to be arrested also dur ing lactation, but still only at the beginning of this epoch, for conception during. protracted suckling is certainly not infrequent.