Accessary tubes have been found by Rokitansky, and are worthy of mention. An ovum might get iito the accessary tube, be arrested, and develop there.
Or the entrance of the ovum into the uterine cavity may be impeded. As in Beck's and in Leopold's cases, there may be small polypi in the uterine end of the tube, or fibromata so situated in the uterine substance as to compress the interstitial portion of the tube.
Finally, injuries might have occurred leading to a communication between the vagina or uterus and the abdominal cavity. In this class belong Schroder's two cases. One has been observed by Lecluyse, in which a women had formerly had Caesarean section done on account of pelvic contraction, and who died from the laparotomy done for the subse quent abdominal pregnancy. An opening 1.6 inches long had remained in the Caesarean incision, through which the uterine and abdominal cavities communicated. Kober16 saw a case in a woman whose uterus he had extirpated for a fibroid tumor. She conceived through a fistula left in the scar of the cervix, and died of the pregnancy that resulted. Simi larly, a pregnancy may occur when an inverted uterus has been ablated. We have ourselves observed four weeks after amputation with the red-hot wire the abdominal cavity remaining open; and since the tubes lie in the scar, it is quite possible that one or other may remain patent, and an ovum be fructified, without the uterus, in the remaining portion of the tube, or in its neighborhood. And we may mention W. A. Freund's idea that a disturbance during a fruitful cohabitation might cause an extra-uterine pregnancy.
We must now mention that remarkable process which Bischoff first recognized in the bicornate uteri of certain mammals, and called emigra tion of the ovum, since it may lead to extra-uterine pregnancy. Eschricht, the Copenhagen anatomist, however, as long ago as 1832 noticed that sometimes he found the corpus luteum in the human female upon the sidle opposite to the foetal sac (Kussmaul). Since that time several observers have seen it, and Kussmaul begins the introduction to his above-mentioned monograph in these words: " On December 14, 1857, I made the post-mortem examination of a young woman who had died suddenly from hemorrhage in consequence of the bursting of the sac of a tubal pregnancy. The relations of the corpus luteum were very remark able. The conclusion seemed inevitable that the ovum which had devel oped in the left oviduct had come from the right ovary." Thus we have
anatomical proof of a hitherto unknown origin of tubal pregnancy, and some light is cast upon the subject of the movements of the ovum.
It is clear from Kussmaul's thorough exposition of the subject that all ova originating from the ovary of one side may become imbedded in the opposite half of a simple uterine cavity; and further that an ovum may become implanted in a tube or in an atrophied cornu upon the opposite side, and may develop there. The ovum is supposed sometimes to take the route through the abdominal cavity, extra-uterine migration, and sometimes to pass through the uterus, intrauterine migration. Observa tions of this kind from reliable sources become so numerous that C. Mayerhofer, in an essay " on the corpus luteum and the migration of the ovum " could collect seventeen cases of this kind.
In most of these cases the oviduct or a rudimentary horn of the uterus and one side contained the ovum, while the true corpus luteum was upon the ovary of the other side. If, as most believe, the true corpus luteum is always the point of origin of a fructified ovum, it is impossible to explain these cases upon any other supposition than that of migration.
But Mayrhofer objects entirely to the generally accepted theory as to the relations of the true corpus luteum to the ovary, and does not believe in the migration of the ovum. He does indeed admit that the true corpus luteum differs from the false corpus luteum, inasmuch as the former undergoes a much greater development, and becomes vascularized, while the latter does not. But lie claims that there are exceptions, and that even in virgins we occasionally find corpora lutea which have all the char acteiistics of the true yellow body. Thus Mayrhofer claims that we can not always distinguish the true from the false copora, and both Luschka and Bischoff hold that the character of the corpus luteum will not enable us to decide in doubtful cases. Mayrhofer then goes further, and denies the persistence of the corpus luteum through pregnancy, basing his opin ion upon cases which died during pregnancy and shortly after delivery, and in which no corpus luteum was found, and in still greater degree upon those in whom fresh false corpora lutea were found post mortem at various stages of pregnancy. Thus lie comes to the following conclusion: That the corpus luteum verum does not mark the point of origin of the impregnated ovum, but that it is formed during pregnancy, probably every four weeks.