64 ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 



In general, then, it is the poles of the body that suffer most, the head being 

 deformed in 75, the legs in 50, the arms in 40, and the trunk in 4 per cent of the 

 cases. But while it is clear that a good share of the difficulty is due to ordinary 

 mechanical causes, in the 12 cases that were markedly monstrous these could not 

 be the sole factor; for them we must hold the hemorrhagic placenta responsible, a 

 growth that could be included under what I have termed faulty implantation. 

 Therefore, 14 per cent of Von Winckel's 87 tubal cases which were normal in early 

 pregnancy become monstrous, while in uterine pregnancies the percentage is below 1. 



PATHOLOGICAL OVA. 



Pathological ova without embryos are very frequently encountered. In our 

 selected cases 59 per cent fall under this heading, while in specimens obtained from 

 the uterus there are only 2.7 per cent. Moreover, as Werth also admits, in both 

 sets the figures are probably much too small, as no doubt many of the earlier speci- 

 mens are lost or overlooked. We have no good data regarding the number of ova 

 which disintegrate early, but the study of comparative embryology warrants the 

 conclusion that many young ova degenerate and disintegrate. I am informed by 

 Doctor Huber, who has studied with great care much material from rats, that some 

 of the fertilized ova break down before implantation or what amounts to implanta- 

 tion. The same seems to be true regarding the pig. We usually find more corpora 

 lutea in the ovaries than embryos in the uterus, indicating that all of the ova do 

 not produce normal embryos. 



Table 13, which includes all of the pathological ova studied, shows that most 

 of them are less than 10 mm. in diameter. Many of them are small because they 

 are collapsed. At one time they were larger, but as a result of excessive hemorrhage 

 they became detached, and the collapsed ovum indicates that it is degenerating. 

 Verj r few of them are in a process of abortion and none of them have ruptured 

 through the tube wall. The ova are simply being disintegrated. This is indicated 

 by the pathological condition of the magma, which is densely reticular and often 

 very granular. The wall of the chorion is degenerating and the line of demarcation 

 between it and the ccelom is often obscure. Strands of cells extend from the 

 chorionic wall into the ccelom, and the main wall of the chorion is often ruptured. 

 The villi usually show a variety of degenerative changes of which the most common 

 is fibrous, but often mucoid. The trophoblast is usually scanty or necrotic, with 

 disintegration of the nuclei, forming nuclear dust. When this is liberated, it is 

 scattered through the specimen. The dead villi are soon invaded by the leucocytes 

 and also by adjacent trophoblast which feeds not only upon them but also upon 

 necrotic masses of trophoblast. As the ovum collapses it also begins to break up. 

 The villi are detached and scattered in the blood clot. The isolated villi may con- 

 tinue to grow in case they are capped by active trophoblast, which continues to 

 tap fresh vessels. As the blood clot becomes larger the single villi are separated 

 more and more, ultimately undergoing complete degeneration. In a few instances 

 the whole ovum breaks into pieces. It first becomes hourglass in shape, the two 

 parts then separate, and in one case (No. 874), one part is aborting, whereas the 

 other part is near the uterus, where it is still growing actively. Finally, the villi 



