72 STUDIES ON PATHOLOGIC OVA. 



so that the whole amniotic cavity could be carefully inspected without opening the 

 vesicle. In view of these facts, no other explanation for the abnormal proportions 

 between the two vesicles seems possible than the assumption of the growth of the 

 chorionic vesicle after the death of the embryo and amnion. It also is possible 

 that both embryo and amnion may have been retarded and the chorion accelerated 

 in its growth, but the great disproportion between the embryo and amnion makes 

 even this assumption, as sole cause of the disproportion, rather improbable. 



It is not at all surprising that the idea that the fetal membranes can continue 

 to grow independently after the death of the embryo was once quite generally 

 held, for the disproportion between the size of the membranes and that of the 

 contained embryo is often very striking. Seiler (1832) also stated that the embryos 

 in aborted ova usually are too small. In most of the cases the disproportions may 

 be due largely or wholly to the existence of a genuine or of a pseudohydramnios, 

 but in others this apparently is not the case. The fact that the yolk-sac, too, 

 may be entirely too large in comparison with the embryonic disk also seems to 

 suggest that it, too, is somewhat independent in its development, and since the 

 amnion usually is non-vascular, it is not at all unlikely that its growth is not 

 inhibited immediately after the death of the embryo. Yet such growth probably 

 could not be long continued before the amnion is fused with the chorion, for with 

 death of the embryo and consequent change in composition of the amniotic fluid 

 further growth probably would become difficult. But after fusion of the amnion 

 with the chorion, the former obtains a more or less independent source of nutrition 

 and consequently is affected less by a change in composition of the amniotic fluid. 

 That the chorion may remain well implanted some time after the death of the 

 embryo can not be doubted, and although cessation of the fetal circulation probably 

 would seriously interfere with its proper nutrition, this interference would not neces- 

 sarily prevent some growth on its part. This would be true especially of early con- 

 ceptuses in which the circulation had not as yet been long established. However, 

 that the chorion can undergo considerable independent development is open to 

 grave doubts, and it may be recalled that it used to be held quite generally that the 

 placenta also grew after the death of the fetus. Schickele (1907) also doubted 

 the occurrence of growth of the chorion after the death of the embryo. 



Most of the specimens in this, as those in the two previous groups, are small . 

 This becomes evident especially if it is recalled that, as stated in the previous 

 chapter, the main bulk of these abortuses often is due to blood-clot, decidua, and 

 even to the products of inflammation. This is splendidly illustrated by No. 77, 

 which measured 70 by 40 by 30 mm., although the contained chorionic vesicle 

 was only about 22 mm. large. Similar instances are Nos. 408 and 564. 



The same pathologic conditions which were present in group 2 recur here 

 with somewhat the same frequency. In the case of No. 813 the chorionic cavity, 

 which measured 70 by 25 mm., had an extremely thickened wall, which, in con- 

 nection with other changes present, suggested changes produced by lues, although 

 the history carried the comment "No venereal disease." This specimen contains 



