HYDATIFORM DEGENERATION IN UTERINE PREGNANCY. 223 



moles was noted by Otto, Marchand (1898), Essen-Moller, and many others. 

 Their occurrence in normal and pathological chorionic vesicles and their significance 

 are considered in Chapter XV. No matter what the condition of the epithelium 

 (or, more specifically, the Langhans layer), the syncytium, and trophoblast may 

 be, the above-noted changes in the stroma always are quite typical. They are 

 not the only changes noted, however, and may differ somewhat as to the time of 

 their advent. 



Not infrequently, changes quite comparable to those in the villi occur also in 

 the stroma of the chorionic membrane itself, a fact which has not heretofore been 

 emphasized. It, too, frequently is decidedly glassy; liquefaction may occur 

 here and there and may become complete in the course of time. Hofbauer cells 

 also are not uncommonly present. Among the changes noted in this membrane, the 

 disappearance of the vessels is the most common and constant, although epithelial 

 proliferation is not rare, as already stated. Moreover, when (as in one of Storch's 

 cases) a hydatiform villus is 15 cm. long, one scarcely can doubt that the stroma 

 also must have proliferated not merely degenerated. Some of the strings of hydatid 

 cysts in a specimen in the Carnegie Collection have a length of 10 to 12 cm., 

 and in these cases also one can hardly assume that this increased length of the 

 villi was unaccompanied by proliferation of the stroma. From these things alone 

 it follows that the stroma can not remain passive always, although Gromadzki 

 (1913) concluded that it never proliferates. Vecchi (1906), however, reported an 

 increase in the stroma of the villi, and it will be recalled that Marchand also 

 implied the presence of proliferative changes in the .connective tissue when he 

 wrote that they depend upon those in the epithelium. 



I have never been able to find mitotic figures, a fact which may be accounted 

 for, however, by the presence of degenerative changes due to intrauterine separa- 

 tion and retention of most specimens. Indeed, the failure to find mitoses speaks 

 against proliferation in the stroma no more than in case of the epithelium, in which 

 the presence of karyokinetic figures has been reported by a few investigators only. 

 Yet pronounced proliferation of the epithelium is often present. The failure to 

 find mitotic figures very likely is due to the condition of the material. 



Careful scrutiny of a large series of specimens has revealed the fact that the 

 disappearance of the vessels in the villi, in the chorionic membrane, and also in the 

 umbilical cord is centripetal as a rule. However, in many specimens the vessels 

 not only may be present in the chorionic membrane, although absent in the villi, 

 but may be very numerous and even engorged with blood. It is difficult to say 

 to what extent the engorged condition of these vessels and of those in the body of 

 the abnormal embryos sometimes contained in these hydatiform moles is due to 

 the propulsion of the contained embryonic blood before the advancing vascular 

 constriction and degeneration, but I am inclined to believe that the centripetal 

 movement of the process is not a negligible factor in this matter. 



Although only a few instances of the birth of a living fetus or of a fetus which 

 has reached the later months of pregnancy are recorded in the literature, it is now 

 quite generally recognized that the fetus, though dead and too small for its men- 



