HYDATIFORM DEGENERATION IN UTERINE PREGNANCY. 217 



men of hydatiform mole can be recognized by examination with the binocular 

 alone necessarily will depend also upon the condition of the specimen. If the villi 

 are matted, glued, or macerated, not only the early hydatiform changes, but even 

 fairly advanced ones, are often masked so completely that recognition is difficult 

 or impossible without histologic examination. 



In many early specimens the diagnosis could be made at sight from a histologic 

 preparation under low magnification, even when it was impossible to make a 

 diagnosis by examination with the binocular microscope alone. The field of sec- 

 tions of the villi also looks more scattered and the caliber of the villi shows greater 

 variations. What further makes this possible is not, as has been generally assumed 

 since Marchand's epochal work on chorio-epithelioma, the appearance of the 

 syncytium or that of the Langhans layer or of the trophoblast, but the changes in 

 the stroma, which precede those in the epithelium. The evidence in regard to 

 this matter is overwhelming, and in the early stages, when the stroma already has 

 been altered, it often is impossible to tell whether the epithelial development is 

 normally or abnormally active. Moreover, in spite of Marchand's conclusion, 

 extremely large hydatid vesicles often have but a single smooth layer of epithelium. 

 This has been asserted repeatedly by other investigators also. The two layers of 

 epithelium are not by any means always present, and, while there is no agreement 

 in the matter, the opinion nevertheless seems to be that the grade of epithelial pro- 

 liferation can not be used as a criterion for the determination of the presence of 

 hydatiform degeneration. 



Langhans (1902) also stated that Marchand overemphasized the presence of 

 epithelial proliferation, and rightly declared that all sorts of gradations occur 

 between normal and hydatiform villi. Indeed, unless hydatiform villi invariably 

 arise as such when the earliest villi appear, or arise de novo later, all gradations 

 necessarily must exist between normal and hydatiform villi, thus contradicting 

 Marchand's conclusion. 



Menu said that the presence of marked epithelial proliferation was emphasized 

 early by Miiller (1847), Ercolani (1876), Franque (1896), and Owry (1897), and 

 according to Pazzi (1908 b ), Ercolani, and even Polano, denied the existence of 

 connective tissue in the hydatiform mole. The same thing was asserted by 

 Sfameni (1905), who claimed to have found further evidence of the exclusively 

 epithelial nature of the hydatiform mole. According to Sfameni, the hydat- 

 iform mole does not result from a modification of existing chorionic villi, but 

 from an entirely new growth which is wholly epithelial in character! But this 

 opinion, which was accepted also by Niosi (1905), seems to exist among Italian 

 writers only. According to Acconci (1914 a ), marked proliferation of the epithelium 

 occurs also in toxemia of pregnancy and in nephritis. A number of investigators 

 have found it common also in long retention. 



I am unable to confirm the observation of Nattan-Larrier and Brindeau (1908) 

 that the syncytium of hydatiform villi breaks up into individual portions which 

 do not undergo degenerative changes, but penetrate deeper into the decidua. 

 These investigators thought that in normal villi the plasmodium always keeps its 



