218 STUDIES ON PATHOLOGIC OVA. 



continuity with the proliferating Langhans layer, and that the syncytial masses 

 were more angular in form, of smaller size, and contained retracted nuclei. The 

 syncytial masses on the hydatiform villus, on the other hand, were said to be more 

 rounded in outline, elongated or polygonal in form, and to possess large nuclei 

 very rich in chromatin. 



Although Durante (1898) represented extremely long syncytial buds, he never- 

 theless found (1909) epithelial proliferation present only where certain vascular 

 changes were present. Winter (1907) stated that the condition of the epithelium 

 varies greatly, and Falgowski (1911) emphasized that he could not demonstrate 

 the presence of an increased epithelial proliferation or of vacuolation of the syncy- 

 tium. Amann (1916) also found that epithelial proliferation may be wholly absent. 



That the degree of epithelial proliferation varies greatly, and necessarily so, 

 not only in the villi of the different vesicles but in those of the same vesicle, is splen- 

 didly illustrated by the villi of No. 7206, shown in figures 107 and 108. In the 

 former epithelial proliferation has not extended beyond that required by the 

 increase in surface due to the increase in caliber of the villi, while in the latter a 

 very long, branching epithelial framework and smaller processes are present. 

 Likewise, in figure 109 (No. 540), the large villi show little epithelial proliferation, 

 while the small villus to the right shows very marked proliferation. Nor are the 

 variations in the degree of epithelial development limited to different "villi of the 

 same specimen, for they may be present even in the same villus. Ballantyne 

 and Young (1913), on the contrary, found epithelial proliferation "so well developed 

 that it suggested that it is an essential process in the formation of the mole." 

 They further likened hydatiform degeneration to edematous growths and empha- 

 sized that both really are epithelial new growths. This opinion is accepted also by 

 de Snoo (1914), who regarded the hydatiform mole as a neoplasm of the trophblast 

 with secondary changes in the stroma. 



There is no agreement at present as to whether the epithelial changes are 

 primary or secondary. As is well known, Marchand (1895), and Miiller, Ercolani, 

 and Langhans long before that, regarded the epithelial changes as primary, but 

 most investigators seem to have come to an opposite conclusion. Some share the 

 opinion of Schroeder that hydatiform degeneration points to a stimulus resulting 

 in hyperplasia of the entire chorionic villus. Nor is there agreement as to what the 

 initial changes are. Durante (1909) regarded the presence of vessels with an imper- 

 fect endothelial lining and with thick infiltrated walls as the initial lesion in hydati- 

 form degeneration. These changes were noted by him, especially in trunk villi, 

 and epithelial proliferation was most evident where the vascular lesions were most 

 pronounced. Durante further stated that the chain form of the hydatids is due to 

 the fact that the vascular lesions occur at intervals along the villus. Unfortunately, 

 the structure of long hydatiform villi does not confirm such an explanation nor 

 Durante's conclusion that the hydatid cavities within the villi result from dilatation 

 of the capillaries. Many investigators report the early disappearance of the blood- 

 vessels, a phenomenon which some regard as secondary and others as primary to 

 the death of the embryo. 



