330 STUDIES ON PATHOLOGIC OVA. 



Nor is the term villous nodules wholly unobjectionable, for they are not, as a 

 rule, composed to any appreciable extent of villi, though a group of 6 or more 

 villi not infrequently pass through or are united by them. But since it seemed 

 the least objectionable term, I have adopted it. 



That these nodules really have the origin attributed to them by Rossi-Doria 

 seems undoubted, although it is not impossible that rarely they may contain 

 some adhesions or inclusions of decidual cells. These would be entirely accidental, 

 however, and would result from portions of the decidua adhering to or being 

 surrounded by the proliferating Langhans cells, and thus becoming included 

 in the nodules. If, as Rossi-Doria stated, and as I believe, they arise from the 

 Langhans layer of the villi, then the fact that they frequently contain masses of 

 syncytium within their interior or at their margins offers no difficulties to those who 

 believe that the syncytium arises from this layer. Nor would it be difficult to 

 explain the presence of included syncytial masses within the nodules upqn the 

 assumption that the syncytial layer has an origin independent of the Langhans 

 layer. But in any case, an origin from either of these layers would imply that they 

 might be expected to be especially numerous in any condition in which unusual 

 activity occurs in these layers. Hydatiform degeneration is such a condition, 

 and that these nodules are especially numerous in many of the specimens of 

 hydatiform degeneration can easily be demonstrated. Whenever the epithelial 

 proliferation is very pronounced, however, it does not manifest itself in the for- 

 mation of nodules, but in the production of irregular trabeculse, garlands and 

 even trellis-works of cell-cords, such as represented in figure 9 (plate 1, Chap. IV). 

 It also is conceivable that these spherules might form during the stage of spon- 

 taneous regression of Iryperactivity of the epithelium or in the earlier stages of 

 hyperactivity; for a more or less spherical nodule manifestly could result only 

 from proliferation in many instead of predominatingly in one or two directions only. 



I have also found these nodules common upon the ends of the villi, as is shown 

 so well to the left in figure 285 and still better in figure 116 (plate 10, Chap. VIII). 

 But, as noticed by previous investigators, and as shown in figures 285 and 286, 

 they are not limited to these locations. I have never found them stalked, but 

 always sessile, and embedded in the stroma of the villi even, as shown in figure 287. 

 Indeed, not infrequently the epithelial proliferation, instead of resulting in an ele- 

 vation upon the surface of the villi, extends largely into the stroma, so that sections 

 of nodules were completely surrounded by it. All manner of transition stages 

 between extravillous and intravillous locations were seen, and more or less hemi- 

 spherical accumulations also were found directly upon the chorionic membrane. 



It is not at all uncommon to find these nodules located nearer the base of a 

 villous tree, as shown in figures 288 and 289. This does not, however, imply that 

 those so located were not apical once, for they may have formed on a short side- 

 branch which they completely surrounded. Not infrequently several villi, even 

 up to half a dozen or more, may be united by and terminate in a single nodule, 

 as shown in figure 291; or they may penetrate it, as represented by Kollman. 

 Not infrequently considerable groups of nodules are found in a single small region, 



