324 STUDIES ON PATHOLOGIC OVA. 



the presence of many exceedingly fine branches and perhaps even of early villi, almost 

 alfof which, nevertheless, are highly vascular. Those in figure 276 are practically 

 unmacerated, for they came from a fresh, normal abortus, and in spite of their 

 extreme delicacy and curliness, I know of no reason to regard them as pathologic. 

 That shown in figure 277 came from a retained infected conceptus, but to 

 extent its form can be attributed to these facts is difficult to decide. It scarcely 

 seems to me that such a marked diversity in form could exist in strictly normal villi, 

 and it is possible that local conditions may to a large extent influence, even if 

 they do not determine, the type of a particular villus. 



I regret that it has not been possible to compare villi from placentae of the 

 same age, but from different pregnancies, in the same women, in order to determine 

 the possible occurrence of variations in the type of villi in succeeding pregnancies. 

 There seems to be no doubt that the diversity in form of villi increases rather than 

 decreases with advancing age of the conceptus, and that the differentiation -extends 

 even to the last months of pregnancy. At this time, however, the more prevailing 

 type of normal villus appears to be such as that from the thirty-first week, shown 

 in figure 279. 



Normal villi apparently vary greatly, not only in length and caliber, but also 

 in complexity and manner of branching, and in the appearance of their surfaces, 

 which change from smooth to extremely knobbed. It is not uncommon to find 

 that exclusion of the villi reduces the measurement of a chorionic vesicle from one- 

 third to one-half. This is illustrated by the specimens in figures 231 (plate 19, 

 Chap. XIII) and 253, both of which are relatively small vesicles. Nor are these 

 long villi always slender and unbranched, for frequently, as illustrated in figure 

 281, in which a more branched, bushy villus from a vesicle 70 by 50 by 40 mm. is 

 represented, they are decidedly umbelliferous. However, as is usually the case, 

 the villi of this specimen were somewhat unequally developed. 



Extreme grades of fibrosis, as represented in figure 283 (plate 24, Chap. XVI), 

 with vessels in varying degrees of disappearance, have been found to occur in 

 cases of long retention in lues and also under conditions of infection. These 

 particular villi were taken from a vesicle measuring only 55 by 35 by 20 mm. 

 Rather unusually formed, clubbed, decidedly macerated villi from an ovarian 

 pregnancy are shown in figure 168 (plate 16, Chap. XI). Anomalous development 

 of villi seems to be more common in tubal, and perhaps also in ovarian, than in 

 uterine pregnancy. In tubal specimens the villi not infrequently are but sparsely 

 developed and bare areas seem to be much more frequent. Moreover, the chori- 

 onic vesicles are often too small in proportion to the contained fetus. This is 

 illustrated well by No. 1151, shown in figure 280. To what extent this dispro- 

 portion is the result of reduction in the size of the vesicles after death of the fetus 

 or to retardation in growth because of an abnormal location, or to both, I am 

 unable to say. Some of the villi of this small vesicle also show hydatiform 

 degeneration, while others merely are macerated, as shown in figure 282. 



Careful examination of young chorionic vesicles has failed to reveal villi which 

 are purely epithelial or ectodermic, nor have I seen any formed by the extension 



