340 STUDIES ON PATHOLOGIC OVA. 



cephalus, on the other hand, probably would very seriously affect the further 

 development of the cyema, even if not evident externally. 



It is strange that we know so little regarding the anomalous development 

 of the chorion as a factor in the termination of pregnancy. That the cause for 

 the latter not infrequently may be sought in the ovum or spermatazoon one can 

 scarcely doubt, for otherwise one would have to assume that the human repro- 

 ductive cells are characterized by a unique immunity and perfection. That this 

 is not the case has been abundantly shown for the human spermatazoon, but we 

 are still quite ignorant concerning the occurrence of pathologic unfertilized ova. 

 Jones (1897), however, came to the conclusion that they were common, and 

 Detleftsen (1914) reported that abnormal ovaries commonly occur in guinea-pig 

 hybrids that is, crosses between the domestic and the wild cavy species. Further- 

 more, Huber (1915) found abnormal fertilized ova which disintegrate even before 

 implantation in the rat. 



Crosti (1896) believed that abortion in the first 8 or 10 weeks is always due 

 to defects inherent in the ovum, and Szasz (1903) stated that fetuses from the early 

 months of gestation may show malformations not found in the later months. 

 If this be true, then it demonstrates what one would seem to be able safely to 

 assume, that the existence of some fetal anomalies makes continued development 

 impossible. Such anomalies, hence, never should be met in the newborn, but 

 should be found in the early fetus only. This conclusion of Szasz would also seem 

 to be justified if fetal anomalies were more common in the earlier than in the later 

 months of pregnancy. This was the conclusion reached by Mall (1917), who 

 found that localized anomalies are twelve times as common in abortuses as are 

 monsters among fetuses at term. But since not only acardiac monsters, but also 

 small nodules, such as reported by Slemons (1917 a ) under the caption "Fetus 

 amorphous anideus," may sometimes survive until term, it is difficult to sub- 

 stantiate the assertion of Szasz at present, except perhaps indirectly by the greater 

 infrequency of anomalies at term and by the occurrence of such heretofore unknown 

 specimens as No. 1843 (Meyer, 1919 e ), in which survival was manifestly impossible. 

 Such vesicles as this, wholly devoid of a cyema, apparently never can continue to 

 develop for any length of time, and, as far as I can learn, never have been observed 

 before; for the large hydatiform degenerations, composed of portions of a chorionic 

 vesicle and villi only, really belong in another category. 



No one will doubt that the presence of certain developmental anomalies 

 tends to fetal death and hence also to early abortion, but until more material 

 is available it will be impossible to make reliable statistical deductions and 

 determine the relative frequency with which various anomalies occur in the 

 different months of pregnancy or even at the time of birth. However, there is no 

 doubt that small primary nodular forms, which are true developmental anomalies, 

 such as those shown in figures 205 and 206 (plate 18, Chap. XIII), are far more 

 frequent among young than among older specimens in the Carnegie Collection. 

 This, however, does not wholly confirm the statement of Szasz, though it is in entire 

 accord with Mall's conclusion. If one considers the external form and the structure 



