60 STUDIES ON PATHOLOGIC OVA. 



GROUP 2. CHORION WITHOUT AMNION OR CYEMA. 

 A. UTERINE. 



The absence of the amnion in these specimens seems to be the result of destruc- 

 tion by lysis. However, absence of it in young specimens also might be due to 

 failure of formation. The latter was the opinion of Giacomini (1888), who never- 

 theless believed that deformities of the amnion are rare. The only specimens in 

 which the absence of the amnion could be ascribed to failure of development is 

 No. 1843, donated to Stanford University by Dr. Falk, of Modesto, California. 

 This is a very young specimen, however, and it is not impossible that a small 

 cavity found in it represents the early amniotic cavity, as suggested by Meyer 

 (191 9e). Moreover, it may be doubted whether the human embryonic disk 

 could develop far if formation of the amnion were inhibited. It is true that Panum 

 (1860) and Dareste (1883) both reported cases of absence of the amnion in the 

 chick and that Dareste emphasized that all the cephalic or the caudal portions 

 may be absent. But since it is possible that the process of formation of the amnion 

 is a totally different one in man, the direct application of these observations upon 

 the chick to man is open to question. Panum and Dareste both believed that the 

 anomalies of the amnion, observed by them in the chick, were secondary and the 

 opinion of Giacomini was based largely upon the failure to secure absorption of 

 the amnion experimentally in rabbits. 



Specimens of human abortuses in which the amnion has undergone partial 

 destruction are very common. Moreover, all degrees of destruction are represented 

 in these cases, and since the cyema, too, is usually lacking, the assumption that 

 absence of the amnion is due to failure of formation naturally would necessitate a 

 similar conclusion regarding the embryo. This would leave one in the position 

 of assuming that a chorionic vesicle which never had contained an embryo or 

 amnion nevertheless might develop independently and attain some size. 



Since the absence of the cyema in some of these vesicles is undoubtedly due 

 to the mechanical injury incident to interference with a purely normal gestation, 

 it follows that some of them were unquestionably normally developed chorionic 

 vesicles and hence do not belong in the pathologic division. The difficulty lies in 

 identifying them. Nevertheless, the structural characteristics of some are sug- 

 gestive, even if not wholly unequivocal. In one instance, for example, in which a 

 small nodule was seen upon opening an apparently intact ovum, this nodule was 

 found to be composed of fragments of villi which could have been introduced into 

 the chorionic vesicle only at the time of interference, or accidentally when it was 

 opened in the laboratory. In another instance the chorionic vesicle contained 

 foreign material when opened. Besides, the splendid preservation of the tissues 

 of some specimens also shows that they were obtained in a practically normal, 

 fresh, and unmacerated condition, which rarely is the case in any but instances of 

 induced abortions, whether they be therapeutic, accidental, or criminal. 



As already indicated, there is no hard and fast line of demarcation between 

 the first three and later groups of the pathologic division. Indeed, it is not always 



