48 ON THE FATE OF THE HUMAN EMBRYO IN TUBAL PREGNANCY. 



reaching to the periphery of the clot, where they come in contact with fresh blood. 

 Here the trophoblast is active, but there is no ovum to nourish. It appears as if 

 the independent villi possess a considerable power to grow even after they are 

 separated from the ovum. Several specimens, to be described presently, will bring 

 out this point. 



I have separated the last 3 specimens from the rest for the reason that in these 

 cases it is practically impossible to eliminate implantation within the tube wall. In 

 the small specimens it seems quite clear that at most the ovum attaches itself only 

 to the folds of the tube and never becomes well implanted within the muscular wall. 

 As soon as hemorrhage starts up it is naturally detached and encircled by the clot, 

 but in the last 3 specimens it is not clear whether the ovum had only attached 

 itself to the tube wall or had actually become implanted within it. This point can 

 not be determined definitely by the technical methods I have employed. Serial 

 sections are here required. For the present this question remains open. 



Other specimens. In cases in which the ovum remains attached to the side of the 

 tube wall for some time, it is quite clear that the method of its degeneration would 

 differ from that which occurs when the ovum is entirely detached and free in the tube 

 lumen. It certainly seems probable that the ovum receives its nutrition best in 

 case it comes in contact both with the tube wall and with fresh blood. It appears as 

 though both these, elements are required to produce the most perfect pabulum, so 

 that the ovum free in the tube lumen must feed upon maternal blood, while that 

 still attached to its wall receives its nutrition also from the maternal tissues. 



An interesting specimen in this connection is No. 415. It came from an opera- 

 tion which took place 6 weeks after the last menstrual period. The tube was 

 hardened in Mo, and then cut into blocks and the region in which the villi were 

 seen was cut in serial sections. In these was found a small clump of villi attached 

 to the folds in the tube and undergoing mucoid degeneration. At one point there 

 was a single villus within the tissues of the fold encircled by an extensive tropho- 

 blast which radiated in all directions. Here, then, we have a small mass of necrotic 

 villi and a single one which is active. 



A more advanced stage is shown in No. 773. A single fold of the tube has the 

 ovum implanted within it. This fold is distended and looks much like a cherry 

 about 8 mm. in diameter, hanging into the tube lumen, which is about 18 mm. in 

 diameter. Within the center of this nodule are a few villi covered with a certain 

 amount of trophoblast and encircled by fresh blood. From this central mass the 

 blood forms layers which are more successfully organized as the wall of the fold is 

 reached. The principal mass of blood within the tube lumen is of uniform con- 

 sistency, but contains no remnants of the ovum. It appears that this ovum had 

 attached itself within the tissue of the folds and there gradually undergone degen- 

 eration. A similar condition is seen in specimen No. 772. In this trophoblast and 

 villi are more active and some necrotic villi are scattered through the blood clot 

 within the lumen of the tube. 



A far more active picture is supplied by No. 720. Here the trophoblast is 

 attached around for nearly two-thirds of the circumference of the tube. In all 



