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



between the villi, which ultimately detaches the chorion from the tube wall and 

 causes the death of the embryo. This condition, which should be viewed as a true 

 intervillous circulation, seems to prove fatal for the embryo. In the tube such a 

 condition must end in the destruction of the ovum and in the uterus in an abortion. 

 Unless the activity of the trophoblast is sufficiently pronounced to destroy the 

 masses of blood which become lodged between the villi and at the same time prevent 

 further hemorrhage into these spaces we can hardly expect a normal implantation. 

 From all appearances the development of the chorion of No. 612 is such that we 

 could have expected the further development of a normal embryo in case the tube 

 had not been removed by the surgeon. There is a beautiful, active, vacuolated 

 syncytium which forms a pretty complete wall around the intervillous clot. This 

 wall is sufficiently solid to prevent any great amount of new blood from entering 

 these spaces. The trophoblast is growing in among the muscles of the tube wall and 

 it is also to be seen in many of its blood-vessels. 



NORMAL EMBRYOS OVER 9 MM. LONG. 



A more advanced stage is seen in a similar specimen (No. 109) which contains 

 an embryo 10.5 mm. long. This also shows a considerable amount of blood between 

 the villi, but most of it seems to be fresh. A portion of the clot is stratified, but the 

 rest does not show any marked signs of coagulation. Part of the stratified clot has 

 within it a group of leucocytes. The chorion appears to be normal, and where it 

 comes in contact with the tube wall its trophoblast is extremely active. It forms 

 a wall which prevents further hemorrhage from the vessels of the tube into the inter- 

 villous spaces. Various stages of this process are shown in the figures of this speci- 

 men. In plate 1, figure 2, the trophoblast within the sinuses is shown. Most of the 

 endothelial lining of the veins has been destroyed, but part still remains, as shown 

 in the figure. An earlier stage of this process of destruction of the wall of the blood 

 vessels is shown in plate 1, figure 1. Here are found all stages of trophoblastic 

 development, from the tips of the villi to the free cells within the blood vessels. A 

 somewhat more advanced stage is shown in plate 1, figure 3. The wall of the venous 

 sinus has been completely destroyed and in its place are strands of trophoblast. 

 Between the lumen and the villi is a pronounced vacuolated syncytium partly filled 

 with blood. This specimen illustrates beautifully the dam thrown up by the tropho- 

 blast to prevent hemorrhage from the open veins. The blood between the villi is 

 well encircled with trophoblastic cells; at some points the leucocytes have invaded 

 it. A large clot, which is about 15 mm. long and 2 to 5 mm. thick, separates in part 

 the chorion and the villi from the tube wall. On the chorionic side it is covered 

 with an incomplete layer of trophoblastic cells, as shown in plate 4, figure 3. 

 These seem to be invading the blood clot. Individual cells are often found far from 

 their main strand, as shown in this figure. Undoubtedly we have here a clot of 

 blood which the trophoblast is attempting to destroy. There is no indication of 

 fresh hemorrhages in any of the sections. The trophoblast is extensive and vacuo- 

 lated, forming a wall which protects nearly all of the intervillous spaces. 



