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



into which the trophoblast extends, and in turn the blood reaches to the chorionic 

 membrane, filling entirely the small spaces between the villi, which are just begin- 

 ning. We have here a true intervillous hemorrhage which many often speak of as 

 a primitive intervillous circulation. On the other hand, we have two other young 

 human ova in which there is practically no blood in the intervillous spaces. The 

 one recorded by Jung is from uterine scrapings. The specimen is somewhat older 

 than that of Peters. It was removed with a large mass of uterine mucous membrane 

 attached, so if the intervillous spaces had been normally filled with blood, it is not 

 improbable that it would have run, leaving the empty spaces filled with clear fluid. 



The other case is that of Strahl and Beneke, whose specimen was also obtained 

 from uterine scrapings. In this case a number of large vessels and sinuses in the 

 neighborhood of the ovum are filled with blood, but most of the intervillous spaces 

 are empty. 



A similar specimen found in situ by Frassi establishes the theory that the 

 freshly implanted ovum is not always embedded in a mass of blood. In the Frassi 

 specimen the intervillous spaces were found empty, but in direct contact with the 

 uterine veins. Frassi, however, concludes that this condition does not speak 

 against an intervillous circulation, but rather in its favor; and this opinion is also 

 entertained by Grosser. 



In our own collection we have a specimen about the size of Herzog's or Peters's 

 with practically the same intervillous hemorrhage. The specimen (No. 763) is 

 somewhat more advanced than either of the two others; it was obtained from 

 uterine scrapings and appears to be normal in every respect. However, in later 

 stages it does not appear as though the hemorrhage is as pronounced as in some of 

 the earlier specimens studied. In fact, this point has been commented upon fre- 

 quently, and it is usually stated that the absence of blood between the villi is due to 

 contraction of the uterus when the entire organ is removed at operation or to rup- 

 tured intervillous spaces when the specimen is obtained from the abortion. It has 

 always seemed to me probable that in the latter instance the rupture has allowed the 

 blood to enter instead of escape and that in the former it is very remarkable that 

 the contraction of the uterus should have pressed out the blood corpuscles and 

 allowed the blood plasma to remain. At any rate, in older specimens which have 

 been examined in situ it is difficult to show that an intervillous circulation exists. 

 Some embryologists have overcome this possibility by stating that intervillous cir- 

 culation is a condition peculiar to the second half of pregnancy. After examining 

 several well-preserved specimens in situ, I am convinced that this question is by 

 no means settled, and must still be regarded as open. 



At this point the findings of two excellent specimens may be cited. One is 

 from an ovum and uterus containing a normal embryo 26 mm. long (No. 782) and 

 the other is from a specimen containing an embryo 4 mm. long (No. 836). 



In the first specimen the entire uterus was hardened in strong formalin and 

 was carefully cut into slabs, so that the attachment of the chorion to the uterus 

 could be studied to advantage. There was practically no blood between the villi 

 in this specimen and the tips of the villi were firmly attached to the uterine wall. 



