PLACENTA. 381 



" I perceived likewise, that the red injection of the arte- 

 ries, (which had been first injected) had passed out of the sub- 

 stance of the placenta into some of the veins leading from the 

 placenta to the uterus, mixing itself with the yellow injec- 

 tion ; and that the spongy chorion, called the decidua, by Dr. 

 Hunter, was very vascular, its vessels going to and from the 

 uterus, being filled with the different coloured injections." 



We have quoted the above in full, for the reason that 

 this observation seems to show that the uterine vessels com- 

 municate with great sinuses or lakes of blood in the placenta. 

 This view was at first pretty generally adopted by anatomists ; 

 but some observers subsequently denied this arrangement, 

 supposing that the uterine vessels terminated at the placenta 

 without penetrating this organ. Adopting, however, the 

 Hunterian view of the arrangement of the maternal vessels, 

 Reid showed, by injections of the umbilical vessels, that the 

 foetal tufts of the placenta were supplied with blood from the 

 umbilical arteries, which was returned to the foetus by the 

 umbilical vein. 1 



The important point in the determination of the connec- 

 tion of what may be termed the 'placenta! maternal sinuses 

 with the vessels of the uterus can be settled by injection of 

 the uterine vessels in cases in which the observation can be 

 made while the placenta is still attached to the uterine walls. 

 Dalton, since 1853, has examined the parts in situ in four 

 cases of women who died undelivered at or near the full 

 term of pregnancy, and adopted the ingenious expedient of 

 filling the uterine vessels with air, by which the course of the 

 injection could be directly observed. This operation is per- 

 formed in the following manner : The uterus, with its con- 

 tents, is removed from the body, is carefully opened, and the 

 foetus is taken out, after dividing the umbilical cord. The 

 parts are then placed under water, the end of a blow-pipe is 



1 REID, On the Anatomical Relations of the Blood-vessels of the Mother to those 

 of the Fcetus in the Human Species. Physiological Anatomical and Pathological 

 Researches, Edinburgh, 1848, p. 316, et seq. 



