AND ITS CONNEXION WITH THE UTERUS. 
59 
in the veins by a continuity of canal, whereas in the uterine portion there are 
intermediate cells, into which the arteries terminate, and from which the veins 
begin 
It is a singular fact, that these celebrated anatomists should both have as- 
serted their claims to the merit of what they supposed to be the discovery of 
the true structure of the human placenta, and its connexion with the uterus, 
and that their controversy on this subject should have loosened those bonds of 
affection which had united them together from their earlier years -p. 
Noortwych, Rcederer, and Haller, had previously investigated this sub- 
ject by injecting the blood-vessels of the gravid uterus : their researches how- 
ever did not determine, in a satisfactory manner, that a vascular connexion 
exists between the uterus and cells in the placenta. The opinions of the 
Hunters were generally acquiesced in at the time they were promulgated, 
and their accuracy has not been called in question by any anatomist of repu- 
tation in this country for the last forty years. 
In the communication which I have now the honour of presenting to the 
Royal Society, I propose to describe certain appearances which I have ob- 
served in the examination of six gravid uteri, and many placentae expelled in 
natural labour, which seem to demonstrate that a cellular structure does not 
exist in the placenta, and that there is no connexion between this organ and 
the uterus by great arteries and veins. 
If an incision be made through the parietes of the gravid uterus, where the 
placenta does not adhere, the membrana decidua will be observed lining the 
internal surface, and numerous minute blood-vessels and fibres passing from 
the inner membrane of the uterus to the decidua. At the circumference of 
the placenta, the membrana decidua separates from the chorion and amnion 
to pass between the uterus and placenta, and thus forms a complete mem- 
branous septum, which is interposed betwixt these organs. The chorion and 
amnion cover the foetal surface of the placenta ; and between these two mem- 
branes and the decidua lie the ramifications of the umbilical vein, and arteries 
subdivided to an almost indefinite extent, and connected together by white slen- 
* Anatomical Description of the Gravid Uterus and its Contents, by the late W. Hunter, M.D. 
London, 1794: page 48. 
f Their letters are preserved in the Archives of the Royal Society. 
i 2 
