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III. On the Structure of the Human Placenta , and its Connexion with the 
Uterus. By Robert Lee, 31. D. F.R.S. fyc. Physician to the British Lying- 
in-Hospital. 
Read November 17, 1831. 
In the year 1780 Mr. John Hunter presented a paper to the Royal Society, 
in which he laid claim to the discovery of the true structure of the placenta and 
its communication with the vessels of the uterus. The following’ is the history 
of the appearances which he observed in the dissection of a woman who had 
died undelivered near the full term of utero-g'estation, and from which appear- 
ances his conclusions were drawn respecting the natural structure of these 
parts. The veins and arteries of the uterus having been injected, an incision 
was made through the parietes, at the anterior part where the placenta ad- 
hered to the internal surface. Between the uterus and placenta lay an irre- 
gular mass of injected matter, and from this mass regular pieces of the wax 
passed obliquely between it and the uterus, which broke off, leaving part at- 
tached to that mass ; and on attentively examining the portions towards the 
uterus, they plainly appeared to be a continuation of the veins passing from 
it to this substance, which proved to be the placenta. Other vessels, about 
the size of a crow-quill, were seen passing in the same manner, although not 
so obliquely. These also broke on separating the placenta and uterus, leaving 
a small portion on the surface of the placenta ; and on examination they were 
discovered to be continuations of the arteries of the uterus. The veins were 
next traced into the substance of what appeared placenta ; but these soon lost 
the regularity of vessels, by terminating at once upon the surface of the pla- 
centa, in a very fine spongy substance, the interstices of which were filled with 
yellow injected matter. He then examined the arteries ; and tracing them in 
the same manner towards the placenta, found that, having made a twisted or 
close spiral turn upon themselves, they were lost on its surface. 
MDCCCXXXII. 
I 
