64 
DR. LEE ON THE STRUCTURE OF THE HUMAN PLACENTA, 
Since the preceding paper was forwarded to the Secretary of the Royal 
Society, the following valuable communication has been received by the author 
from Mr. Owen, to whom portions of the gravid uterus and placenta were sub- 
mitted for minute examination. 
My DEAR SlR, Lincoln’s Inn Fields, 17th November. 
During the time you were examining the Hunterian preparation of the uterus 
and placenta in the Museum of the Royal College of Surgeons, your observa- 
tions on the obscurity produced by the extra vasated injection led me to think 
of some less objectionable mode of demonstrating the vascular communication 
between the uterus and placenta, if it existed; or of proving, more satisfactorily 
than the appearances you pointed out in that preparation seemed to do, that 
there was no such communication. 
You have since afforded me the means, through the kindness of Mr. Alex. 
Shaw, of examining in the manner I wished, the anatomical relations between 
the placenta and uterus. This has been done by dissecting the parts under water 
before disturbing them, either by throwing forcibly foreign matter into the 
vessels, or by separating the placenta from the uterus to observe the appearances 
presented by the opposed surfaces, — -a proceeding which if done in the air is 
liable to the objection of the possibility of having torn the vessels which were 
passing across, and the coats of which are acknowledged, by those who main- 
tain the existence of such vessels, to be extremely delicate. 
The mode, therefore, which was adopted to avoid these objections, was to 
fix under water in an apparatus used for dissecting mollusca, &c., a section of 
the uterus and placenta, and, commencing the dissection from the outside, to 
remove successively and with care, the layers of fibres, and trace the veins as 
they pass deeper and deeper in the substance of the uterus in their course to 
the deciduous membrane ; in which situation as the thinnest pellicle of mem- 
brane is rendered distinct by being supported in the ambient fluid, I naturally 
hoped in this way to see the coats of the veins continued into the deciduous 
membrane and placenta, and to be able to preserve the appearance in a pre- 
paration, if it actually existed in nature. But in every instance the vein, 
having reached the inner surface of the uterus, terminated in an open mouth 
on that aspect ; the peripheral portion of the coat of the vein, or that next the 
