Lungs to the Aorta , and from thence again by the Umbilical Arteries to the Veins of the Uterus , making a sort of Epicycle to the main Circulation in the Mother.
As this Opinion is Favour'd by the Structure and Disposition of the Blood-Vessels on both Parts, so there is nothing in it difficult to be conceiv'd, or repugnant to Experience. Late Discoveries have made it appear, that the Arteries and Veins are continu'd Tubes, and that the latter contain nothing but what they receive from the former, and no Reason appears why
we shou'd think this Method to be varied in the Placenta. On the other hand, if the Arteries of the Uterus were continued to the Veins of the same part, and those of the Fœtus in like manner, without communicating with each other, their Confluence in the Placenta seems to be altogether impertinent, and of no use, and the Umbilical Arteries and Vein fram'd for no other Service or Purpose, than to give the Blood room for an idle Sally.
Thus the Reasonableness of this old Opinion may be vindicated, but the Certainty of it rests upon stronger Proof. Mr. Cowper, to whose happy Industry we owe the Confirmation of many ancient Discoveries, and the Benefit of some new ones, has the Honour to re-establish this old, but long exploded Truth. For by pouring Mercury into a Branch of the Uterine Arterie of a Cow, that went into one of the Cotyledones of the Uterus, he fill'd those Branches of the Umbilical Veins, which went from that Cotyledon to the Navel of the Fœtus; which, with a part of the Uterus, he keeps prepared by him.
It would be a weak Objection, to alledge, That the Observation and Experiment being made on the Uterus of a Cow , the Inference would not hold from thence to a Woman , the one being Glanduliferous , and the other Placentiferous ; since every one of these Cotyledones , or Uterine Glandules , is