366 PHILOSOPHICAL TRANSACTIONS. [aNNO I767, 



inferior. In this manner one conceives how this subject could do without a 

 heart, the umbilical blood being a continuation of that from the arteries of the 

 placenta, the uterus, and in short of the mother; the impulsion of the maternal 

 blood was propagated by that aorta through all its ramifications, both above and 

 below. In short, the heart of the mother supplied that of the foetus, and the 

 circulation in this was a continuation of that of the mother. These are the 

 reasons inclining him towards that first opinion ; and here are those that sus- 

 pended his judgment for some time in favour of the supposition of a communi- 

 cation of the umbilical vein with the trunk, of the vena cava of the foetus. 1. 

 In every foetus the umbilical vein empties itself into the vena cava in the liver; 

 therefore nature has here followed her usual course. 2. With regard to the arte- 

 rial trunk e, it is close by the division of the iliac vein ; whence it is very likely 

 that it was the left iliac vein which was divided. 



This last, and most striking reason, made him employ almost a whole morn- 

 ing in looking over and over this left iliac region, to discover the divided vessel, 

 which would have put the whole matter out of dispute ; but he could find no 

 trace or appearance of it. All the vessels communicating with the left umbilical 

 vein appeared very entire, though deprived of part of their ramifications by which 

 the air escaped, but all grew in their course less and less in diameter. Which 

 then was the origin of this left umbilical artery ? doubtless the branches of the 

 trunk of the aorta, which were numberless in the pelvis, but had partly been 

 spoiled the preceding night, in dissecting the rectum, uterus, and bladder of this 

 monster. He adds, that this trunk was joined to some membranes, which he 

 was obliged to pull about, to make it turn to the left, and this direction appeared 

 not to be its natural position. 



Be it granted for a moment, that e is the left iliac, and that the umbilicjil vein 

 joins it at d; how could the blood circulate in this foetus? How could it have 

 lived the Q months? d is evidently a trunk of the cava, which generally enters 

 the right auricle of the heart, dividing, like this, into the cava superior, d, b, 

 which rises by the vertebrae up to f, and into the cava inferior, d, g. 1 . It 

 would be absurd to place the only moving power of circulation in the vena cava, 

 or indeed in any vein. 2. When you have placed it there, what will this suppo- 

 sition tend to? 3. This vein subdivides, and ramifies itself through the kidney 

 liver, the muscles and the spine; but none of its branches v^ommunicate with the 

 aorta. The aorta on its part sends several branches into the kidney liver, very 

 slender, and resembling, by their transversal direction, the common emulgents, 

 but very- different in size. If then the circulating force were placed at d, it could 

 only produce an inverse circulation, by the communication the cava might have 

 by its capillary branches, with the like ramifications of the aorta, which suppo- 



