164 Mr. Brodie’s Account of the Dissection 
abdomen. At the upper part of the thorax, it sent off the two 
subclavian, and afterwards divided into the two carotid arte- 
ries, without forming an arch. The veins corresponding to 
these arteries terminated in the vena cava, which was situated 
on the anterior part of the spine before the aorta, and passed 
downwards before the right kidney to the right groin. Here 
it became reflected upwards by the side of the urachus to the 
navel, and was continued into the larger vessel or vein of the 
chord. 
It appears therefore, that, in this foetus, not only the heart 
was wanting, but there was no communication of any kind 
between the trunks of the venous and arterial systems, as in 
the natural foetus, where there is a heart. The only com- 
munication between the two sets of vessels, was by means of 
the capillary branches anastomosing as usual in the foetus and 
in the placenta. The blood must have been propelled from 
the placenta to the child through the artery of the chord, and 
must have been returned to the placenta by means of the 
vein, so that the placenta must have been at once the source 
and the termination of the circulation, and the blood must 
have been propelled by the action of the vessels only. 
It is to be understood, that the circulation in the foetus re- 
ceives no propelling power from the action of the heart and 
arteries of the mother. This, although perfectly known to 
anatomists, it is proper to mention, as it may not be equally 
known to all the members of this Society. 
It appears extraordinary, that under these circumstances, 
notwithstanding the circulation through the placenta must 
have been more languid than is natural, that organ should 
nevertheless have been capable of exercising its proper func- 
