Circulation of the Blood 123 



heat comes by the arteries, and is the work of the 

 circulation. 



It, therefore, appears to me that the learned Riolanus 

 speaks rather expediently than truly, when in his 

 Enchiridion he denies a circulation to certain parts ; it 

 would seem as though he had wished to please the 

 mass, and oppose none ; to have written with such a 

 bias rather than rigidly and in behalf of the simple 

 truth. This is also apparent when he would have the 

 blood to make its way into the left ventricle through 

 the septum of the heart, by certain invisible and un- 

 known passages, rather than through those ample and 

 abundantly pervious channels, the pulmonary vessels, 

 furnished with valves, opposing all reflux or regurgita- 

 tion. He informs us that he has elsewhere discussed 

 the reasons of the impossibility or inconvenience of 

 this : I much desire to see his disquisition. It would 

 be extraordinary, indeed, were the aorta and pulmonary 

 artery, with the same dimensions, properties, and 

 structure, not to have the same functions. But it would 

 be more wonderful still were the whole tide of the blood 

 to reach the left ventricle by a set of inscrutable passages 

 of the septum, a tide which, in quantity, must corres- 

 pond, first to the influx from the vena cava into the 

 right side of the heart, and next to the efflux from the 

 left, both of which require such ample conduits. But 

 our author has adduced these matters inconsistently, 

 for he has established the lungs as an emunctory or 

 passage from the heart ; : and he says : " The lung is 

 affected by the blood which passes through it, the 

 sordes flowing along with the blood." And, again : 

 " The lungs receive injury from distempered and ill- 

 conditioned viscera ; these deliver an impure blood to 

 the heart, which it cannot correct except by multiplied 

 circulations." In the same place, he further proceeds, 

 whilst speaking against Galen of blood-letting in peri- 

 pneumonia and the communication of the veins : 



1 Lib. iii, cap. 6. 



