History and Progress of Comparative Anatomij. 359 



artery), are opened, and at once allow the aerated blood {sangtiis 

 spirituosus) to escape and be distributed over the system, and 

 the natural blood to be conveyed to the lungs. It is further re- 

 markable tliat, in liis subsequent account of the structure and 

 uses of tlie lung, he shews that he had formed a very distinct, 

 and on the whole, accui'ate idea of the nature of the process of 

 respiration. " All these uses of the lung," he continues, " my 

 predecessors knew ; but I add another of very great moment, 

 to which they have not even alluded ; — and this is the preparation 

 and almost generation of the vital spirits, which aie finally com- 

 pleted in the heart. The air inspired by the nostrils and mouth 

 is conveyed by the windpipe through the whole lung, in which 

 it is mixed with that blood which, proceeding from the rio-ht 

 ventricle of the heart, is conveyed by the pulmonary artery (vena 

 arterialis) ; for this arterial vein is so large that it conveys blood 

 for other purposes as well as its own nourishment. (This, it 

 may be remembered, is one of the arguments already used by 

 Servet to demonstrate the true use of the pulmonary artery). 

 The blood thus conveyed is agitated by the constant motion of 

 the lung, attenuated and mingled with the air, which also in 

 this collision and refraction undergoes some preparation ; so that 

 the mingled blood and air are received by the branches of the 

 venous artery {arteria vcnalis) and are at length conveyed by 

 its trunk to the left ventricle of the heart; and so well are they 

 mingled and attenuated, that little is left for the heart to do ; 

 and after this slight elaboration, as if it put the final hand to the 

 vital spirits, it then distributes them by means of the aorta to all 

 parts of the body*." In his further prosecution of the subject, 

 he entreats his reader not to be influenced by the authority of 

 Aristotle, but to consider the size of the lung and the pulmonary 

 artery and veins, the last of which is evidently made, he argues, 

 to convey blood noifrovi the heart but to that organ. To these 

 arguments, he adds the fact chat blood is known to proceed 

 from the lungs not by coughing only, scd etiam quia Jloridus 

 est, tennis et ptdcher, ut de sanguine arteriarum quoque Mcerc 

 consiicvertint medici. He concludes by recommending the candid 

 reader who searches for truth, to study the subject in the bodies 



" De Ro Anatomica, lib. xi. cap. 2. 



