186 ERRORS ATTRIBUTED TO ARISTOTLE. [LECT. 



venous trunks and their sharper demarcation from 

 the auricle. Galen, however, perhaps more con- 

 sistently, regarded the left auricle also as a mere part 

 of the " arteria venosa." The canal which leads from 

 the right cavity of the heart to the lung (or, as Aris- 

 totle puts it (E), from the lung to the heart) is, without 

 doubt, the pulmonary artery. But it may be said 

 that, in this case, Aristotle contradicts himself, inas- 

 much as in (P) and (Q) a vessel, which is obviously 

 the pulmonary artery, is described as a branch of the 

 great vein. However, this difficulty also disappears, 

 if we reflect that, in Aristotle's way of looking at the 

 matter, the line of demarcation between the great 

 vein and the heart coincides with the right auriculo- 

 ventricular aperture ; and that, inasmuch as the 

 conical prolongation of the right ventricle which 

 leads to the pulmonary artery (R.v' in the Figure), lies 

 close in front of the auricle, its base may very easily 

 (as the figure shows) be regarded as part of the 

 general opening of the great vein into the right 

 ventricle. In fact, it is clear that Aristotle, having 

 failed to notice the valves of the heart, did not dis- 

 tinguish the part of the right ventricle from which 

 the pulmonary artery arises (R.v') from the proper 

 trunk of the artery on the one hand, and from the 

 right auricle (R.a) on the other. Thus the root, as 

 we may call it, of the pulmonary artery and the right 

 auricle, taken together, are spoken of as the " part of 

 the great vein which extends upwards" (P) ; and, as 

 the vena azygos (Az) was one branch of this, so the 

 " vein to the lung " was regarded as another branch of 



