■Nates, ill. 4. . . ' " • 195 



side ; in which case A, would have to be credited with the opinion that artery and vein 

 ■were in direct peripheral communication with each other, and that the surplus' blood from 

 a viscus passed away by one or other vessel, and came back in a circle to the heart. But, 

 in spite of the wording of the passages, I cannot believe that this was A.'s opinion. I have 

 no doubt that he thought that the vessels ended in the viscera, and indeed (D. P. iii. 9,, 5) 

 he expressly says that this is the case in the kidneys. How then is the wor^ Ziexovcrt, 

 which I have rendered, "extend through," to be understood? I think it must mean 

 ."spread throughout the substance " ; the contrast between heart and viscera being that 

 . in the latter the vessel breaks .up into nutrient branches which retain the character of 

 vessels, while in the heart there is' no such breaking up, but the vessels expand into a. 

 reservoir, and lose altogether the character of vessels, while the heart is nourished at the 

 expense of th^ blood in its own cavities (ii. ij Note 18). At the same time there are 

 certainly passages in which Siexovffi has the other sense. Such, for instasce, is the 

 passage {//. A. i. 17, 12) referred to' in Note; 15. That passige I interpret as meaning 

 th&t the hepatic vein, when it reaches the portal eminences of the liver, sends branches into 

 it, which terminate in the substance of that organ, while the rest passes on {Vend porta) 

 and terminates on the walls of the intestine. 



11. I|y the central part is meant, as I take it, the main bulk of the heart in opposition 

 to the apical part, which later on is described as being solid. Possibly, however, the 

 whole of what we call heart may be meant, and be called central, because the pericardium 

 is included in the heart by Aristotle. 



12. Cf ii. I, Note 18. ' . 



13. Alluding to the throbbing of the heart on any strong. emotion, whether pleasant or 

 painful. 



14. Cf. ii. 7, Note 27. Neither the blood, nor yet parts without blood, are sensitive ; 

 but only parts which contain blood, and of these that which first contains bl6od will first 

 be sensitive, that is will be the primary source of sensation. 



15. Galen, however, did sUppose that the liver was the origin of the vessels, in the sense 

 of being the organ in which the blood was formed. Galen founded his opinion upon a more 

 correct view of the vena portas than that entertained by Aristotle. A. apparently thought 

 {H. A. i. 17, 12) -that the vena portse was simply the continuation on the far side of the 

 liver of the hepatic vein, conveying blood Sxora. the heart past the liver to the intestinal 

 parts. The absorbed food passed, as he thought, up the portal veiminto the hepatic"' vein, 

 and so oh to the heart without pause in the liver.- Galen recognised the fact that the 

 absorbed food was converted into blood on its passage, in the liver. 



, 16. And therefore it is not a single organ, such as a dominating part should be. Cf iii. 

 7, Note I. 



17. This correct description of the position of the human heart, though it renders it 

 probable that A. had seen the organ in situ, does not actually prove such to have been 

 the case. For, as Lewas says, A. may have been led to his conclusion by merely feeling 

 the impulse of the heart on the left side ; and Galen in fact {De Usu part. vi. 2) says 

 that the heart is central^ but erroneously supposed to be on the left because the impulse 

 is felt there. There is however, I think, another ground for suspecting that A. spoke 

 from actual inspection of the human heart. He describes the right ventricle as being not 

 only on the right side, but above the rest of the heart, that is anterior to it {H. A. iii. 3, 10). 

 This is true of the human . heart, which is so tilted round as. to bring the right ventricle 

 to the front, but is not the case in other animals {cf. Todcfs Cycl. ii. 578). 



It is not quite true that man is the only animal in which. the heart inclines to the left. 

 A like obliquity exists in the higher quadrumana {Cuvier, Anat. Comp: iv. I97)> and in 

 the mole. 



