192 ERRORS ATTRIBUTED TO ARISTOTLE. [LECT. 



some animals than in man. It is strictly correct, 

 therefore, in Aristotle's words, to say that where the 

 heart and the windpipe are connected " it is hollow." 

 If he had meant to speak of one of the pulmonary 

 veins, or of any of the cavities of the heart, he would 

 have used the terms iropoi or Koi\ias which he always 

 employs for these parts. 



According to Aristotle, then, the air taken into 

 the lungs passes, from the final ramifications of the 

 bronchial tubes into the corresponding branches of 

 the pulmonary blood-vessels, not through openings, 

 but by transudation, or, as we should nowadays say, 

 diffusion, through the thin partitions formed by the 

 applied coats of the two sets of canals. But the 

 "pneuma" which thus reached the interior of the 

 blood-vessels was not, in Aristotle's opinion, exactly 

 the same thing as the air. It was " drfp TTO\V<; pecov KOI 

 aOpoos" ("De Mundo," iv. 9) subtilised and con- 

 densed air; and it is hard to make out whether 

 Aristotle considered it to possess the physical pro- 

 perties of an elastic fluid or those of a liquid. As he 

 affirms that all the cavities of the heart contain blood 

 (F), it is clear that he did not hold the erroneous view 

 propounded in the next generation by Erasistratus. 

 On the other hand, the fact that he supposes that the 

 spermatic arteries do not contain blood but only an 

 aifj,aTwSr)s vypov (" Hist. Ammalium," iii. 1), shows 

 that his notions respecting the contents of the arteries 

 were vague. Nor does he seem to have known that 

 the pulse is characteristic only of the arteries ; and as 

 he thought that the arteries end in solid fibrous bands, 



