GENERATION OF ANIMALS, V. ii. 



objects perceived, (6) to hear and smell from a dis- 

 tance. As for (a) the abihty to distinguish the 

 differences well, the cause of this is the sense-organ, 

 just as it is in the case of sight, i.e., it must be pure 

 and clean itself, and so must the membrane round it." 

 ['' For the passages of all the sense-organs, as is stated 

 in the treatise Of Sensation, run to the heart, or to 

 the counterpart of it in animals which have no heart. 

 Now the passage of the hearing, since the sense- 

 organ of hearing consists of air, terminates at the 

 point where the connate pneiima causes in some the 

 pulsation, in others, the respiration [and inspiration]. 

 This, too, is why we are able to understand what is 

 said and to repeat what we have heard, for whatever 

 the character of the movement was which entered 

 through the sense-organ, the character of the move- 

 ment caused by means of the voice is the same in 

 its turn — they might be two impressions from one 

 and the same die. So, if you have heard a thing, 

 you can utter it. Again, people hear less well while 

 yawning and breathing out than they do while 

 breathing in. The reason is that the principle of 

 the sense-organ of hearing is situated upon the part * 

 that is concerned with the pneuma, and it is shaken 

 and set in movement when the organ sets the 

 pneuma in movement [since the organ gets set in 



" Cf. De anima II. 420 a 13 : we can no longer hear if the 

 membrane is damaged which encloses the air in the ear, 

 any more than we can see if the skin on the pupil of the eye 

 is damaged. 



* For the diflBculties involved in the following lines, see 

 note, pp. 563 f. For the theories here assumed, see the 

 account of Hvfufurrov IlvevftxL, App. B, especially §§ 26 fF. 



' Viz., the heart; see App. B §§ 31 f., and 776 b 17, 787 

 b 28. 



507 



