Notes. \\. lo. . 177 



He refuses to admit that the nasal passages in these animals are organs of smell because 

 they end blindly, and do not lead to the brain. Clearly he knew nothing then of the 

 olfactory nerves of these animals. What he looked for in a sense-organ of sight, hearing, 

 or smell, was not a nerve, but an opening of some kind leading to the inside of the skull. 



On the whole I think it most probable that by it6pot. in this place A. means no more 

 than openings or foramina by which the sense-organs are in communication with the 

 interior of the skull ; in the eye, the optic and other fissures or foramina of the orbit ; 

 in the ear, the external and internal meatus ; and in the nose, the anterior nares and 

 possibly the ethmoidal foramina, which he may have noticed, small as they are, in a 

 dog's skull ; though I am by no means sure he may not have thought the communication 

 was completed by the Eustachian tube, with which he was acquainted. {^. A. i. II, 2), 

 a view which would explain his statement that the olfactory itipoi, no less than the 

 auditory, are full of hot air. 



The various foramina or passages place the sense-organ in communication with the 

 vascular membrane that surrounds the brain, and the connection with the heart is 

 completed by means of the blood-vessels that run to it from this membrane. So I 

 interpret the words, "These vipoi lead into the small vessels which extend from the 

 heart to the brain and surround this latter " (Z>. G. ii. 6, 32). 



The difficulty of interpreting A.'s exact meaning is probably due to the fact that he 

 was himself not quite certain as to the channels by which he supposed the ear and 

 nostrils to communicate with the inside the skull. For his account of the auditory 

 ■jTtJpos differs in each of the three main treatises. In the Hist. An. (i. II, 2) it is positively 

 asserted that there is no vipos leading to the brain from the inner ear, there being 

 however a blood-vessel which connects the two, and a ttlpos (the Eustachian tube) 

 running to the mouth. Here in the De Partibus he speaks of a iro'poy running from the 

 ear to the empty space in the occiput ; while in the Z>^ Generaiione (ii. 6, 32) he says 

 that it runs to the vessels on the surface of the brain, 



20. The argument is this : The channels from the eyes end in the blood-vessels 

 outside the brain, and blood itself is insensible. The channels from the ears end in 

 the void space, where there are no blood-vessels ; and no part without blood-vessels 

 is sensitive. Neither the sensibility of the eyes nor that of the ears can therefore be 

 explained simply by their connection with the interior of the cranium. 



The last sentence in this paragraph with its empty repetition is, I doubt not, an 

 interpolation. 



21.' Gf. Note 10, and ii. 8, Note 2. 



22. The sense of taste "appears to have a greater analogy to touch .than any of the 

 others, and appears to be as universal, few animals being endowed with touch, but 

 what are most probably also endowed with taste " (y. Hunter). The close connection 

 of touch and taste is shown in the fact that, while the nerves that minister to the 

 other special senses are exclusively channels of their respective special sensations, 

 those which minister to taste are at the same time nerves of ordinary tactile sensibility. 

 This was of course unknown to A., who rests his statement of the similarity of the 

 two senses on the fact that they both require actual contact of the object with the 

 body, whereas the other three senses are affected by distant objects (cf. D. A. H. 10, l). 



23. Alluding to snakes and seals, cf. iv. II, Note 10. 



24. A. explains (/). A. ii. 9, 12) the manner in which respiration is essential to 

 smell, in such animals^ as have lungs, as follows : " Some animals have their eyes bare, 

 and thus see what occurs in the transparent medium directly. Others have their eyes 

 covered with lids, which protect them as the shards protect a beetle's wings, and these 



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