174 *. Notes, ii. lo. • . 



of hearing or of smellgig. A smell or a sound sets the medium in motion, and this 

 in turn sets the organ of sense in motion. But .when the substance from which .the sound 

 or smell proceeds is placed directly upon the sense-organ, it produces no sensation. .The 

 same is true of touch, though it is not so evident for reasons to be given hereafter. 

 The medium in the case of sound is air ; in the case of smell it has no designation. 

 For smell is an affection alike of air and of water. Just as any transparent substance 

 is a medium for colour, so smell can occur in either water or air. For even water 

 animals appear to have this sense " {JD. A. ii. 7). 



11. Cf. De Sensu, 2. The eye is placed near the brain, because the eye is developed 

 from it (Z>. G. ii. 6, 33) ; the ear, because it requires to be near the space in the occiput' 

 which is full of air ; the organ of smell, because smell is of a hot character and so can 

 temper the coldness of the brain {De Sensu, 5, 18). All three senses, moreover, derive 

 advantage, as stated further on in thjs chapter (-see also iv. 10, 4), from being- in a part 

 where the blood is pure, and heat moderate. Can A. possibly have felt satisfied v/ith 

 this explanation? 



12. Not so. In some Annulosa there are ocelli on the gills, on each segment, or 

 even on the tail. Scallops, ag^in, have eye-specks on the edge of the mantle ; and 

 star-fishes at the ends of their rays. A. thought that scallops could see {H. A. iv. 8, 32), 

 though he had not made out their eye-specks. 



13. One might suppose from this passage that the excavations near the anterior part 

 of the snout, which constitute in fishes the external organs of smell, had entirely 

 escaped A.'s notice. But this was not so, as appears from a passage {H. A. iv. 8, 9), 

 where he mentions these recesses, and says that some Consider them to be organs of 

 sense. This, however, he will not admit, because " the passages (iropoi) do not appear 

 to lead .to the brain, but are either blind or lead to the gills. " His notion was that in 

 fishes the gills were the external •organs of smell (cf. ii. 16, Note 10) ; and his reason 

 for so thinking appears to have been this. In man the' nostrils serve for the admission 

 of air, and at the same time for olfaction. In fishes the gills serve for the admission of 

 water, and so correspond to the nostrils, the water in fishes and the air in man serving 

 one and the same purpose, viz. refrigeration. Finding this correspondence in one point 

 between gills and nostrils, A. assumed that they corresponded in other matters, and so 

 assigned to the gills the olfactory duties of the nostrils. Similarly he supposed that 

 CetAcea smell by the blow-hole, though he did not apparently recognise the fact that 

 this corresponds anatomically to the nostrils ; and, 'again, that in insects the same part 

 .served for smell as for cooling the body. That fishes can smell A. inferred from their 

 refusing as a rule to .take stinking bait ; and that they can hear, from th6 care which 

 fishermen have to take to avoid making a noise with oars or nets when they approach 

 a shoal {ff. A. iv. 8, 15). There is no communication in fishes between the internal 

 ear and the outer surface ; and the existence of the internal ear entirely escaped 

 Aristotle's notice. He nowhere says how he supposes fishes to hear. 



14. Cf. ii. 7, Note 4. ' ' 



15. Cf. ii. I, Note 12, 



• 16. " The fapulty of sight does not belong to the eye, because it is of water, but 

 because it is transparent, a quality which exists in air no less than in water. But water 

 is less elastic, and more easily kept in place than air, and on this, account the eye is 

 made of it That the eye is made of it, is manifest from the fact, that water runs 

 out of it when it is ruptured" {£>e Sensu, ch. 2, 12). ' 



17". Cf. ii. 7, Note 12. . . < 



18. There are in this chapter, as in other passages, three very strange statements 



