SENSE OF SMELL IN FISHES. 349 



Aristotle was acquainted with most of these facts, and even This known to 

 recite^ them at large in his History of Animals: yet he-^"^^^'^ 

 says positively, " fishes have no distinct organ of smell, for 

 there is but one orifice to the apertures they have in the 

 place of the nostrils." And elsewhere, " we see in them 

 no external organ of hearing or smell, not even an aper- 

 ture.'* Mr. Schneider, in his Synonimes of Artedi's 

 Fishes, reproaches Aristotle with entertaining this opinion, 

 after having so well described the olfactory organ and nerves 

 in these animals. It is in some measure therefore a defence whose opinioa 

 of Aristotle's opinion, if I endeavour to show, that every '^ ^^^ ^ ' 

 emanation in water must produce on the nerves, with 

 \^hich it comes into contact, a sensation analogous to that 

 of taste. 



Since there are no real smells in water, the exhalations, The organ of 



that escape from bodies immersed in it, either rise to the ^"^^'^ ^°"J*^, '^ 

 / ' useless to nsh«. 



surface in the form of gas, and consequently do not re- 

 main in the liquid; or they are suspended in it or combined 

 •with it, and they participate in all the properties of liquids. 

 If however the qualities of these particles, thus dissolved, 

 be perceptible, they necessarily come under the same cir- 

 cumstances as sapid bodies ; and therefore it would be use- 

 less for fishes, which live habitually in water, to be en- 

 dowed with the organ of smell. 



To prove the accuracy of this reasofiing, it is necessary Use of the ner- 



to investigate the use of the nervous apparatus, which has ^'°"^ apparatus 



rr 7 supposed to be 



hitherto been supposed to be intended for the perception of intended for 



smells: and to this I shall proceed, treating it more mi- ^™*^^^'"S* 



nutely than in the beginning of this paper. 



The. cavities termed nasal are always situate before the The nasal ca- 



eyes, in the space between the nasal bones and those of the^'^^f* 5*®" 



•',._., . ^ scribed. 



Upper lip. Sometimes they are m the substance of the 



bones of the nose themselves, or between these and the 



pieces which Artedi has called hypophthalmic. The he- 



terosome fishes, as the pleuronectes, the only animals with 



vertebrae that are not symmetrical, are the only ones that 



have both nostrils on one side of the body, in some on the 



right, in others on the left, and unequal. Lastly, though 



most of these species have these cavities on the top of the 



head, in ihe^ forehead; they arc found beneath, and most 



frequeuily ' 



