GENERAL OUTLINES OF ICHTHYOLOGY. 13 



By all means, therefore, let the fisherman study to keep 

 as far away from the water, and as much out of sight as 

 possible. This is the first of the two golden rules for 

 successful angling. 



Hearing. 



Much has been written at different times by clever ana- 

 tomists * on the subject of the sense of hearing in fish, 

 some denying its existence entirely, and others asserting 

 it in a greater or less degree, the former basing their 

 arguments mainly on the absence, in most species, of any 

 external auricular orifice, and the latter upon the internal 

 structure of the head, and practical experiment. 



The probabilities of the question would appear to be 

 with those who maintain the existence of the sense, for 

 these reasons : 



1. Because all fish, though generally wanting the Eusta- 

 chian tube, and tympanal bones, have internal ears, or 

 sacs which, if they do not answer the purpose of hearing, 

 certainly cannot be proved to answer any other. 2. Be- 

 cause water, though the denser medium, is necessarily 

 more or less impressible by the waves of air, or sound, 

 and a vibration of the one, therefore, cannot but cause a 

 corresponding vibration of the other, water, moreover, 

 receiving the vibration of the ground. And 3. Because 



* See Physiological Researches, by Prof. Breschet (Paris) ; Disser- 

 tation on the Organ of Hearing in Man, Reptiles, and Fish, Geoffrey ; 

 Structure and Physiology of Fishes, Monro ; and the works of Cuvier, 

 Valenciennes, Hunter, and others. 



