572 THE SENSORIAL FUNCTIONS. 



class of vibrations which, applied to our visual 

 organs, excite no sensation.* The functions of 

 the antennae, which, though of various forms, 

 are organs universally met with in this class of 

 animals, must be of great importance, though 

 obscurely known ; for insects when deprived of 

 them appear to be quite lost and bewildered. 



The Torpedo, the Gymnotus, and several other 

 fishes, are furnished with an electrical appa- 

 ratus, resembling the Voltaic battery, which they 

 have the power of charging and discharging at 

 pleasure. An immense profusion of nerves is 

 distributed upon this organ ; and we can hardly 

 doubt that they communicate perceptions, with 

 regard to electricity, very different from any that 

 we can feel. In general, indeed, it may be re- 

 marked, that the more an organ of sense differs 

 in its structure from those which we ourselves 

 possess, the more uncertain must be our know- 

 ledge of its functions. We may, without any 

 great stretch of fancy, conceive ourselves placed 

 in the situation of the beasts of the forest, and 

 comprehend what are the feelings and motives 

 which animate the quadruped and the bird. 

 But how can we transport ourselves, even in 

 imagination, into the dark recesses of the ocean, 

 which we know are tenanted by multitudinous 

 tribes of fishes, zoophytes, and mollusca ? How 



* Encyclopaedia Metropolitana, Article " Light." 



