418 BIOLOGY. 



solely unto sensation. Now, a system, which converts its 

 function into that of sensation, is a sense. 



2477. The sensorial organ, which simply through 

 motion, or a resistance presented to that of the atoms, 

 produces sensation, or wherein the motion as such is 

 felt, is the Ear. 



2478. The ear is none other than the ultimate deve- 

 lopment of the bone and muscle, when they are brought 

 under the direct dominion of the nerves. 



2479. The auditory ossicles are the limbs subtilized or 

 refined in character. They have joints, are provided 

 with muscles, and move exactly like the limbs. It may 

 be said; that the stapes is the scapula, the incus the 

 humerus, the malleus the fore arm, and the concha with 

 its cartilages, the hand with its digits. 



2480. The ear, like the bulk of the limbs, has origi- 

 nated from branchiae. In Fishes, the auditory ossicles 

 have degenerated into the branchial opercula. 



2481. The ear-trumpet (or Eustachian tube), which 

 opens into the mouth, is the internal branchial aperture. 



2482. The motor system, however, belongs to the 

 trunk, whose viscera are repeated also in the ear, or 

 in a cavity which has been called its labyrinth. The 

 three semicircular canals appear to correspond to the 

 intestine, the cochlea to the trachea. 



2483. The ear has not only a nerve, but likewise a 

 brain, of its own. 



2484. The cerebellum is the auditory brain, and from 

 it the acoustic nerves take their rise. For, since the ear is 

 the sense of the whole motor system, and consequently 

 of half the animal, it inevitably follows, that an appro- 

 priate or special nervous mass must be developed for it, 

 just as the myelon or spinal chord has been for the trunk. 

 An organ, which is so constantly active, must necessarily 

 have a large nervous mass. The cerebellum is conse- 

 quently not a brain in the general sense, but one which 

 is wholly individualized. It participates in the motion, 

 which, as sound, is transmitted to the animal. 



2485. By its signification as well as by its own 



