Hearing, and the Ear. 463 



each semitone. Jt is claimed that some of the best musicians can dis- 

 tinguish or even produce as great a number as that or even greater, in 

 the three octaves possible to the human voice. 



While there can be little or no doubt about the function of the scala 

 media as a whole, being the reception and transfer of tones of musical 

 pitch, such function cannot reside exclusively with the fibres of corti, 

 since perception of pitch is possessed by animals destitute of those 

 organs. Probably the function first arose from the circumstance that 

 the sac of the scala media being of different widths at the opposite ends, 

 it would naturally be of a different fundamental at different parts ; so 

 that tones would be selected, one passing through one part, another, 

 another part. These parts subsequently became the track of the cross 

 fibres of the basilar membrane, and at last of the arches of corti. 



The jarring of the endolymph of the canals and of the scala media 

 constitutes the last of the mechanical movements of ponderable substan- 

 ces, which up to this point appear to be the essential concomitants of 

 sound stimulations. From this point forward the movement is. the 

 nervous electrical current up the auditory nerve and the polar disturb- 

 ance of certain brain cells, constituting the sense of hearing. 



Since polar disturbances and nerve currents are accidents of Ether, and 

 since Ether is everywhere, it is reasonably probable that the nerve cur- 

 rent is a continuation of a previous ethereal movement begun at the body 

 emitting the sound in the first place, and accompanying the vibrations 

 of air to the ear drum, and of the bones to the fenestra ovalis and the 

 endolymph. The form of the motion of the Ether differs with its en- 

 vironment. In the embrace of pulsating air it is a pulsation, in a nerve 

 it is a current. 



The common quality of the organic matter of which all the classes of 

 animated nature are composed, is to some extent proved by the fact that 

 all animal ears have been differentiated by the same octaves. It has 

 been suggested by an ingenious writer 1 that the hearing of insects is 

 adapted to the octaves above ours, and their sensation of continuous sound 

 begins at say 3,000 vibrations per second, while ours ends about there 

 and begins at 32. He reasons from the size of the hearing organs of 

 insects. But we are to consider that it is the sounds of the environment, 

 the sounds to which the animal organism is most exposed, that develop 

 the sense of hearing. These sounds are such as he makes himself ; 

 the calls and signals from one to another, the noises by which the 

 presence of an enemy or the prey is betrayed. A man who can hardly 

 hear the voices of his fellows is partially deaf and must use an ear 

 trumpet to help out his defective hearing apparatus. Like him would 

 be the humble-bee that could not hear a hum, the ericket to which u 



1 Mattieu Williams " Current Discussions iii Science." 



