THE AUDITORY APPARATUS 



121 



These fluids are separated and, I believe, insulated from 

 each other, are partly carried in what one might almost 

 call coils, and, being in " closed " circuits, are in a condition 

 of constant neuro-electrification. They, in my opinion, 

 act as part of the human induction coil in assisting to convey 

 and regulate the quality of the tone, and in this way the 

 waves of sound impinging upon the drum of the external 

 ear, and amplified and carried by the middle ear, would 

 be received by the primary winding — ^the perilymph — 

 and actuate the secondary — the endolymph — whence they 

 would be transmitted in the form of neuro-electrical vibra- 

 tions or waves to the brain. 



In comparing the auditory apparatus with a direct working 

 telephone it is unnecessary to say that the brain does not 

 reply to the messages it receives from the sensory system, 

 although it acts upon them. We do not, therefore, require 

 a receiver at the ear end. A possible arrangement that 

 obtains we shall see later on. 



^cK 



The next diagram (Figure 83) is of a pair of direct working 

 telephones in a " closed " circuit. It will be seen that the 

 current from the battery, h, flows through both transmitters 

 and receivers in series. When the transmitter at A is 

 spoken into it alters the total resistance in circuit, more or 

 less current flows through the transmitter and receivers 

 and, the effect upon the receiver being approximately 

 proportional to the variation thus produced by the trans- 

 mitter, the diaphragm of the former vibrates in unison 

 with that of the latter and in consequence reproduces the 

 speech-waves. 



