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GERMINATION 



In the case of the human telephone system, if I may call 

 it so, it is only required that A (ear) should be able to signal 

 to B (brain). The latter sends out messages or impulses 

 by the " open " circuits of the motor and secretory nerves 

 to actuate muscle and stimulate gland, so that we have 

 merely to delete the receiver in the sensory circuit at A 

 and suppose that at B to be muscular fibre or gland, to 

 make the analogy fairly complete. We shall, however, 

 have to modify our connections to meet the altered condition. 



Old 





The third figure is, of course, purely speculative. It 

 divides that part of the brain with which we are concerned 

 into three areas, a, b, and c. : a, we will call the sensory 

 receptive area, i.e., that portion of the brain which receives 

 impulses from the sensory nerves ; b, is an imaginary zone 

 charged directly by the blood-stream, and c, the motor 

 area, provided with apparatus for dispatching messages 

 by the motor and secretory paths ; a species, in fact, of 

 departmental telegraph office. 



All these areas, as well as the lung generating station, O, 

 and the muscular fibre, m, are to earth (air) through the 

 resistance of the medullary sheaths and lipoid coatings of 

 the nerves, and the skin — that of the scalp being particularly 

 high — so that we have a " closed " circuit from the trans- 

 mitter at A to area a at B, but an " open " one from area 

 c at 5 to the muscular fibre, m. 



So far we have spoken of circuits, but it is necessary to 

 study the construction of the telephone itself, because in that 

 instrument, as well as in the ear, there is an arrangement 



