AUTOMATIC TELEPHONE EXCHANGES 253 



trunk calls and get on to subscribers attached to distant 

 centres. 



If you should happen to visit this provincial town, 

 quiet and pleasant enough, you will be surprised to find 

 out at the railway station that the town itself is some 

 miles distant, and if you require a conveyance then you 

 must enter the telephone box and get into communica- 

 tion with the local jobmaster. You take the receiver 

 down and listen. Quite a lady-like voice asks, " What 

 number, please." Through the transmitter you explain 

 you do not know the number, but you want to get into 

 communication with the jobmaster. You may almost 

 hear the operator insert the connecting plugs which put 

 you through to him. His bell rings until his wife comes 

 and takes your order. In half-an-hour you are rewarded 

 by seeing a comfortable carriage draw up at the station 

 gate. We have seen a bolus of food, on reaching the 

 pharynx, use a similar system to procure a conveyance — 

 at least a means of transport (p. 175). When thrust 

 from the mouth a bolus comes in contact with the lining 

 membrane of the pharynx, which is beset with automatic 

 transmitters of the " touch-button " kind. Mere contact 

 is enough to set urgent messages streaming into an ex- 

 change in the medulla ; the connecting plugs, which 

 effect connections automatically in nerve exchanges, 

 transmit these messages to the units or cells — job- 

 masters or drivers — which start and regulate the pharyn- 

 geal carriages ; these driver units issue their orders, and 

 the bolus is immediately seized and carried along the first 

 stage of its journey towards the stomach. 



We may cite one or two other examples which illus- 

 trate the telephone system of the human body. No part 

 of the body is more thickly studded with automatic trans- 

 mitters than the skin of the sole of the foot. When we 

 are standing and walking messages have to be dispatched 

 informing and warning the balancing muscles of the limbs 

 and trunk concerning the poise of the body on the feet, 

 for, as we sway this way or that, the pressure on the skin 

 and on the transmitters is altered, and messages are thus 



