AUTOMATIC TELEPHONE EXCHANGES 265 



units were sensitive to impressions, the stimulus which 

 caused one of them to contract, spread slowly as a wave, 

 from the point which was touched. In the specialised 

 governing units which make up a nervous system, sensi- 

 tiveness and the power to conduct a message wave became 

 their sole duty in life. These highly specialised governing 

 units were grouped together in great central departments, 

 which are represented by the brain and spinal cord — 

 the governing system of the human machine. In our 

 bodies one unit out of every fifty is a government 

 servant or master. 



The high degree of specialisation seen in modern 

 national machines has been rendered possible by inventors 

 who discovered methods of improving communication. 

 A modern nation could not move as a machine if it were 

 deprived of its roads, its railways, its steamers, and 

 its cable, telegraph, and telephone systems. In recent 

 centuries one improvement followed fast upon another, 

 each serving to link the individuals of a nation more 

 closely together so that they could act as a single 

 machine. In early days paths beaten by the feet of 

 British natives had to serve the tribal messenger ; roads 

 and mail-coaches came in due season ; railways and 

 telegraphs followed, and quite recently appeared the all- 

 pervading ramifications or the telephone system. We 

 have seen that the human machine has passed through 

 corresponding phases, from the slow postal traffic carried 

 in the blood circulation to that triumph of rapid communi- 

 cation — the nerve system. There is one striking differ- 

 ence, however, in the organisation of a national machine 

 and a human machine. The government officials of a 

 nation, as well as plain citizens, use freely both telephone 

 and telegraph systems in carrying out their duties. But 

 in the human body the whole system of rapid -com- 

 munication has been made a government monopoly. 

 All its telephone exchanges are manned by government 

 officials. The humble units which carry on the pro- 

 ductive industries of the body may dispatch messages 

 which are intended for another set of workers, but these 



