388 



THE HUMAN MACHINE 



tired. This is due to the fact that the body cells, when 

 they do work, give off poisons and these poisons gradually 

 accumulate when we get overtired and cause the feeling of 

 fatigue. No one can do his best work when he is fatigued. 

 The nervous system is shocked by such poisons or by other 

 poisons which we take into the body. One example 

 would be tobacco. The effect of tobacco in general 

 seems very slight. It may give you a smoker's cough, 

 or it may seem to have no effect at all, but case experi- 

 ments made with the same sets of men doing work with 

 and without tobacco show that smoking makes for a loss 

 of efficiency. The same is true with overdoses of alcohol. 

 Here many other experiments where accuracy is needed - 

 such as shooting at a mark or setting type have shown 

 that men without alcohol do much better work and more 

 work than those who have alcohol. 



This apparatus is used to measure fatigue. As the finger is moved it lifts a 

 weight and makes marks on the revolving drum. As the finger grows more and 

 more fatigued the weight is lifted less distance at each effort and the marks grow 

 shorter and shorter. At length the finger cannot be moved and no more marks 

 are made. It has become too fatigued to do any more work. 



