EXCRETION AND FATIGUE 211 



244. Rate of work. When we come to think of it, we 

 shall recall that getting tired is not altogether a matter of what 

 kind of work we are doing; it is partly a matter of how fast 

 we are doing it. "It is the pace that kills " (see Fig. 80). 

 Physiologically this means that at a certain rate or speed 

 fatigue poisons are formed faster than they can be removed 

 by the blood, and from the blood by the kidneys, etc., and 

 that when the work is done at a certain slower speed, the blood 

 can remove the wastes just as fast as they are formed. When 

 you walk very fast, you may feel tired before you have gone 

 a mile, although you are not out of breath ; if you walk slowly 

 enough (but not too slowly), you may walk ten miles without 

 showing any signs of fatigue. 



We may therefore conclude that work can be kept up best 

 if we take the right pace. Work that is speeded may give 

 larger returns in a given time but only for a short time. If 

 the high speed is maintained, the worker will have to stop 

 sooner or the quality of the work will fall off. This principle 

 has its everyday applications in athletics, in play, in housework, 

 in school work, and in industry. 



245. Fatigue and efficiency. When Frederick W. Taylor, 

 the founder of scientific management, wanted to increase the 

 output of useful work on the part of some unskilled workers, 

 he did not urge them to work faster. Instead, he carefully 

 experimented to find out how fast the necessary movements 

 could be performed without accumulating fatigue poisons 

 during the hours of work. He actually made the men move 

 more slowly than they had been accustomed to. And in 

 shoveling dirt and carrying pig iron he more than doubled the 

 day's work without increasing the day's fatigue. This principle 

 is so well recognized among the leaders in scientific manage- 

 ment of works that the efforts of the experts are directed to 

 devising plans that will prevent fatigue on the part of the 

 workers. These plans usually contain two sets of factors, one 

 mechanical and the other biological. 



