274 THE FARMER OF TO-MORROW 



else. The result is all the same, generally 

 speaking. If the laborer is tired out by one 

 form of muscular exercise, give him a task 

 that brings into play different muscles and he 

 will be able to continue work. 



This fact is recognized by the so-called ef- 

 ficiency engineers of the present day. They 

 urge that laborers be given a rest every few 

 hours, and, in addition, that they be given a 

 change of employment occasionally. This 

 runs counter to the old theory of division of 

 labor, that a man is most efficient if he be per- 

 mitted to do the same thing all the while. The 

 old theory is easily explained by the axiom 

 that practice makes perfect. The new theory, 

 that a laborer should be given change of oc- 

 cupation, is based on physiological reasons, 

 one might almost say pathological reasons. 



The established fact that fatigue can be in- 

 duced by chemical means suggested a new 

 avenue of research to the scientists of the Fed- 

 eral Bureau of Soils, when they cast around 

 to determine the causes of soil fertility and 

 infertility. 



Maybe the soil is tired. Maybe the soil is 

 poisoned. Nature intervenes a season between 

 crops, subjects the soil to freezing, thawing, 



