THE NATURE OF FATIGUE 195 



demonstrated in fatigued animals the existence of a fatigue toxin, differ- 

 ent from simple carbon dioxide and lactic acid and allied to the toxins 

 produced by bacteria. He claims to have extracted this in a pure form, 

 and upon successive injections of it for a period of time into the bodies 

 of other animals their tissues have produced, he claims, an antidote to 

 it in the form of a real antitoxin. This antitoxin of fatigue, if ad- 

 ministered to fatigued animals or even human beings, is said to bring 

 about prompt recovery; if administered to fresh organisms it is said to 

 greatly prolong their working period. I am not prepared to deny the 

 truth of these claims, but such striking discoveries should be confirmed 

 by other investigators before one can fully believe in their reality. It 

 may be said that present science knows no safe, quickly acting, effect- 

 ive antidote to the toxic action of fatigue substances. There can be no 

 doubt, however, about the temporary anti-fatiguing power of certain 

 drugs. The caffeine of coffee and tea is one of these, and the theo- 

 bromine of cocoa is another. Alcohol, too, may act as a temporary whip. 

 When administered to even an isolated muscle, in small quantity, it 

 augments activity, quickens contraction and delays fatigue; in large 

 quantity it is depressing and hastens fatigue. In these respects alcohol 

 is not unlike the physiological fatigue substances. It is undoubtedly 

 useful in very brief emergencies involving fatiguing effort, but like 

 other drugs its usefulness lies outside the normal physiological life of 

 the individual. 



Besides the more purely physiological and psychological aspects of 

 fatigue, it has an important relation to many sociological problems. 

 In its milder form it may be regarded as a blessing, since it leads to 

 healthy rest. But if its warnings are not heeded, it may prove a 

 serious affliction. By reason of its inhibition of activity it is a potent 

 sociological force. It is one of the causes of misery and poverty and 

 disease; it is an inciter of crime; it has helped to lose battles; it has 

 limited industrial expansion. Professor Irving Fisher has recently 

 estimated the minimum annual cost of serious illness in this country 

 as one and a half billion dollars, and says : " The economic waste from 

 undue fatigue is probably much greater than the waste from serious 

 illness." Fatigue must be reckoned with in all human activities, and 

 its toll must be rigidly paid. Happy is he who has the power so to 

 direct his bodily machine as to obtain from it its highest efficiency. 



