8 MAN AN ADAPTIVE MECHANISM 



Our research showed that animals subjected to fear 

 without muscular activity showed the same phenomena 

 of exhaustion and the same uniform histologic changes 

 in the brain, the adrenals and the liver, as were shown 

 by animals exhausted by traumatic injury under ether 

 or by the muscular exertion oj running or fighting. It 

 is therefore obvious that these three types of exhaus- 

 tion are similar, the difference being that fatigue from 

 physical exertion results from an integration of the 

 motor mechanism with complete response in activity 

 or obvious work performed ; while shock or exhaustion 

 caused by emotion results from an integration of the 

 nervous mechanism without obvious work performed. 

 In the latter case the exhaustion is comparable to the 

 effect produced in an electric automobile which has 

 been integrated to go ahead by a closed circuit, while 

 the wheels of the machine are held immobile. 



Having demonstrated the apparent truth of the 

 Kinetic Theory for traumatic and psychic shock, we 

 undertook further researches to determine whether 

 this theory explained also the exhaustion produced by 

 infections, by drug stimulants such as strychnin, 

 by toxins, by foreign proteins, by insomnia, by exer- 

 tion, etc. To this end we examined all the organs and 

 tissues of animals exhausted by the bacteria and toxins 

 of infections, by foreign proteins, by drug stimulants, 

 by adrenin, by thyroid extract, by many other 

 activating substances and by insomnia. The results 

 of this study showed that as in shock, histologic 

 changes were produced only in the brain, the adrenals 

 and the liver and that these histologic changes were 

 identical, whatever the cause of exhaustion. We 



