CHAPTER VI 



SELF-PKESEKVATION AND THE MENTAL LIFE 



I 



ENOUGH has been said of the nature of physical 

 disease and of its various causes to show how mani- 

 fold are the influences that must be taken into 

 account in any intelligent effort to prolong human 

 life under conditions of maximal bodily efficiency. 

 It now remains to consider the mental influences that 

 affect the duration of life and, what is equally im- 

 portant, the satisfaction and efficacy of the mental 

 experiences that enrich consciousness. I have tried 

 to give the reasons for thinking that the gap between 

 mental activity and physical activity is not so wide 

 as is generally supposed, and that consciousness 

 itself must be regarded as the expression of the most 

 refined form of physical activity, a form of activity 

 subserved by an extremely complex type of machinery 

 which transforms and liberates energy under condi- 

 tions at present undefinable, owing to lack of experi- 

 mental knowledge. I shall try to show here that the 

 mental life, or the content of consciousness, stands in 

 the most intimate relation conceivable to physical 

 conditions, partly inherent in the organization of 

 the brain, and partly dependent on fleeting stimuli 

 brought to the brain from without. 



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