254 INFLUENCE OF THE BRAIN ON HEALTH. 



as to send forth a stimulus vitiated in quality, the 

 stomach which receives it will partake in the dis- 

 order, and hence the sudden loathing and sickness 

 so often induced by unexpected bad news, vexation, 

 or alarm. 



Something analogous to this is still more visibly 

 exhibited in the case of the muscles. If the mind 

 be active and decided, the muscles, receiving a 

 strong stimulus, move with readiness and force ; but 

 if the cerebral activity be impaired by bilious de- 

 pression, muscular action becomes slow, infirm, and 

 indolent : whereas, if the brain be excited by strong 

 passion, and the stimulus be impetuous, the move- 

 ments instantly become energetic and decided ; and, 

 if the excitement be carried still farther, the regulated 

 muscular contraction passes the limits of health, and 

 becomes involuntary and convulsive. 



As the quality of the nervous influence depends 

 on the condition of the brain, that which springs 

 from a brain of which all the parts are in sound and 

 vigorous action is the best. Mental indolence and 

 high mental excitement are alike inimical to bodily 

 health ; and consequently our great aim ought to be 

 to secure for every mental power, moral as well as 

 intellectual, that equal and regular exercise from 

 which alone the proper nervous stimulus can spring. 



It is indeed interesting to observe the various 

 effects of the nervous influence, according to the 

 faculties in predominant action at the time it is pro- 

 duced. If the higher feelings have the ascendency, 

 and the more selfish propensities be merely suffi- 

 ciently active to give force to the character, without 

 exciting contention in the mind itself, the nervous 

 influence is the most grateful and efficient which 

 can be imagined for sustaining the healthy co-ope- 

 ration of the whole body. This result follows, 

 because the Creator evidently designed such a state 

 of mind to be the best and happiest for man himself, 

 and therefore took care to surround him with every 

 motive to induce him to enter into it 



