236 RULES FOR THE PROPER EXERCISE 



study their bodily structure and functions, and thus 

 learn to preserve longer the health and existence of 

 those whose genius is the source of so many plea- 

 sures to the world at large !" 



Having thus pointed out the evils arising both from 

 inadequate and from excessive mental exertion, it 

 remains for me to direct attention to some of the 

 conditions required for the proper exercise of the 

 brain. 



It seems to be a law of the animal economy, that 

 two classes of functions cannot be called into vigo- 

 rous action at the same time, without one or other, 

 or both, sooner or later sustaining injury. Hence 

 the important rule, never to enter upon continued 

 mental exertion, or to rouse deep feeling, imme- 

 diately after a full meal, as the activity of the brain 

 is sure to interfere with that of the stomach, and 

 disorder its functions. Even in a perfectly healthy 

 person, unwelcome news, sudden anxiety, or men- 

 tal excitement, occurring after eating, will put an 

 entire stop to digestion, and cause the stomach to 

 loathe at the sight of food. In accordance with 

 this, we learn by experience, that the worst forms 

 of indigestion and nervous depression are those 

 which arise from excessive application of mind, or 

 turmoil of feeling, conjoined with unrestrained in- 

 dulgence in the pleasures of the table. In such cir- 

 cumstances, the stomach and brain react upon and 

 disturb each other, till all the horrors of nervous 

 disease make their unwelcome appearance, and ren- 

 der life miserable. Literary men and hard students 

 know this fact from sad experience ; but as they are 

 not aware of the incompatibility of the two processes 

 of active thinking and active digestion going on at 

 the same time, it is extremely difficult to give them 

 a sense of their danger, and to convince them that 

 an hour, or an hour and a half, after a meal is more 

 profitably spent in easy relaxation than in the 



