OF THE BRAIN AND MIND. 237 



abour of composition. As regards the lower ani- 

 mals, indeed, we are careful enough to observe this 

 organic law ; for we do not allow our horses or 

 dogs to be actively exercised till digestion is in some 

 degree completed. 



It may be said that mechanics, labourers, and 

 others hurry away to work immediately after meals, 

 and that, in the United States, the practice of hastily 

 swallowing dinner and instantly returning to busi- 

 ness is proverbially common. My answer to this 

 objection is simply, that experience proves the fact, 

 that digestion goes on better when exertion is re- 

 frained from and repose is enjoyed, and that the 

 tendency to sleep and inactivity which besets most 

 animals after a full meal shows repose to be, in such 

 circumstances, the intention of nature. It must be 

 observed also, that the bad effects of immediate ex- 

 ertion are not of that description which ensue in- 

 stantly, or are felt from day to day. These may 

 show themselves only at the end of months or 

 years, when the influence has, as it were, accumu- 

 lated by repetition. Although, therefore, the sys- 

 tem possesses a certain power of resistance, and 

 many persons seem to escape even for years, it 

 cannot be doubted that opposition to the law of na- 

 ture will eventually prove injurious. The extreme 

 prevalence of dyspeptic complaints and of insanity 

 among the Americans is, in all probability, partly 

 owing to the very practice which is supposed by 

 some to be harmless to them. 



The time best adapted for mental exertion falls 

 next to be considered. Nature has allotted the 

 darkness of night for repose, and the restoration by 

 sleep of the exhausted energies of mind and body. 

 If study or composition be ardently engaged in to- 

 wards that period of the day, the increased action 

 in the brain which always accompanies activity of 

 mind requires a long time to subside ; and, if the 

 individual be at all of an irritable habit of body, he 



