74 PHYSIOLOGY AND HEALTH. 



they suffer in consequence, and are unable to pursue their 

 studies with their original vigor. A freshman in college 

 endeavored to support his body with eight ounces of bread 

 a day, without other vegetable food or meat. He followed 

 this plan four weeks, and in that time suffered from head- 

 ache, nervousness, general debility, and indisposition to ap- 

 ply his mind to his books. But on returning to the usual 

 but moderate diet of other students, he regained his usual 

 health and mental vigor. 



CHAPTER XVI. 



Greater Flow of Blood and of nervous Energy to Parts and Organs 

 in Motion, and to Stomach during Digestion. Action in other 

 Parts interferes with Digestion. Mental Labor has the same Ef- 

 fect. Rest requisite after Eating, and before Eating. Gymnas- 

 tic Exercises at Cambridge. 



155. WHEN any one organ or portion of the body is in 

 action, more blood is sent to it, through the arteries, to meet 

 the changes, and supply its waste, and support its powers ; 

 at the same time, there is more nervous energy sent to this 

 part, to quicken its activity. When this unusual flow of 

 blood and nervous influence is toward one spot, there must 

 be proportionably less sent to all the other parts, and conse- 

 quently the rest of the body must be comparatively languid 

 or inactive. No two portions or organs can, then, be kept 

 in the fullest and most vigorous action at the same time, for the 

 extraordinary flow of blood, arid of quickening nervous 

 power, cannot be supplied to both or all at once. 



156. This is particularly applicable to digestion of food 

 in the stomach. While this is going on, the preponderance 

 of blood is towards this organ, to sustain this new action, 

 and furnish the materials of the gastric juice ; consequently, 

 there must be a smaller proportion of blood in the other 

 parts of the body. Upon the same principle, the nervous 



