THE HYGIENE OF NUTRITION 207 



become operative in the case of a person whose digestive 

 abilities have been once reduced by mental depression. 

 Auto-intoxication may be induced and one of the clearest 

 results is a further depression of spirits. In this way a 

 lasting injury may be done and the indigestion which be- 

 gan as the effect of temporary unhappiness may be per- 

 petuated in spite of the return of favorable circumstances. 

 Auto-intoxication may come from errors of diet as well as 

 from emotional causes, and a further discussion of it will 

 be postponed. 



Physical fatigue as well as mental may interfere with the 

 progress of digestion. It is well that the appetite usually 

 flags in times of exhaustion, so that one is in a measure 

 insured against the tendency to overtax weakened organs. 

 But when the fatigue is habitual there is an unfortunate 

 dilemma; the body must have abundant food to support 

 the heavy labor and it is not well able to care for the food 

 eaten. Loss of weight is common when a man is so situ- 

 ated. Deprivation of sleep emphasizes this state of affairs, 

 and by dulling both the appetite and the digestive capacity 

 it proves for many people the surest means of reducing 

 adipose tissue. 



Other possible causes of indigestion may be mentioned 

 briefly. Taking cold is one of these. While the congestion 

 and inflammation which so often follow exposure to drafts 

 and dampness are most frequently centered in the mucous 

 membranes of the nose and throat, a corresponding involve- 

 ment of the alimentary canal is not rare. Diarrheal at- 

 tacks are common in the spring and fall when the weather 

 changes are erratic. They are probably to be classed as 

 intestinal "colds." Another source of alimentary trouble 

 is to be found in uncorrected defects of vision. While 

 headaches are the most persistent symptoms of astig- 

 matism and other ocular imperfections, indigestion is not 

 uncommon, and its disappearance when glasses are worn 

 ms sometimes almost magical. 



Quantity of Food. Is overeating the prevalent error 

 of the race? Is undereating easily possible? These are 



