418 HUMAN PHYSIOLOGY 



injures the brain, and leads especially to weakness of the heart by 

 interfering with its supply of nervous force. Many cases of cancer 

 of mouth and throat are believed to have resulted from tobacco 

 smoking. 



" Opium, for its benumbing influence upon the nerves, is used by 

 large numbers of persons, especially in Oriental lands. Its con- 

 tinued use deranges all the digestive processes, disorders the brain, 

 and weakens and degrades the character. Like alcohol, it pro- 

 duces an intolerable craving for itself, and the strongest minds 

 are not proof against the deadly appetite. 



" Self-control versus Appetite. — Man is a bundle of appetites. 

 Every organ, every cell even, craves its appropriate stimulus. Ani- 

 mals under natural conditions gratify the appetites as they arise 

 only to that extent which is healthful for the whole body. Man 

 alone, whose highly developed brain is overlord to the rest of his sys- 

 tem, permits an unwholesome indulgence of appetite to interfere 

 with this general well-being. Alcohol, opium, and their like are far 

 from being the only substances whose excessive use injures the 

 organism and degrades character. Children are often allowed 

 to indulge a natural fondness for sweets to an extent which is 

 ruinous to digestion; for sugar, which is a useful and necessary 

 food in suitable quantities, in larger ones acts injuriously upon the 

 system. Boys pampered with dainties from infancy logically infer 

 that a fancy for cigars or beer may be similarly gratified. Appe- 

 tite for even the most wholesome food may be in excess of bodily 

 needs, and the practice of gluttony is certain to derange nutrition. 



" A child should be early taught that because he ' likes ' a 

 certain article of food he should not therefore continue to eat it 

 after natural hunger is satisfied, or at times when he does not need 

 food; while to persist. in eating or drinking that which experience, 

 or the advice of those competent to judge, has taught him to be 

 harmful, should be regarded as unworthy a rational being. 



" These are but illustrations of the manifold forms of intemper- 

 ance which work untold harm to the physical and moral natures. 

 There seems no possibility of improvement to our race except 

 as the young are led to recognize the manliness and dignity of 

 controUing one's appetites." — Macy, Physiology, 



