THE GENERAL PROBLEM OF KEEPING WELL 393 



drugs as well as from the practice of any form of activity 

 known to be harmful to the body. 



9. Of elimination: Observe all the conditions that 

 favor the regular discharge of waste materials from the 

 body. 



Obedience to these laws is of vast importance in the 

 proper management of the body. They should, indeed, 

 be so thoroughly impressed upon the mind as to become 

 fixed habits. There are, however, other conditions that 

 relate to this problem, and it is to these that we now turn. 

 These conditions have reference more specifically to 



The Prevention of Disease. While the average length of 

 life is not far from thirty-five years, the length of time which 

 the average individual is capable of living is, according to 

 some of the lowest estimates, not less than seventy years. 

 This difference is due to disease. People do not, as a rule, 

 die on account of the wearing out of the body as seen in 

 extreme old age, but on account of the various ills to 

 which flesh is heir. It is true that many people meet 

 death by accident and not a few are killed in wars, but 

 these numbers are small in comparison with those that 

 die of bodily disorders. The prevention of disease is the 

 greatest of all human problems. Though the fighting of 

 disease is left largely to the physician, much is to be 

 gained through a more general knowledge of its causes 

 and the methods of its prevention. 



Causes of Disease. Disease, which is some derangement 

 of the vital functions, may be due to a variety of causes. 

 Some of these causes, such as hereditary defects, are re- 

 mote and beyond the control of the individual. Others 

 are the result of negligence in the observance of well- 

 recognized hygienic laws. Others still are of the nature 

 of influences, such as climate, the house in which one 



