2 THE VITAL PROCESSES 



Physiology treats of the function, or use, of the different 

 parts of the body the work which the parts do and how 

 they do it and of their relations to one another and to 

 the body as a whole. 



Hygiene treats of the proper care or management of the 

 body. In a somewhat narrower sense it treats of the 

 " laws of health." Hygiene is said to be personal, when 

 applied by the individual to his own body ; domestic, when 

 applied to a small group of people, as the family; and 

 public, or general, when applied to the community as a 

 whole or to the race. 



The General Aim of Hygiene. There are many so-called 

 laws of health, and for these laws it is essential in the 

 management of the body to find a common basis. This 

 basic law, suggested by the nature of the body and condi- 

 tions that affect its well-being, may be termed the Law of 

 Harmony: The mode of living must harmonize with the 

 plan of the body. To live properly one must supply the 

 conditions which his body, on account of its nature and 

 plan, requires. On the other hand, he must avoid those 

 things and conditions which are injurious, i.e., out of 

 harmony with the body plan. To secure these results, 

 it is necessary to determine what is and what is not 

 in harmony with the plan of the body, and to find the 

 means of applying this knowledge to the everyday prob- 

 lems of living. Such is the general aim of hygiene. 

 Stated in other words : Hygiene has for its general aim 

 the bringing about of an essential harmony between the 

 body and the things and conditions that affect it. 1 



1 The body is affected by what it does (exercise, work, sleep) , by things taken 

 into it (food, air, drugs), and by things outside of it (the house in which one lives, 

 climate, etc.). That phase of hygiene which has for its object the making of the 

 surroundings of the body healthful is known as sanitation. 



