26 ELEMENTS OF PHYSIOLOGY 



since we cannot understand the functions or the actions of an 

 organ without knowing its form and structure. But if we 

 go no further than these sciences, we may as well be study- 

 ing the position of the stars in the constellation of Orion 

 so far as practical benefit to our lives is concerned. There 

 is a third science based upon the other two, called Hygiene, 

 or the Science of Health. It treats of the proper surround- 

 ings for healthful living, and of the activities of the body 

 necessary for the perfect performance of all its functions. 

 It is in Hygiene that Anatomy and Physiology find their 

 practical application. 



40. The study of the human body should give the follow- 

 ing results : 



1. It should be a means of intellectual training through 

 the attempt to master its facts, solve its problems, and 

 comprehend the relations of its parts. 



2. It should be a source of pleasure in leading us to real- 

 ize the wonders of our bodily structure and the wonderful 

 adaptations of the body to the surrounding conditions. 



3. It should give a thorough knowledge of one vertebrate 

 animal that would greatly aid in studying other animals. 



4. It should give knowledge which, rightly applied, would 

 form a basis for intelligent care of the health. It should 

 thus be a training in " common sense," which expression 

 taken in its original meaning denotes "sense about com- 

 mon things." We see why physiology, if studied thought- 

 fully, affords a better training in common sense than almost 

 any other study, when we remember that health is the 

 commonest of all subjects for observation and conver- 

 sation, and that every habit and surrounding condition of 

 life affects the health. 1 



41. Cells. While studying the skin, reference was 

 made a number of times to the cells of which it is chiefly 



1 To a person who is destitute of common sense, or who fails to use his 

 common sense while studying this subject, it may become the occasion of 



