THE HUMAN BODY, 



CHAPTER I. 

 DEFINITIONS. 



SECTION I. 1. If we wish to study a machine, such 

 as a clock or a steam-engine, we take it to pieces, and ex- 

 amine each part separately. We inquire what each part 

 is called, what it is made of, and how it fits in with the 

 other parts. We then ask what is the use of each part, 

 and how it works. Knowing these things, we understand 

 the machine and its action. 



2, The human body, which is the most wonderful of 

 all machines, is to be studied in this way. 



Anatomy names and describes its parts. It tells us 

 their size, weight, shape, color, texture, and composition ; 

 their position, and relation to other parts. 



Physiology acquaints us with the action of each part, 

 and the work that it does. It tells us how it acts, when 

 it acts, what makes it act, and what is the effect of its 

 action. 



Anatomy may be studied in the lifeless body. 



Physiology must be studied in the living body. 



Anatomy is well known, because all the parts of the 

 body have been carefully studied and described. 



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