CHAPTER XVII 

 STRUCTURE OF THE NERVOUS SYSTEM 



Coordination and Adjustment. If we consider for a 

 moment the movements of the body, we cannot fail to 

 note the cooperation of organs, one with another. In the 

 simple act of whittling a stick one hand holds the stick and 

 the other the knife, while the movements of each hand are 

 such as to aid in the whittling process. Examples of co- 

 operation are also found in the taking of food, in walking, 

 and in the performance of different kinds of work. Not 

 only is cooperation found among the external organs, but 

 our study of the vital processes has shown that the princi- 

 ple of cooperation is carried out by the internal organs as 

 well. The fact that all the activities of the body are 

 directed toward a common purpose makes the cooperation 

 of its parts a necessity. The term " coordination " is em- 

 ployed to express this cooperation, or working together, of 

 the different parts of the body. 



A further study of the movements of the body shows 

 that many of them have particular reference to things out- 

 side of it. In going about one naturally avoids obstruc- 

 tions, and if anything is in the way he walks around or 

 steps over it. Somewhat as a delicate instrument (the 

 microscope for example) is altered or adjusted, in order to 

 adapt it to its work, the parts of the body, and the body 

 as a whole, have to be adjusted to their surroundings. 

 This is seen in the attitude assumed in sitting and in 

 standing, in the position of the hands for different kinds 



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