CHAPTER XXIV 

 OUR BODIES 



Among the greatest discoveries of this age of science 

 are those which have to do with keeping well. Our health, 

 our happiness and our success in life depend in large meas- 

 ure on our ability to keep our wonderful bodies in good 

 running order. The work that we do for ourselves, or the 

 service we render others, must be done by our muscles and 

 brain, or by machines and forces they direct. 



Our bodies are the most intricate machines in existence. 

 They consist of millions of parts, grouped in a few large 

 systems, each having its particular work to do. A portion 

 of that work is to help and co-operate with the other sys- 

 tems. If one system gets out of order, it is certain to up- 

 set others. 



Our bodies must be given the right food. They must 

 be safeguarded from dangerous matter and from injuries, 

 and protected from weather. They must be used in the 

 right way to produce efficient results. So well has science 

 been helping us to do these things that today our bodily 

 machines, on the average, are lasting many more years 

 than those of former generations. 



In order to know how to use and safeguard our bodies, 

 it is highly important to know what has been discovered 

 regarding their structure and methods of performing their 

 work. 



Sensation and motion enable people to adjust themselves to 

 the outside world. Sensation is the means of learning about our 

 surroundings through our five senses. Motion is the means we 

 have of changing our position. 



The functions of nutrition include respiration, food-taking, 

 digestion, absorption, circulation, assimilation and excretion. 

 There is also the function of reproduction. 



The human body is similar to a lifeless engine in several 

 respects. Both require fuel, or food, and air in order to do work ; 



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