CHAPTER V 

 THE DIGESTIVE SYSTEM 



lungs, as we have seen in the chapter on the 

 Respiratory System, supply oxygen to the blood and 

 remove certain waste products. The tissues of the body, 

 however, require many other substances besides oxygen to 

 maintain life. 



The needed nutrition is derived from the food we eat. 

 The process by which this food is altered in character 

 and prepared so as to become available and suitable for 

 distribution to the different parts of the body is known 

 as digestion. 



Digestion is one of the most important functions 

 performed in the human system; and any considerable 

 deviation from its regular action has a ruinous influence 

 upon the health. In consequence of the great number of 

 organs concerned in digestion, the process is subject to 

 frequent disturbances; these occur, more or less, in every 

 disease to which the human frame is liable. 



It is only by considering the great end of the digestive 

 process that we can fully appreciate its vast importance 

 to the animal economy. By this process our food and 

 drink are prepared to yield their nutritious particles to the 

 blood, from which all the other fluids, as well as the solids, 

 are made, and upon which our very existence depends. 

 Whenever, therefore, digestion becomes enfeebled, vital- 

 ity must also become weakened; and a long-continued 

 weakness of the digestive organs must produce disease, 

 and ultimately death. 

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