CHAPTER VI 



DIGESTION 



The Principal Processes of Nutrition The General Plan of Digestion 

 Mastication The Teeth Preservation of the Teeth A ction of 

 the Saliva The Stomach and the Gastric Juice The Movements of 

 the Stomach Gastric Digestion The Intestines The Bile and 

 Pancreatic Juice Intestinal Digestion Absorption by Means of 

 Blood-vessels and Lacteals The Lymphatic or Absorbent System 

 The Lymph Conditions which affect Digestion The Quality, Quan- 

 tity, and Temperature of the Food The Influence of Exercise and 

 Sleep The Kidneys The Spleen Effect of Alcohol on Digestion, 

 the Liver, and Kidneys 



1. Nutrition. The great design of food is to give nutriment 

 or nourishment to the body. But this is not accomplished 

 directly, as the food must first pass through certain preparatory 

 changes, as follows : (1), Digestion, by which the food is reduced 

 to a soluble condition; (2), Absorption, by which, when digested, 

 it is taken into the blood ; (3), Circulation, which carries the 

 enriched blood to the various parts of the system; and (4), 

 Assimilation, by which each tissue selects from the blood the 

 materials necessary for its support. 



"The human body, unlike all other machines, keeps itself in repair 

 without any apparent effort,- when proper food is taken into the body. 

 If* the functions and composition of food were more clearly understood, 

 there would be fewer cases of failing health in youth and middle age than 

 we now have. There are some persons who realize the importance of this 

 knowledge, and live ' by rule ' to such an extent, that they fail to enjoy 

 the food which is so bountifully provided for us. We must gain all the 

 knowledge we possibly can upon the subject, and learn to use it wisely ; 

 without neglecting the natural guides with which we are gifted." E. 

 RICE. 



1. Design of food ? How accomplished f 



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