260 INTRODUCTION TO GENERAL SCIENCE 



The amount of food consumed does not determine whether 

 a person is to receive great or little good from it. The diges- 

 tion and assimilation of the food are what count. Many thin 

 persons have enormous appetites, while some fat persons eat 

 but little. 



References : 



1. 1304:370-371. Food Supply. 



2. 1501 : 131-134. Quantity of Food Required. 



3. 1503:20-22. Foods. 



4. 1503:317-324. Foods. 



5. 1702 : 374-392. Rational Feeding of Men. 



6. 1710:117-125. Use of Foods. 



7. Farmers' Bulletin No. 142. Principles of Nutrition and Nu- 



tritive Value of Food. 



a. 1505 : 91-93. The Four Kinds of Nutrients. 



b. 1506 : 35-45. Food and its Uses. 



c. 1507 : 37-61. Foods and Food Habit. 



d. 1509 : 65-72. Selection and Preparation of Foods. 



e. 1510 : 51. The Five Food Substances. 

 /. 1511:143-192. Nutrition. 



g. 1708 : 410-411. Food of Man. 



192. DIGESTION 



When we eat food, it may or may not do us good, according 

 to our ability to digest and to absorb the useful parts of it. 

 Digestion and absorption are entirely different. Absorption 

 is the taking up, by the blood, from the walls of the stomach 

 and intestines, the food material which can be used by the 

 system. Digestion is merely the rendering soluble of the en- 

 tire mass of food which is taken into the stomach ; that is, the 

 food must be turned into a more or less liquid condition. 



The stomach supplies the gastric juice, which contains .2 

 per cent of an acid called hydrochloric, and two ferments called 



