FOOD AND DIGESTION 



lO/ 



tube, the absorption beginning even in the mouth. What 

 reasons can you give for the absorption of food being 

 many times greater in the small intestine than in the 

 stomach ? Through what large tube is the fat carried in 

 passing from the lacteals to the 

 veins ? Into what large vein do all 

 the capillaries that take part in ab- 

 sorption empty ? (Colored Fig. 5.) 

 What is the provision for storing 

 the sugar so that it will not pass 

 suddenly into the blood after a 

 meal, but may be given to the blood 

 gradually ? Food is assimilated, or 

 changed into living matter (proto- 

 plasm), in the cells. Blood and 

 lymph (except the white corpuscles) 

 are not living matter. (Fig. 100.) 



FIG. ioo. THE Two 

 PATHS OF FOOD ABSORP- 

 TION. Thoracic duct (for 

 fats) ; through the portal 

 vein and liver (for all 

 other foods) . 



THOUGHT QUESTIONS. The Digestive 

 Organs. 1. In which of the digestive 

 organs is only one kind of secretion fur- 

 nished by glands? 2. In which organ 

 are three kinds of secretions furnished by 

 glands? 3. Which class of food goes 



through the lymphatics ? 4. Which classes of foods go through the 

 liver ? 5. Which classes of foods are digested in only one organ ? 

 6. Which classes of foods are digested in two organs ? 7. Which 

 division of the food tube is longest ? Broadest ? Least active ? 

 Most active ? 8. Soup is absorbed quickly ; why does eating it at 

 the beginning of a meal tend to prevent overeating? 



Hygienic Habits of Eating. In hot weather much 

 blood goes to the skin and little to the food tube, and di- 

 gestion is less vigorous. Hearty eaters suffer from heat 

 in summer because of much fuel, and because the blood is 

 kept away from the skin where it would become cool and 

 then cool the whole body. Some persons believe that the 



