WHEEE NUTBIBNTS ARE ABSOKBED 



141 



Fig. 48 — Diagram of absorption, showing 

 how food reaches the blood circulation. 



teals is all in the form of an emulsion.. It is the milky- 

 character of this emulsion which accounts for the appear- 

 ance and name of this branch of the lymphatics. The 

 seat of absorption of fats is the villi of the small intestine, 

 and the lacteals, which receive it finally, put it into the 

 blood circulation at the 

 opening of the thoracic -^^''^ 



duct into the left jugular 

 vein. (See Fig. 48.) 



Water and salts. These 

 nutrients are absorbed 

 directly into the blood 

 mainly in the small and 

 large intestine. The 

 salts and the water pass 

 through by osmosis owing 



to the osmotic pressure of salts contained in the blood. 

 In the case of water, the long time required by the food 

 to pass through the large intestine permits the great 

 bulk of water to become absorbed in this tract. This 

 is further evidenced by the fact that while the chyle 

 which enters the large intestine is very thin and watery, 

 the matter that is passed out of the rectum is mainly 

 solid. Very little water or salt is absorbed in the 

 stomach; 



Alcohol. Alcohol is very quickly and completely absorbed 

 by the blood vessels of the stomach, very little ever pass- 

 ing into the intestine. This rapid absorption in the 

 stomach accounts for the quick effect of this substance 

 upon the body. It also has its beneficial side in that, 

 as ,a solvent of certain drugs, it enables them to be put 

 into circulation quickly. 



