166 THE HUMAN BODY. 



digestion strengthens the stomach up to the point of being 

 able to do its own work. 



Enough has probably been said to show that dyspepsia 

 is not a disease, but a symptom accompanying many 

 diseased conditions, requiring special knowledge for their 

 treatment. From its nature depriving the body of its 

 proper nourishment it tends to intensify itself, and so 

 should never be neglected ; a stitch in time saves nine. 



Absorption from the Alimentary Canal. Through its 

 whole extent the mucous membrane lining the digestive 

 tube is traversed by very closely packed tubes of two 

 kinds, the blood and lymph vessels. Matters ready for 

 absorption pass through or between the cells covering the 

 surface of the mucous membrane, and then through the 

 very thin walls of the smallest blood and lymph vessels ; 

 and by these vessels are conveyed to larger channels with 

 thicker walls, which all ultimately lead to the heart. From 

 the heart the digested and absorbed food is distributed to 

 every organ of the body, 



Absorption from the Mouth, Pharynx, and Gullet is but 

 slight. Some water, some common salt, some sugar, and 

 some grape sugar (made from starch by the action of saliva) 

 are no doubt taken up during the processes of chewing and 

 swallowing. But the time which elapses between taking a 

 mouthful of food and its transference to the stomach is 

 usually too short to allow the occurrence of any consid- 

 erable absorption. 



Why should dyspepsia never be neglected? 



What tubes are found in the mucous membrane of the alimentary 

 canal? How do dissolved foods enter them? Where are the ab- 

 sorbed matters carried? To what parts are they finally distributed? 



What foodstuffs are partly absorbed in mouth, pharynx, and 

 gullet? Why does not any great amount of absorption take place 

 in those parts? 



