ABSORPTION FROM THE ALIMENTARY CANAL 127 



capillaries which are concerned in this absorption occupy the 

 villi, and are called lacteals. 



(A) From the Stomach. Since all classes of food except fats 

 have been partly digested in the stomach, it follows that all 

 except fats may be absorbed here. However, as a matter of 

 observation, the stomach is of much less importance in absorp- 

 tion than was once thought. Practically, it is found that water 

 and salts are passed quickly on toward the duodenum and are 

 not largely absorbed in the stomach. Sugar and peptones are 

 also found to be absorbed rather sparingly here. All these 

 substances can undoubtedly be absorbed by the gastric mucous 

 membrane, and their complete absorption is prevented only by 

 their removal through the pylorus. It is interesting to note that 

 alcohol and condiments, like pepper and mustard, greatly 

 hasten absorption, either by increasing the blood flow or by 

 directly stimulating the " vital activity" of the epithelium. 



(B) From the Small Intestine. Here absorption of all classes 

 of food is possible, and here in fact most of the foods are ab- 

 sorbed. The digestive influences are more active upon all the 

 aliments, the mucous membrane is well adapted to absorption 

 by reason of its valvulae conniventes and its villi, and the food 

 necessarily remains in the small intestine for a consideraole time. 

 The fats are absorbed in the upper part of the small intestine; 

 for they pass into the lacteals of the villi, and these do not exist 

 in the lower ileum. The fluids swallowed are almost com- 

 pletely absorbed here, but their place is taken by the intestinal 

 secretions. The proteids are absorbed to the extent of 85 per 

 cent., more or less, before reaching the large intestine, and the 

 carbohydrates almost entirely disappear. 



(C) From the Large Intestines. The absorption process in 

 the large intestine is quite active. The passage of the mass 

 through it is slower, and even occupies an absolutely greater 

 time than the journey through the much longer small intestine. 

 The consistence of the contents progressively increases owing to 



