286 PHYSIOLOGY OF ALIMENTATION. 



period, it is found that starch is also most rapidly absorbed 

 during this period. 



After what has been said it becomes somewhat difficult 

 to explain the fate of starches which under experimental 

 conditions may be fed an animal in which the salivary and 

 pancreatic secretions are lacking, or patients in whom these 

 are insufficient in amount or poor in the proper enzymes. 

 It has been found that in dogs in which the pancreatic ducts 

 have been ligated that upwards of 50 percent of the starches 

 fed cannot be recovered from the faeces. By what agencies 

 these starches are rendered absorbable is not known, for the 

 action of the gastric acid, the bacteria of the alimentary tract, 

 and the slight amylolytic activity attributed by some to the 

 intestinal juice seem insufficient. 1 



The question of the channels through which the carbo- 

 hydrates are distributed to the body after passing through 

 the epithelium of the alimentary tract seems to be settled 

 beyond question, v. MERING showed in 1877 that the absorbed 

 carbohydrates pass through the portal vein to the liver, for 

 while under normal conditions the blood of this vessel con- 

 tains no more than about 0.2 percent dextrose, it may 

 contain twice this amount after a carbohydrate meal. De- 

 terminations of the sugar content of the lymph obtained from 

 the thoracic duct showed that this fluid contained, both before 

 and after a meal of carbohydrates, a fairly constant percent 

 (less than 0.2 percent) of sugar. This shows that under 

 ordinary circumstances all the carbohydrates of the food 

 leave the alimentary tract by way of the blood. When, 

 however, excessive amounts of carbohydrates are fed a 

 small portion of them may pass over into the lymph-chan- 

 nels, as shown by GINSBERG'S observations on rabbits and 

 dogs. MUNK and ROSENSTEIN'S studies on a case of lymphatic 

 fistula in a human being fully confirm these observations. 

 It was found in this case, in which practically all the lymph 



1 See MUNK: Ergebnisse d. Physiol., 1902, 1, Ite Abth., p. 308. 



