ABSORPTION BY BLOOD-VESSELS. 4-21 



solved by the gastric juice and converted into albuminose, is 

 taken up directly by the blood-vessels of the stomach. It 

 may, indeed, be assumed as a general law, that digested mat- 

 ters are in great part absorbed as soon as their transforma- 

 tions in the alimentary canal have been completed. 



In the passage of the food down the intestinal canal, as 

 we have already seen, there is a constant loss of material. 

 As the digestion of the albuminoids is completed, these prin- 

 ciples are absorbed, and their passage into the mass of blood 

 is indicated chiefly by an increase in its proportion of al- 

 bumen. Analyses by Beclard of blood taken from the portal 

 veins during digestion have shown a great increase in the pro- 

 portion of fibrin over the blood in other parts of the venous 

 system and in the same vessel during the intervals of diges- 

 tion. 1 These observations have been repeatedly confirmed, and 

 many of the other products of digestion, such as glucose and 

 fatty emulsion, have also been demonstrated in quantity in the 

 blood of the portal vein during absorption. The fats, though 

 taken up in greatest part by the lacteals, are always found in 

 greater or less quantity in the portal blood. It has fre- 

 quently been observed that after a full meal consisting 

 largely of fat, the blood from the portal vein, as it cools and 

 coagulates, leaves a white scum of fat upon the surface. 2 On 

 one occasion we observed in the portal blood of an animal 

 killed in full digestion a layer of fat on cooling so thick that 

 a quantity of blood, which was spilled upon a table and the 



different animals show that in the earnivora, and in most animals with a single 

 stomach, this takes place with great rapidity. In the horse, the mucous mem- 

 brane of a great portion of the stomach is lined by pavement epithelium like that 

 found in the oesophagus, and absorption from the stomach is very slow. (COLIN, 

 Traite de Physiologic Comparie, Paris, 1856, tome ii., p. 29 et seq. 



1 BECLARD, Recherches Experimentales sur les Fondions de la Rate etsur celles 

 de la Vcine Porte. Archives Generates de Medecine, Paris, 1848, p. 443. 



2 Bernard found in the dog that the portal blood sometimes contained almost 

 as much fatty emulsion as the chyle (Du Role de VAppareil Chyli/ere dans I* Ab- 

 sorption des Substances Alimentaires}. Comptes Rendus, Paris, 1850, tome xxxi., 

 p. 802. 



