92 APPLIED PHYSIOLOGY 



126. Assimilation of glucose. Glucose enters the blood 

 in the villi, and is carried from there to the liver by means 

 of a large vein called the portal vein. As the blood 

 emerges from the liver, it contains almost uniformly -^fa 

 part of glucose, no matter what amount of sugar is in the 

 portal vein. The liver contains a sugarlike substance 

 called glycogen, which increases in amount after digestion, 

 and almost disappears a few hours after eating. So it is 

 thought that glucose is stored in the liver as glycogen, and 

 given up to the blood in a steady stream. 



In the blood the glucose is all oxidized to carbonic acid 

 gas and water, giving out heat and energy. One ounce of 

 glucose requires about one and one fifth ounces of oxygen 

 to oxidize it completely. 



127. Assimilation of peptone. Peptone is a poison to 

 the body and must be changed immediately after entering 

 the circulation. It is carried directly to the liver by the 

 portal vein, and there all becomes changed back to forms 

 of albumin which will not diffuse through a blood tube, 

 except under pressure. The liver further makes the albu- 

 min a living part of the blood. Some albumin is oxidized 

 in the liver, but a large part is carried to the cells of the 

 body. Each cell in the body is thus bathed in albuminous 

 food brought to it by the blood. 



Like an ameba, each cell chooses as much of the albu- 

 min as it needs for food, and, taking it in by any part of 

 the surface of its body, makes it a living part of itself. 

 Finally, even the living albumin of the cell is oxidized, an 

 ounce requiring one and one half ounces of oxygen. 



128. Absorbed poisons thrown out by the liver. Fermen- 

 tation in the intestine produces injurious substances, and 

 the bile brings in waste matter. Decayed food, too, con- 

 tains poisons. All these substances may be absorbed and 



