304 PHYSIOLOGY OF ALIMENTATION. 



or total excision with transplantation of a portion of the 

 organ to some other part of the body. These various pro- 

 cedures have been adopted by different investigators. The 

 results obtained vary greatly. All seem to agree, however, 

 that the digestion and absorption of proteins are interfered 

 with markedly when the pancreatic juice no longer pours 

 into the duodenum. This is not surprising when it is remem- 

 bered how well protein digestion may go on after removal 

 of the stomach. Generally speaking, less than half the pro- 

 tein of an ordinary meal is digested when the pancreas is 

 gone. HARLEY found only 18 percent digested after removal 

 of the pancreas, though DEUCHER found 80 percent utilized 

 after complete occlusion of the pancreatic duct. 1 The pro- 

 teolytic activity must evidently be sought in these cases in 

 the secretion of the stomach, augmented by those found in 

 the secretions and mucous membrane of the small intestine. 

 I What, now, is the fate of the protein which disappears 

 from the lumen of the alimentary tract? Of fundamental 

 importance is the fact that even after a meal rich in proteins 

 neither peptones nor proteoses appear in either the blood or 

 the lymph. This has been shown to be true in various ways : 

 Direct analysis of the blood leaving the intestine points in 

 this direction. Furthermore, peptones injected directly into 

 the blood are excreted through the kidneys, and normally 

 no peptones can be found in the urine, even after a very 

 heavy protein meal. The peptones lower the blood pressure 

 when injected into the general circulation, yet a lowered 

 blood pressure is never observed after the consumption of 

 large amounts of protein, or even after the introduction of 

 large amounts of peptone into the alimentary tract. All this 

 indicates clearly that peptones do not get into the blood or 

 lymph (at least in sufficient amounts to be recognized by 

 the analytical means ordinarily employed). Nor do peptones 

 and proteoses in the blood issuing immediately from the in- 



I.e., p. 316. 



