i o8 THE PHYSIOLOGY OF PROTEIN METABOLISM 



investigation of the intracellular or other ferments found in the plasma. 

 They demonstrated that when the occasion arises the organism can 

 secrete into the plasma a ferment or ferments to deal with products 

 which are not normally present in this fluid. A long series of 

 observations were made after the subcutaneous or intravenous injection 

 of various proteins. It was invariably found that a ferment was 

 formed, which was not specific, however, for any definite type of pro- 

 tein. Moreover, if the protein, for example, raw egg albumin, were 

 taken in large amount by the mouth, the part, which, as already 

 mentioned (see p. 12), was absorbed unchanged, generated a specific 

 ferment in the plasma. As the normal plasma does not contain any 

 proteolytic ferment the amount of protein absorbed in an unchanged 

 form must be, under normal conditions, remarkably small. 



