CHAPTER II. 

 PROTEIN REGENERATION. 



How and in what form is protein normally conveyed from the intestine 

 to the tissues ? It has been shown that it can be absorbed in a natural 

 undigested condition (pp. 1 2, 1 3), and it has also been shown (p. 1 5) that 

 protein which reaches the blood stream through other channels than 

 passage through the intestinal mucous membrane can be dealt with 

 probably through the agency of a special enzyme. But on the other 

 hand entrance of protein by these channels cannot be considered the 

 normal one. 



Are|Proteoses or Peptones Found in the Blood? 



A certain number of modern workers still adhere to the old belief 

 that the absorption takes place in the form of proteose or peptone, 

 but, as has already been shown, the work of Cohnheim has rendered 

 this extremely unlikely. In support of their contention, however, 

 they make the statement that proteoses or peptones can be detected 

 in the blood stream, particularly the portal stream, during digestion. 

 Much contradictory evidence has been put forward with regard to this 

 statement. After the work of Neumeister (305) it was generally be- 

 lieved, that no proteose or peptone could be detected in the blood, but 

 in 1903 Embden and Knoop (117), as the result of their experiments 

 on the fate of proteoses and peptones when brought into contact with 

 the intestinal mucous membrane, stated that, if the tests were carefully 

 enough carried out, these substances could be detected in the blood. 

 They held that such absorption must take place, as they claim to have 

 demonstrated that peptone is neither synthetized to a higher product 

 a coagulable protein nor broken down to an abiuret product when 

 brought into contact with the intestinal mucous membrane ; they could 

 not, however, always demonstrate the presence of this non-coagulable 

 biuret-giving substance in the blood. Langstein (239) confirmed the 



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