PROTEIN METABOLISM 85 



able to prove an increase. Kutscher and Seemann (I.e.) were 

 unable, in their experiments, to find the crystalline products 

 which they isolated from the contents of the intestine during 

 digestion, either in the intestinal wall or in the blood. They 

 discovered, however, in the wall of the intestine biuret-free 

 extractive bodies which, on treatment with boiling acids, yielded 

 leucin. They drew the conclusion from this observation that 

 the leucin (and probably other crystalline products) absorbed 

 from the canal is linked up with some other substance or 

 substances into bodies of a more complex nature in the intestinal 

 wall. Embden and Knoop (I.e.) were quite unable to prove 

 that any synthetic action ever took place in the walls of the 

 small intestine, when working, at any rate, with surviving gut 

 outside the body. This is quite the reverse of what Glaessner l 

 claimed to have found in the case of the gastric mucous mem- 

 brane. This worker stated that, as Hofmeister 2 had previously 

 found, if the albumoses present at the time of digestion be 

 allowed to remain in contact with the isolated mucous mem- 

 brane of the stomach, they for the most part disappear as 

 such, and that in their place appears a coagulable protein 

 body. Concerning the nature of this protein Glaessner says 

 nothing, but holds its formation to prove that by the altera- 

 tion of the albumose a synthesis has taken place. Objections 

 have been raised to this work, and Cohnheim has held that 

 the results noted by Glaessner may be due to differences in 

 the case of coagulability of absolutely fresh protein of the 

 mucous membrane, and of that which has been out of the 

 body for some little time. Salaskin 3 offered as an explanation 

 that the increase of protein may simply be due to a normal 

 restitution of the cell protoplasm after its activity in ferment 

 production. 



Reference may be here made to a change which has been 

 declared by some to be a true resynthesis — namely, to the for- 

 mation of anhydride albumen, or plastem as it has been called. 

 The curious property possessed by rennin of producing a 

 precipitate — the plastei'n — in solutions of albumoses or pep- 

 tones was first brought to notice by Okunew 4 in a Russian 



1 Glaessner, Hofmeister's Beitrage, I, 1901, 320. 



2 Hofmeister, Schmiedeberg's Archiv, 19, 1885, 1. 

 s Salaskin, Zeit. f. physiol. Chem. 35, 1902, 419. 



4 Okunew (quoted by Sawjalovv, Pfiiiger's Archiv, 85, 1901, 171). 



