530 DIGESTION. 



the other hand it is not possible to deny the importance of the liver for 

 the protein syntheses. As EMBDEN and his collaborators have shown on 

 perfusing the liver containing a large amount of glycogen, that d-alanine 

 was formed and EMBDEN explains this formation by a destruction of 

 glucose or lactic acid and pyroracemic acid. With experiments with 

 blood perfusion of the liver, a-amino-acids are formed from the am- 

 monium salts of the corresponding a-keto-acids. The combination 

 NH 4 .O.CO.CO.R passes into HO.CO.CH(NH 2 ).R. The cleavage 

 products of the carbohydrates can be converted in the liver into char- 

 acteristic constituents of the protein molecule. 1 In this connection 

 we must here mention the experiments of LUTHJE 2 in which he found 

 a nitrogen retention after feeding only one amino-acid with abundance 

 of carbohydrate. 



What kind of protein is formed in the synthesis? This we do not 

 know. ABDERHALDEN'S belief is that it is plasma protein, which, as 

 is well known, is the same in each animal independent of the kind of 

 protein introduced with the food and from which the cells of the body 

 then create the further protein material. Objections can be raised 

 against this hypothesis, but still it is worth consideration. In favor 

 of this we can also add that according to the investigations of FREUND 

 and v. KoROSY 3 the blood coming from the intestine during digestion 

 is richer in coagulable protein than other blood, and also that this 

 protein, FREUND asserts, belongs to the globulin group. This globulin, 

 according to FREUND and TOEPFER, is not identical with the ordinary 

 serglobulin mixture, but is a pseudoglobulin formed in the intestine 

 from the food protein by synthesis, and which is more easily decom- 

 posed or further utilized in the liver and other organs. Further research 

 in this direction is necessary, as we have other investigations which 

 are essentially different. If a re-formation of coagulable proteins takes 

 place from amino-acids during digestion, it is to be expected that a 

 relatively greater quantity of coagulable protein should occur hi the 

 mucosa of the digesting intestine as compared with the non-digesting 

 intestine. PRINGLE and CRAMER, by a method which requires con- 

 firmation, claim that in the digesting animal (cat), the blood, and to a 

 still higher degree the intestinal mucosa, and especially the lymph nodes 

 of the intestine, are richer in non-coagulable protein than the starving 

 animal, a condition which is related to the r61e of the leucocytes in the 



Zeitschr. 29, 423 (1910); 38, 393, 407, 414 (1911); 45, 1-207 (1912); 

 summary, 45, 201. 



2 Pfliiger's Arch. 113, 547 (1906). 



3 v. Korosy, Zeitschr. f. physiol. Chem., 57; Freund, Zeitschr. f. exp. Path. u. 

 Therap., 4; G. Toepfer and Freund, and Toepfer, ibid., 3; Pringle and Cramer, Joura, 

 of Physiol., 37. 



