PROTEIN SYNTHESIS. 507 



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 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 w r e can also add that according to the investigations of FREUND 

 and v. KOROSY l the blood coming from the intestine during digestion 

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

 tein 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 decomposed 

 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 rel'a- 

 tively greater quantity of coagulable protein should occur in the rnucosa 

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

 PRINGLE and CRAMER, by a method * which requires confirmation, 

 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 intes- 

 tine, are richer in non-coagulable protein than the starving animal, a 

 condition which is related to the role of the leucocytes in the protein 

 assimilation. This question of the absorption of proteins in the intes- 

 tine is still unexplained in many directions. 



The extent of the protein absorption is dependent essentially upon the 

 kind of food introduced, since as a rule the protein substances from an 

 animal source are much more completely absorbed than from a vege- 

 table source. As proof of this the following observations are given: 

 In his experiments on the utilization of certain foods in the intestinal 

 canal of man RUBNER found that with an exclusively animal diet, on 

 partaking of an average of 738-884 grams of fried meat or 948 grams 

 of eggs per day, the nitrogen deficit with the excrement was only 2.5-2.8 

 per cent of the total nitrogen introduced. With a strictly milk diet 

 the results were somewhat unfavorable, since after partaking of 4100 

 grams of milk the nitrogen deficit increased to 12 per cent. The condi- 

 tions are quite different with vegetable food, as shown by the researches 

 of MEYER, RUBNER, HULTGREN and LANDERGREN, who made experi- 

 ments with various kinds of rye bread and found that the loss of nitro- 



1 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, Jounu 

 of Physiol., 37. 



