METABOLISM WITH FOOD RICH IN PROTEINS. 909 



proteins, are ordinarily catabolized to only a small extent, about 1 per 

 cent daily (Vorr). By an increased supply of proteins the activity of 

 the cells and their ability to decompose nutritive proteins is also increased 

 to a certain degree. When nitrogenous equilibrium is obtained after 

 an increased supply of proteins, it indicates that the decomposing power 

 of the cells for proteins has increased so that the same quantity of proteins 

 is metabolized as is supplied to the body. If the protein metabolism is 

 decreased by the simultaneous administration of other non-nitrogenous 

 foods (see below), a part of the circulating proteins may have time to 

 become fixed and organized by the tissues, and in this way the mass of 

 the flesh of the body increases. During starvation or with a lack of pro- 

 teins in the food the reverse takes place, for a part of the tissue proteins 

 is converted into circulating proteins which are metabolized, and in this 

 case the flesh of the body decreases. 



VOIT'S theory has been criticised by several investigators and espe- 

 cially by PFLUGER. PFLUGER'S belief, based on an investigation made 

 by one of his pupils, SCHONDORFF/ is that the extent of protein destruc- 

 tion is not dependent upon the quantity of circulating proteins, but 

 upon the nutritive condition of the cells for the time being a view 

 which does not widely differ from VOIT if the author does not misunder- 

 stand PFLUGER. VoiT 2 has, as is known, stated that the conditions for 

 the destruction of substances in the body exist in the cells, and also that 

 the circulating protein is first catabolized after having bean taken up 

 by the cells from the fluids washing them. Besides this, certain inves- 

 tigations conclusively show that the extent of protein catabolism is depend- 

 ent upon the concentration of the decomposable proteins at the place 

 where the decomposition is taking place. Thus in confirmation with 

 the earlier investigations of v. GEBHARDT and KRUMMACHER, THOMAS, 

 v. HOESSLIN and LESSER 3 have recently shown that on feeding with 

 a certain quantity of protein, less protein was catabolized when the pro- 

 tein was supplied piecemeal, i.e., in several small portions during the day 

 instead of at one time. That the peculiarity of the nitrogen elimination 

 in starvation arid after sufficient protein supply depends essentially 

 upon the concentration of the decomposable proteins (or more correctly the 

 decomposable nitrogenous substances) is no doubt also generally admitted. 4 



1 Pfliiger, Pfluger's Arch., 54; Schondorff, ibid., 54. 



2 Zeitschr. f. Biologic, 11. 



3 K. Thomas. Arch. f. (Anat. u.) Physiol., 1909; H. v. Hoesslin and E. J. Lesser, 

 Zeitschr. f. physiol. Chem., 73, when also the works of v. Gebhardt and Kummacher are 

 cited. 



4 See also E. Voit and A. Korkunoff, Zeitschr. f. Biol., 32, and O. Frank and R. 

 Trommsdorff, ibid., 43. 



