460 PHYSIOLOGICAL CHEMISTRY. 



contains no proteids besides peptones may not only preserve its 

 nitrogenous equilibrium, but indeed its proteid condition may in- 

 crease. In opposition to this VOIT believes, basing his^opinion upon 

 some recent experiments conducted by FEDER, that the peptones are 

 completely destroyed in the body; that indeed by their ability of 

 sparing the proteids they entirely, or almost entirely, prevent the 

 consumption of proteids, but cannot pass into proteid. The gen- 

 eral view is still that (see page 231) peptones are reconverted into 

 proteids in the body. 



In the above-mentioned experiments with peptones a mixture of 

 albumoses and peptones in the modern sense was used. Recently 

 ZUNTZ and POLLITZER have made experiments on dogs partly with 

 meat and partly with pure peptones and albumoses of various kinds. 

 In these experiments a deposit of proteids (retention of a part of 

 the nitrogen) seems to have taken place in the body, and if a cor- 

 rection be made for that nitrogen which is contained in the extrac- 

 tive bodies of the meat, then the investigated digestive products 

 seem to have about the same nutritive value for the body as the 

 corresponding quantity of proteids of the meat. 



From experiments made by WEISKE on herbivora it appears 

 that asparagin may spare albumin in such animals. In carnivora 

 (J. MUNK) and in mice (VoiT and POLITIS) it was found that 

 asparagin does not seem to have any sparing action on the proteids. 

 It is not known how it acts in man. 



Exchange of Material on a Diet consisting of Proteid and Fat. 

 Fat cannot arrest or prevent the destruction of proteids; but it can 

 decrease it, and so spare the proteids. This is apparent from the 

 following table of VOIT. A is the average for three days, and B for 

 six days. 



TABLE VII. 



Food. Flesh. 



Meat. Fat. Metabolized. On the Body. 



A.... 1500 1512 - 12 



B. . . . 1500 150 1474 + 26 



The adipose tissue of the body acts like the food-fat, and the 

 proteid-sparing eifect of the former may be added to that of the 

 latter, so that a body rich in fat may not only remain in nitrogenous 



