562 TISSUES OF THE CONNECTIVE SUBSTANCE. 



tions, which were continued for a series of years, were subject to such 

 great defects that they are not conclusive as to the formation of fat 

 from proteins. He especially emphasizes the fact that these investigators 

 started from a wrong assumption as to the elementary composition of 

 the meat, and that the quantity of nitrogen assumed by them was too 

 low and the quantity of carbon too high. The relation of nitrogen to 

 carbon in meat poor in fat was assumed by VOIT to be as 1:3.68, while 

 according to PFLUGER it is 1:3.22 for fat-free meat after deducting the 

 glycogen, and according to RUBNER 1:3.28 without deducting the gly- 

 cogen. On recalculation of the figures, using these coefficients, PFLUGER 

 has arrived at the conclusion that the assumption as to the formation 

 of fat from proteins finds no support in these experiments. 



In opposition to these objections, E. VOIT and M. CREMER have made 

 new feeding experiments, to show the formation of fat from proteins, 

 but the proof of these recent investigations has been disputed by PFLUGER. 

 On feeding a dog on meat poor in fat (containing a known quantity of 

 ether extractives, glycogen, nitrogen, water, and ash), KUMAGAWA 1 

 could not prove the formation of fat from protein. According to him 

 the animal body under normal conditions has not the power of forming 

 fat from protein. 



Several French investigators, especially CHAUVEAU, GAUTIER, and 

 KAUFMANN, 2 consider the formation of fat from proteins as positively 

 proved. KAUFMANN has recently substantiated this view by a method 

 which will be spoken of in detail in Chapter XVII, in which he studied 

 the nitrogen elimination and the respiratory gas exchange in conjunction 

 with the simultaneous formation of heat. 



As we are agreed that carbohydrates and glycogen, as well as sugar, 

 can be formed from proteins, the fact cannot be denied that possibly 

 an indirect formation of fat from proteins, with a carbohydrate as an 

 intermediate step, can take place. The possibility of a direct fat for- 

 mation from proteins without the carbohydrate as intermediary must 

 also be generally admitted, although such a formation has not been 

 conclusively proved. 



According to CHAUVEAU and KAUFMANN, in the direct formation of 

 fat from proteins, the fat is formed besides urea, carbon dioxide, and 

 water, as an intermediary product in the oxidation of the proteins, while 

 GAUTIER considers the formation of fat from proteins as a cleavage 

 without the taking up of oxygen. If fat is formed from protein in the 

 animal body, then such formation is not a splitting off of fat from the 



1 See Rosenfeld, Fettbildung, Ergebnisse der Physiologic, 1, Abt. 1. 

 2 Kaufmann, Arch, de physiol., (5) 8, where the works of Chauveau and Gautier 

 are cited. 



