lilAlTUAL OF OATTLE-FEEBING. 125 



If we assume 12 grammes of m-ea as the amoimt due to 

 tlie coiibtaut factor, and subtract tliis from the total excre- 

 tion on the several days in these experiments, the remain- 

 ders will exliibit the action of the variable factor. In the 

 table on the opposite page this has been done. 



This table shows still more clearly the great injfluenee of 

 the variable factor at first and its speedy disappearance 

 when the supply of food is cut off. 



Organized and Circulatory Protein. — It is evident 

 from these and a great number of similar results that tlie 

 protein of the living body exists in two f orais— a compara- 

 tively stable one, which decomposes slowly and yielded in 

 these experiments about 12 grammes of urea per day, and 

 an easily decomposable one, whose amount depends on the 

 food ajid which is rapidly destroyed when food is with- 

 held- The quantity of the latter is small as compai^ed 

 with that of the f onner. In experiment 11, for example, 

 where its amount was greatest, its total quantity was only 

 about 3,364: grammes of flesh (2M.3 grms. of urea x 13,77), 

 while the animal weighed about 35,000 grammes. 

 '^ Voit designates the stable protein of the body as organ- 

 ised proteifhy and considers that it makes up the mass of 

 the organs; while the variable and easily decomposing 

 quantity he calls eitmdatary jyrotdm.. Under the latter he 

 does not include the protein of the blood and lymph,, but 

 only the dissolved protein which penetrates from these 

 into the tissues and bathes the cells in a nourishing fluid. 



Some good authorities dispute the correctness of the 

 names circulatory and organized protein, but there is no 

 dispute as to the correctness and importance of the distinc- 

 tion which they imply between the two forms of protein 

 in the body. For our present purpose this is the impor- 

 tant thing, and we shall use Voit's nomenclature, mider- 



