906 METABOLISM. 



kept alive with boiled meat and polished rice. They emaciate quickly 

 and rapidly recover again if they receive oryzanine. 



It follows from the above that there exists a certain unexplainable 

 contradiction between the important observations of STEPP and those 

 of the other investigators on the one side and the very interesting, prolonged 

 experiments of OSBOKNE and MENDEL with pure foodstuffs on the 

 other side. 



IH. METABOLISM WITH VARIOUS FOODS. 



For carnivora, as above stated,, meat as poor as possible in fat may 

 be a complete and sufficient food. As the proteins moreover take a special 

 place among the organic nutritive bodies by the quantity of nitrogen they 

 contain, it is proper that we first describe the metabolism with an exclu- 

 sively meat diet. 



Metabolism with food rich in proteins, i.e., feeding only with meat as 

 poor in fat as possible. 



By an increased supply of proteins the catabolism and the elimination 

 of nitrogen is increased, and this in proportion to the supply of proteins. 



If a certain quantity of meat has daily been given to carnivora as 

 food and the quantity is suddenly increased, an augmented catabolism 

 of proteins, or an increase in the quantity of nitrogen eliminated, is the 

 result. If the animal is daily fed for a certain time with larger quantities 

 of the same meat, a part of the proteins accumulates in the body, but 

 this part decreases from day to day, while there is a corresponding daily 

 increase in the elimination of nitrogen. In this way a nitrogenous 

 equilibrium is established; that is, the total quantity of nitrogen eliminated 

 is equal to the quantity of nitrogen in the absorbed proteins or meat. 

 If, on the contrary, an animal in nitrogenous equilibrium, having been 

 fed on large quantities of meat, is suddenly given a small quantity 

 of meat per day, it uses up its own body proteins, the amount de- 

 creasing from day to day. The elimination of nitrogen and the catab- 

 olism of proteins decrease constantly, and the animal may in this case, 

 also pass into nitrogenous equilibrium, or almost into this condition 

 These relations are illustrated by the following table (VOIT) : l 



Grama of Meat in the Food per Day. 



1 Hermann's Handbuch, 6, Part I, 110. 



