182 



NUTRITION OF FARM ANIMALS 



and for other purposes in the body. Both questions, however, 

 may be regarded as settled in the affirmative. The matter is 

 of importance in its relations to the use of iron in medicine but 

 is of no special significance in stock feeding. 



The excretion of iron takes place almost exclusively through 

 the intestines and this fact led to the earlier conclusion that 

 inorganic iron cannot be resorbed. 



8. FUNCTIONS or THE NUTRIENTS 



262. General scheme of metabolism. In considering the 

 metabolism of the several classes of nutrients in the foregoing 

 paragraphs, it was found that the main features of the process 



FIG. 23. Diagrammatic scheme of metabolism. 



in each case might be conceived of in accordance with the ideas 

 suggested in 2 (210-212) as consisting of a complex of rever- 

 sible reactions accelerated or retarded by intracellular enzyms. 

 By combining the equations used to represent those reactions, it 

 appears possible to take a further step and formulate the fol- 

 lowing highly generalized scheme for the total metabolism which 

 may serve to show the interrelations between the metabolism 



