INORGANIC NUTRIENTS 161 



The salts of iron have not as yet been discussed. The newborn animal 

 possesses a greater supply of these than mature animals and can draw 

 upon this excess for some time. Milk, compared with other feeding stuffs, 

 is decidedly poor in iron. 



The proportion in which CaO, MgO, KoO and NagO occur is an impor- 

 tant matter, as well as the proportion of the total chemical bases to the 

 mineral acids. There should be an excess of the bases. An excess of 

 acids would neutralize the bases of the skeleton and tend to dissolve the 

 latter, that is, produce halisteresis and rachitis. With respect to acid 

 excess, it should be noted that in the process of albumen combustion the 

 oxidation of the sulphur produces sulphuric acid. In herbivora the pres- 

 ence of hippuric acid causes a further loss of the alkalies or bases. Since 

 crude fiber constitutes the raw material from which hippuric acid is pro- 

 duced, grasses rich in this material (grasses of poor quality) have a 

 tendency to deplete the supply of lime in the body. A marked excess of 

 one salt as compared with the others required may disturb metabolism 

 and under certain circumstances produce an actual deficiency of such 

 other salts, even when the latter are taken up in normally required 

 amounts. The magnesia content should not exceed that of lime in the 

 ration, but should rather be in the proportion of 1 to 1.7 as compared 

 with lime (the proportion in which these two salts occur in the blood). 



gm. lime gm. magnesia 



1 leg. of wheat bran contains 1.4 7.0 



1 kg. of linseed cake contains 4.3 8.1 



1 kg. of rice feed meal contains 1.2 9.5 



1 kg. of Indian corn contains 0.3 2.0 



1 kg. of potatoes contains 0.3 0.6 



1 kg. of stock beets contains 0.3 0.4 



1 kg. of rye flour contains 0.2 1.4 



In contrast to the above, 



1 kg. of meadow hay contains 9.5 4.1 



1 kg. of red clover hay contains 20.1 6.3 



1 kg. of oat straw contains 3.8 1.2 



1 kg. of cow's milk contains 1.7 0.2 



1 kg. of meat contains 0.3 0.3 



4. Testing Feed Utilization and Assimilation 



In all feeding thorough digestion and complete utilization should be 

 the objects constantly kept in mind, so that the end attained will justify 

 the outlay. Examination of the feces will inform us in regard to the 

 degree of digestion and absorption. The degree of utilization of the 

 nutrients would be determined in an exact manner by chemical analysis. 

 Here inspection of the feces would give some information along this 

 Hne, though by no means always entirely satisfactory even for practical 

 purposes. The presence of undigested grains should be noted (pressure 

 exerted upon such grains forces out the soft interior, distinguishing them 

 from empty skins or hulls!). Undigested particles of potatoes or other 

 food fragments are significant. The microscope will be an aid in recog- 



