INORGANIC ELEMENTS OF FOOD. 411 



sary dose of inorganic principles, which must he assimilated daily, 

 and which is quite indispensable to maintain them in health and 

 vigor. 



It is easy to arrive at a knowledge of the mineral principles which 

 are necessary as elements of the diet, by ascertaining their quantity 

 in the ration, which long experience has shown to be sufficient. Yet 

 as there is reason to believe that in many cases mineral substances 

 are present in excess, I have thought that it might be useful to de- 

 termine by means of analysis the nature and the proportion of the 

 inorganic elements which are actually assimilated by an individual, 

 in order to have a minimum which might serve as a basis for any 

 reasonings or inferences on the subject. My experiments were per- 

 formed in two opposite circumstances in which I regard assimilation 

 as most rapid and most complete : videlicit, a calf in full growth, 

 and a milch-cow in calf. 



The calf was six months old, and weighed 369 lbs. Some days 



before being made the subject of experiment it was fed with hay. 



During the two days when it had this fodder ad libitum, it ate 19 lbs. 



In the course of the 1st day the calf passed 21.49 ibs. of excrements. 

 2d day " 20.39 



41.88 



Which, dried, was reduced to 7.41 lbs. 



In the course of the two days 5.584 lbs. of urine were collected, 

 which, evaporated, yielded 2933.2 grains of extract, the animal hav- 

 ing in the same interval drunk 45.7 pints of water. 



Analysis discovered in 100 : 



Of the hay Azote 1.6 Ashes 7.6 



Of the dry excrements " 2.1 " 12.7 



Of the urinous extract "4.0 " 40.0 



Now if we inquire from these data in regard to the quantity©^ 

 azote and of mineral matters which were assumed with the food in 

 the course of two days, we have : 



half-Jrachms. lialf-ilrachms. 



In the food, discarding fractions, Azote 69 Mineral substances 328 

 In the excrements " " 50.5 " 214 



In the urine " "3.8 " 38 



Together 54-3 252 



Therefore, azote fixed or exhaled in 2 days 14-7 half-drachms. 

 Mineral substances fixed in 2 days 76 " 



The composition of the ashes obtained from the hay and from the 

 excrements, shows us approximatively both the quantity and the 

 nature of the several inorganic substances which had been assimi- 

 lated. The composition of these ashes is as follows : 



Oftliehay. Of the excrements. Of the urine. 



(Carbonic 9.0 2.0 17.3 



Acids < Phosphoric 5.3 5.1 0.2 



< Sulphuric 2.4 2.3 7.0 



Chlorine 2.3 1.9 9.9 



Lime 20.4 16.0 0.9 



Magnesia 6.0 6.5 6.0 



Potash and soda 17.3 12.5 57.3 



Oxide of iron, alumina 1.5 1.0 " 



Silesia 33.7 51.0 1.2 



Lobs 2.1 1.7 



100.0 100.0 lOOO 



