Digestion, Respiration and Calorimetry. 37 



the 2.28 pounds of increase. We learn from the above that 

 during one day of the experiment the ox took into its body 171.8 

 pounds of material in oxygen, water and dry matter, and from it 

 built up 2.28 pounds of body substance, which consisted of .48 

 pounds of albuminoids or lean meat, .61 pounds of fat, .02 

 pounds of mineral matter, which went mainly to the bones, and 

 1.17 pounds of water, placed mostly with the lean meat and, in 

 less proportion, with the fatty tissue. 



Where the animal produces other substances than flesh, as in 

 the case of sheep and mUch cows, the method of calculating 

 production is the same as with oxen, though somewhat more 

 complicated. 



III. Calorimelry. 



60. Measuring the heat units of feeds. — The calorimeter is a 

 device so arranged that when a given substance is burned therein 

 the heat given off is taken up by water and can be accurately 

 ascertained. While investigations have been in progress with 

 the respiration apparatus to determine what becomes of the food 

 taken into the body, other workers have endeavored by means of 

 the calorimeter to ascertain the heat units of food materials. It 

 has been found that the results obtained with the respiration 

 apparatus and the calorimeter agree very closely; that is to say, 

 in supplying the body with fael, the protein, fat and carbohy- 

 drates of the food have been found to replace each other in almost 

 exact proportion to the heat units they evolve when burning. 

 Prof. Riibner found the quantity of material equal to 100 parts 

 of fat to be as follows: 



Equivalent for 100 parts of fat as shown by the respiration apparaiu* 



and calorimeter. 



