No. 4.] GERMAN EXPERIMENT STATIONS. 385 



the animal body. This respirations apparatus, for hirge 

 animals, to be brief, consists of a small room, size eleven 

 feet by eight feet by seven feet, with the walls made of 

 iron, and (juite air tight, with an inlet to allow the fresh air 

 to enter. 'J'he animals to be experimented upon are placed 

 in this room for twenty-four hours, and in the case of two 

 shee[) fifty cubic meters of air are drawn through per hour. 

 The air before it enters, and likewise after it has joassed 

 through the room and contains the gases breathed out by 

 the animals, is constantly sampled and analyzed, the carbon 

 of the carbonic acid and marsh gas being accurately esti- 

 mated. The carbon nudtiplied by the factor 1.3 gives the 

 percentage of fat. Now, if the per cent and amount of 

 carbon is determined in the food consumed, and the amount 

 of this element is also determined in the solid and liquid 

 excrements, and in that portion given oft' as gas just referred 

 to, the amount left ()V(>r, if any (after allowing for that 

 needed by the albuminoids), nudti})lied 1)y 1.3, represents 

 the amount of fat i)ut on by the animal during the twenty- 

 f)ur hours' experiment. If none is left over, l)ut the 

 amount of carbon taken in and given out is equal, then 

 there has been no production or loss of fat; while, if the 

 amount of carbon given out is larger than the amount con- 

 sumed, then fat has l)een actually lost. A simple illustra- 

 tion will make this })lain : — 



A sheep consunaed during twenty-four hours hay and grain con- ca'-boif. 



taining carbon, 437.17 



This carbon was given off as follows : — 



Carbon given off from lungs and skin, . . . . • . 239.25 



Carbon given off in solid excrements, 136.00 



Carbon given ofi" in liquid excrements, 19.83 



Carbon in lean meat put on in twenty -four houi's, . . . 7 . 33 



J. U Let i^« • « a ( ■ 9 « « a 



Carbon consumed, • . 



Carbon given off or put on in flesh, 



Amount of carbon remaining, . . . . . . .34.76 



34.76 C X Ijy factor 1.3 (to reduce to fat) = 45.19 grams dry fat put 

 on in twenty- four hours. 



