170 MAKUAL OF CATTLE-PEEDTNG. 



daily, while direct determinations of tlie respiratory pro- 

 ducts of dogs twice as large and in the best condition 

 give much smaller numbers. 



In the body of the animal, winch was killed at tlxe end 

 of the experiment, 1,352.7 grammes of fat wore found on 

 the various organs, instead of the 160 grammes which, ac- 

 cording to other investigations, was the greatest amount 

 that could have been present in the body after thirty days' 

 fasting, so that in this case about 250 grammes daily of 

 the fat of the food remained nndestroyed and were de- 

 posited in the body. In numerous other experiments on 

 dogs, too, with a more normal food of meat and fat, and 

 with help of the respiration apparatus, the fact has been 

 confirmed that often a very considerable part of the fat of 

 the food may be retained in the body. 



The fat, however, must be analogous to the animal fats 

 or easily altered into them, since entirely foreign fats are 

 either not resorbed from the alimentary canal at all or are 

 rapidly oxidized. This does not, of course, prevent the 

 fat in the fodder of the herbivora from contributing di- 

 rectly to the deposition of fat in the body, since most of 

 the vegetable fats are very similar in their composition 

 and properties to the animal fats. 



Forraation of Fat in the Body. — For the fact of 

 the formation of fat in the body from other substances 

 no special proofs need be adduced ; it is sufficiently evi- 

 dent from daily experience, especially in fattening and in 

 milk-production. 



But it is of importance to consider the question what 

 nutrients yield chiefly or exehisively the necessary mate- 

 rial for the formation of fat. 



Naturally only the albuminoids and carbhydrates are to 

 be considered in this connection, for besides these nutri- 



