340 FEEDING ANIMALS. 



of urea leaves a kind of fatty matter, as the residue of the 

 albuminoids, and this is used to keep up animal heat, and 

 the surplus goes to lay on fat or produce oil in milk. 

 These chemists were inclined to doubt whether carbo- 

 hydrates, such as starch, sugar, gum, and cellulose, were 

 ever used in the animal system to produce fat, as Leibig 

 had held many years before ; but their experiments were 

 far from being conclusive, as they had omitted to experi- 

 ment upon the pig. Lawes and Gilbert carried out a thor- 

 ough series of experiments upon pigs, that fully corrobo- 

 rated Liebig's views, and proved quite decisively that 

 carbo-hydrates were transformed into fat. The pigs were 

 fed upon barley-meal, and the fat and albuminoid matter 

 in the barley-meal were wholly insufficient to account for 

 the fat formed in the bodies. It has been stated that 

 these German chemists have recently acknowledged the 

 correctness of the experiments of Lawes and Gilbert, and 

 that carbo-hydrates must be considered as a source of 

 fat in animal bodies. In this they acknowledge the far- 

 sightedness of their great predecessor, Leibig, whose mind 

 seemed to grasp great truths intuitively, and who was 

 much less liable to error than those who draw general 

 conclusions from limited practical experiments. 



The practical common sense of feeders has taught them 

 that foods having a large proportion of starch, such as 

 corn-meal, barley-meal, rye-meal, and fine middlings from 

 wheat, are particularly adapted to produce fat, or milk 

 rich in butter. And these impressions, derived from gen- 

 eral practice, have withstood all the doubts of scientific 

 investigators based upon inadequate experiments. 



VARIETY OF FOOD FOE MILK. 



We have seen that milk is a very complex fluid, contain- 

 ing all the component elements of the animal body. The 

 food, therefore, to produce it, should be rich in all these 



