FEEDING OF ANIMALS. 285 



In fact, the experimentally determined relation of the non- 

 nitrogenous, and of the nitrogenous constituents of the food, 

 respectively, to the amount of increase produced ; the com- 

 position of fattening increase generally ; the relatively greater 

 tendency to grow in frame and to form flesh with highly 

 nitrogenous food; the greater tendency to form fat with 

 food comparatively rich in non-nitrogenous substances, and 

 especially in carbohydrates ; and common experience in 

 feeding — all pointed in the same direction. 



For some years there was little or no discussion on the Liebig's 

 subject, and it seemed to be tacitly admitted, both on the m ^^ p ' 

 Continent and in this country, that the views of Liebig, as to 

 the formation of at any rate much of the fat of the herbivora 

 from carbohydrates, were correct. 



In 1865, however, at a meeting of a Congress of Agri- Views of 

 cultural Chemists, held at Munich, in August of that year, j^ e ^ 

 Professor Voit, from the results of experiments made in ko/er. 

 Pettenkofer's respiration apparatus, with dogs fed chiefly on 

 flesh, maintained that fat must have been produced from 

 nitrogenous substance ; and that this was probably the chief, 

 if not the only, source of the fat even of herbivora. 



Pettenkofer and Voit further maintained, that to establish 

 the formation of fat from the carbohydrates, experiments 

 must be brought forward in which the fat deposited was in 

 excess of that supplied by the food, plus that which could be 

 derived from the transformation of albumin. 



Of course, the mere fact that the food consumed contained 

 enough nitrogenous substance for the formation of all the 

 fat that had been produced, would of itself be no proof that 

 that substance had been its exclusive source. On the other 

 hand, if the amount of fat stored up in the animal was in 

 excess of that which could be derived from the ready-formed 

 fatty matter of the food, and from the transformation of the 

 nitrogenous substance, it would be proved that at any rate 

 some of the stored-up fat must have had another source — 

 and this could only be the carbohydrates. 



Accordingly, the results of many of the Rothamsted feeding 

 experiments were calculated, to ascertain whether or not the 

 ready-formed fat, and the nitrogenous substance of the food, 

 were sufficient to account for the whole of the fat estimated 

 to have been stored up. None of the experiments had been 

 specially arranged with a view to the elucidation of this 

 question. In some of them, however, what may be called 

 minimum amounts, and in others excessive quantities of 

 nitrogenous substance, had been consumed. Some of the Rotham- 

 results seemed to us to afford clear evidence on the point, stedresvits - 

 and we gave a paper on the subject in the Physiological 



