THE CHEMISTRY OF COOKERY. 825 



I might quote a multitude of other palpable inconsistencies of the 

 theory, which is so slippery that it can not be firmly grasped. Thus, 

 Dr. Pavy (page 403), immediately after describing bacon-fat as "the 

 most efficient kind of force-producing material," and stating that " the 

 non-nitrogenous alimentary principles appear to possess a higher die- 

 tetic value than the nitrogenous^'' tells us that " the performance of 

 work may be looked upon as necessitating a proportionate supply of 

 nitrogenous alimentary matter," his reason for this admission being 

 that such nitrogenous material is required for the nutrition of the mus- 

 cles themselves. 



A pretty tissue of inconsistencies is thus supplied ! Non-nitrogenous 

 food is the best force-producer — it corresponds to the fuel of the steam- 

 engine ; the nitrogenous is necessary only to repair the machine. Never- 

 theless, when force-production is specially demanded, the food required 

 is not the force-producer, but the special builder of muscles, the which 

 muscles are not used up and renewed in doing the work. 



It must be remembered that the whole of this modern theoretical 

 fabric is built upon the experiments which are supposed to show that 

 there is no more elimination of nitrogenous matter during hard work 

 than during rest. Yet we are told that " the performance of work 

 may be looked upon as necessitating a proportionate supply of nitro- 

 genous alimentary matter," and that such material " is split up into 

 two distinct portions, one containing the nitrogen, which is eliminated 

 as useless." This thesis is proved by experiments showing (as asserted) 

 that such elimination is not so proportioned. 



In short, the modern theory presents us with the following pretty 

 paradox : The consumption of nitrogenous food is proportionate to 

 work done. The elimination of nitrogen is not proportionate to work 

 done. The elimination of nitrogen is proportionate to the consumption 

 of nitrogenous food. 



I have tried hard to obtain a rational physiological view of the 

 modern theory. When its advocates compare our food to the fuel of 

 an engine, and maintain that its combustion directly supplies the mov- 

 ing power, what do they mean ? 



They can not suppose that the food is thus oxidized as food ; yet 

 such is implied. The work can not be done in the stomach, nor in the 

 intestinal canal, nor in the mesenteric glands or their outlet, the tho- 

 racic duct. After leaving this, the food becomes organized living 

 material, the blood being such. The question, therefore, as Between 

 the new theory and that of Liebig must be whether work is effected 

 by the combustion of the blood itself, or the degradation of the working 

 tissues, which are fed and renewed by the blood. Although this is so 

 obviously the true physiological question, I have not found it thus 

 stated. 



Such being the case, the supposed analogy to the steam-engine 

 breaks down altogether ; in either case, the food is assimilated, is con- 



