60 Messrs. J. E. Lawes and J. H. Gilbert on Food in its 



of the estimated total consumed portions of animals admitted 

 to be in only a proper condition of fatness into its starch 

 equivalent, there was, on the average, a higher proportion of 

 so -reckoned non-nitrogenous substance to one of nitrogenous 

 substance in such animal food than in bread itself. It was con- 

 cluded, indeed, that, on the large scale, the introduction of 

 animal aliments into our otherwise chiefly farinaceous diet did 

 not increase, but diminish the relation of the nitrogenous or so- 

 called "flesh-forming," to the non-nitrogenous constituents 

 (reckoned according to their respiratory and fat-forming capa- 

 city) in the collective food. The important bearing of these 

 facts in forming an estimate of the characteristics of different 

 human dietaries will be at once apparent. 



So much, then, for the characteristic food requirements of 

 animals exposed to as little exertion as possible, and fed with 

 the express view of accumulating flesh and fat in their bodies. 

 Concurrently with the earlier experiments to determine the re- 

 lations of food and body-weight and increase above referred to, the 

 question of the relation of the amount of the constituents voided 

 (especially the nitrogen) in the liquid and solid excrements to 

 that in the food consumed, was also investigated. Consistently 

 with the results obtained in regard to the amount and character 

 of the increase resulting from the consumption of very different 

 amounts of nitrogenous substance, it was found that the amount 

 of nitrogen voided by fattening animals fed under equal con- 

 ditions as to the exercise of force, bore a very direct relation to 

 that supplied in the food. So direct, indeed, is the connexion 

 between the composition of the matters excreted and that of the 

 food consumed, that we have constructed Tables showing the 

 relative value of the manure produced by fattening animals from 

 a given weight of different food-stuffs according to the com- 

 position of the latter. 



But more to our present purpose — so striking were the re- 

 sults obtained in regard to the connexion between the composi- 

 tion of the food on the one hand, and the amount consumed, 

 the amount and character of the increase produced, and the 

 composition of the excreted matters, on the other, and, on 

 some important points, so contrary in their indications to the 

 prevailing views, that we were led at once to turn our attention 

 to human dietaries, and especially to a consideration of the 

 management of the animal body undergoing somewhat excessive 

 labour, as, for instance, the hunting horse, the racer, the cab- 

 horse, and the fox-hound, and also pugilists and runners. The 

 conclusions to which we were led by this study were briefly 

 summarized in 1852 as follows*: — 



* ReportcftheBritishAssociationfortheAdvancementof Science forl852. 



