PEODTJCTION VALUE OF FOODS 127 



The relative value of the different foods for the 

 production of increase is shown by the Calories in 

 the right-hand column. Digestible albuminoids, starch, 

 sugar, and soft cellulose, appear all to have a very 

 similar value, while the oil has 2J times the value 

 of starch. The straw pulp contained more than one- 

 third its weight of furfuroids (oxy celluloses, &c.), these 

 evidently, therefore, took part in the formation of fat. 



Kellner concludes from his experiments that 100 

 parts of digested starch may yield a maximum of 23'3 

 of fat in the body, the rest of the starch being con- 

 sumed in the transformation process. Of the pure 

 albuminoid used (wheat gluten), 7 per cent, of the 

 available heat value was in his experiments stored up 

 in the animal as nitrogenous tissue, while 38 per cent, 

 was stored up as fat. Turning these heat values into 

 weights it appears that 100 parts of digested gluten 

 produced about 7 parts of dry nitrogenous increase, 

 and 19 '8 parts of fat. The proportion of nitrogenous 

 increase to fatty increase may be expected to vary 

 under different circumstances. 



The increase in live weight obtained by feeding with 

 albuminoids, starch, sugar, or fat, will not necessarily 

 take place in the proportions shown by the calorific 

 values of these foods, nor in the proportions of their 

 capacity for producing fat ; this will be due to the 

 varying proportions of lean flesh and fat which will 

 be formed under various circumstances, and to the 

 fact that when albuminoids are stored up as lean flesh 

 they are always associated with much water, while a 

 purely fatty tissue contains very little water.^ The 



• Lean flesh will contain about three parts of water to one of dry 

 nitrogenous matter. Purely fatty tissue, as kidcey fat, will contain 

 only about 5 or 6 per cent, of water. 



