404 



NUTRITION. 



From these and several similar determinations Liebig* has 

 constructed a table, which affords a general view of the proportion 

 between albuminates and non-nitrogenous nutrient substances in 

 the most common articles of food for man (taking the albuminates 

 as the unit). As Liebig here considers the non-nitrogenous matters 

 mainly as promoters of animal heat, and as these bodies, namely 

 the fats and carbo-hydrates, exercise a different influence on the 

 generation of heat, according to the amount of oxygen which they 

 contain, it is necessary for the simplification of the proportion 

 to take their amounts of oxygen as the measures of comparison 

 between the fats and carbo-hydrates ; ten parts of fat must thus in 

 reference to the generation of heat correspond to about 24 

 parts of starch ; sugar of milk and glucose are thus naturally 

 reduced to the corresponding value of starch by the deduction of 

 the water. On this supposition the relation of weight between the 

 plastic and the non-nitrogenous constituents of the food is as 

 follows : 



Plastic. Non-nitrogenous. 



8-8 fat. 



Andersonf has recently made very extended analyses in re- 

 ference to the nutrient qualities of different kinds of fodder for cattle. 



If we refer to what has already been stated in the general con- 

 sideration of the metamorphosis of animal matter regarding the 

 physiological importance of the separate groups of nutrient sub- 

 stances generally, and of that of the fats and carbo-hydrates 

 specially, we shall be induced to distinguish articles of food accord- 

 ing to the quantity of fat and carbo-hydrates which they contain ; 



* Chem. Briefe. 3 Aufl. 1851, S. 463, [or Letters on Chemistry. London, 

 1851, p. 361]. 



t Journal of Agriculture, 1853, p. 508-518. 



