FOOD 



93 



Food must supply the needful material for the repair of 

 these tissues, it should therefore consist of : — 



Nitrogenous matters, 

 Non-nitrogenous matters. 

 Mineral matters. 

 Water. 



None of these must be absent, one cannot replace the 

 other ; further, one can only act satisfactorily in the pre- 

 sence of the other. 



The following classification of foods is generally adopted : 



Nitrogenous 



fProteids and albu- 

 1 minoids. 



Organic^ 



Non-nitrogenous jOa^-bo-iiydrates fats, and 

 I [ vegetable acids. 



Inorganic : Mineral salts and water. 

 Each of these groups must be considered in detail. 



NITBOGENOUS OB PEOTEID SUBSTANCES. 



The type of all nitrogenous matter is albumen, by which 

 the name of the class is commonly known. It is not a 

 single nor a simple substance, but a highly complex group, 

 possessing certain chemical features in common, and others 

 characteristically different, by which their grouping is 

 mainly determined. 



The class termed Peoteids consists of native albumens, 

 derived albumens, globulins, fibrins, albumoses, and peptones. 



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