150 



(including]; water). These are termed Nutrients, and the composition of 



the three classes of organic compounds is roughly as follows : 



Albuminoids. Fats. Carbo-hydrates. 

 Per cent. Per cent. Per cent. 



Carbon 53.0 /6.5 44.0 



Hydrogen 7.0 12.0 6.0 



Oxygen 24.0 1 1.5 500 



Nitrogen 16.0 None None 



loo.o 100. o 1000 



These Nutrients are by no means equally distributed throughout 

 the food materials. The animal foods — meats and fish — while very 

 rich in albuminoids and fats, possess but traces of the carbo-hydrates. 

 They may be considered, therefore, essentially nitrogenous. Vegetable 

 foods as a rule contain a large percentage of Carbo-hydrates, starch 

 and sugar, and small quantities of albuminoids and fats, and conse- 

 quently may be considered as essentially ncn- nitrogenous. An exception 

 to the latter is to be found in peas and beans, which contain a notable 

 amount of albuminoids. Very tat meats on the other hand, by reason 

 of the large amount of fat they [jjssess, cannot be considered as highly 

 nitrogenous. 



This great distinction between these classes of foods is one 

 worth remembering as helping us to arrive at their true nutritive value. 

 To enable us to do this the better, however, we may no.v proceed to 

 state the physiological functions of these nutrients, whether they be 

 derived from animal or vegetable foods. For this purpose I shall lake 

 the liberty of placing before you another chart from the National 



Museum. 



Uses of Food in the Body. 



Food supplies the wants of the body in several ways. Food fur- 

 nishes : 



1. The materials of which the body is made. 



2. The materials to repair the wastes of the body and to protect 



its tissues from being unduly consumed. 

 Food is consumed in the body as fuel to 



3. Provide heat to keep it warm ; 



4. Produce muscular and intellectual energy for the work it has to do 



