2 
begin its study of the best method of fitting its vegetable food 
supply to its digestive provisions. 
e must remember that only a portion of almost any food 
can become fitted for assimilation by our body, the remainder 
being rejected as waste. The portions which are thus used are 
called nutrients, and one of the functions of digestion is to 
separate them from the foods that we eat. These nutrients are 
of different classes. Those which are inorganic include such 
substances as water, iron and the lime salts. The organic nu- 
trients are divided into those which contain nitrogen, called 
albuminoids, and those which do not, the latter known as 
carbonaceous. Some of the latter, as sugar, starch and inulin, 
contain two atoms of hydrogen for each atom of oxygen, as in 
water (H.O) and are therefore called carbohydrates, while those 
not based on this formula, as the fats, are called hydrocarbons. 
The carbohydrates become at least partly converted into fat 
by the body, but this is done at the expense of considerable 
labor by the system, while the fat eaten calls for very little such 
labor. A given weight of fat in the food is therefore rated as 
about four and a half times as valuable, as a nutrient, as the 
same weight of carbohydrate. A pound of albuminoid is re- 
garded as equally valuable with a pound of fat. We are thus 
enabled to readily calculate the relative nutritive values of 
different foods. Suppose, for example, that we have three foods 
with the composition given below: 
Carbohydrate Hydrocarbon Albuminoid 
ee anenerces ee 40 4 6 
i eticaters gumiceneameaiste 20 2 3 
ieee 49 7 I 
Reducing each set to carbohydrates, we get the following 
results: 
A B Cc 
Carbohydrates.......... 40 20 49 
Hydrocarbons .......... 4X4% 18 2X4% 9 7X 4% 31.5 
Albuminoid 6 X4¥% 27 3X44 13.5 1X4 45 
85 8s 
The number of nutritive units in A and C is the same, so that 
the money value per hundredweight of these two would agree, 
while that of B would be only half as great. 
