180 BOARD OF AGRICULTURE. [Pub. Doc. 



The shad has 85 per cent of refuse and moisture, and at 25 

 cents per pound the nutrients cost 11.75 per pound. 



I am aware that I have selected some of the more costly 

 foods, but they are such foods as people even in moderate 

 circumstances purchase as necessities. If I had selected 

 others, the fact would have been unchanged that when we 

 compare pound with pound of clear, solid food, free from 

 any waste or refuse, milk is one of the cheapest foods there 

 is. Many consumers regard it as a luxury, to be bought by 

 the pint and used sparingly. AVere its cheapness as a food 

 fully understood, its use would be greatly increased and the 

 surplus would be greatly reduced. 



But what kind of food do we get for this money? The 

 answer necessitates a brief explanation of the uses of food. 



The human machine, like the steam engine, must have food 

 to develop warmth and force. The human machine, like in- 

 animate machinery, is continually wearing, and the worn-out 

 parts must be replaced ; but the human machine is built up 

 and the wear made good by growth from within. Special 

 food is required for each function, hence we need fuel foods 

 and wear-and-tear foods. The fuel quality of the fuel foods 

 can be measured, and the amount needed by the human sys- 

 tem under difterent conditions has been estimated. The car- 

 bon principle predominates in these foods, and they are 

 frequently called carbohydrates and fats. The calorie is 

 the unit of measurement, and a man doing a moderate 

 amount of work needs 3,500 calories per day. 



The wear-and-tear or building-up foods have nitrogen as 

 the leading essential constitutent, and in the form needed for 

 food are called protein. A man doing moderate muscular 

 work needs .28 pounds of protein per day. 



Now, 1 quart of milk contains .08 of a pound of protein 

 and 650 calories, or approximately one-fourth of the amount 

 of both fuel and wear-and-tear foods needed to support a man 

 one. day doing moderate muscular work. Hence we find as 

 other points concerning the food value of milk that it is not 

 only cheap, but that it has the proper kinds of food and in 

 correct proportions. 



Protein, Pounds. Calories. 



Needed by man doing moderate work, . 28 3,500 



In four quarts of milk, . . . .32 2,600 



