DIETARY STUDIES. 131 



(3) Milk is a low-cost animal food in proportion to its value 

 as based upon chemical analysis. When milk is purchased at $2 

 per hundred pounds the cost of a pound of edible solids is 15.7 

 cents, while the cost of a pound of edible solids in beef at $10.50 

 per hundred pounds is 34.3 cents. This is a comparison of the 

 retail cost of milk with the cost of hind-quarter beef when pur- 

 chased by the carcass. Beef bought as steak at retail prices 

 would have a much higher comparative cost. 



(4) Notwithstanding the high quality and very general dis- 

 tribution of milk as a food, it seems by many to be regarded as 

 a luxury in the purchase of which economy must be exercised. 

 This attitude toward this particular food may in part be 

 explained by the somewhat prevalent notion that a free supply 

 of milk in the dietary is not economical, because it is supposed 

 that as much of other foods is eaten as would be the case if the 

 milk were not taken. This belief runs contrary to certain gen- 

 erally accepted facts which relate to the physiological use of 

 foods, and it only remains for experimental data to prove or dis- 

 prove its correctness. Again, milk is not given full credit by 

 people at large for its true nutritive value. Surprise is generally 

 occasioned by the statement that a quart of milk has approxi- 

 mately the food value of a pound of steak: It is important to 

 demonstrate for reasons of economy whether, as is the custom 

 with many, it is wise to purchase the least possible quantity of 

 milk and exercise little care in buying meats. . 



To investigate these questions, five dietary studies were made, 

 as follows: 



The first dietary study was made under ordinary conditions, 

 no attempt being made to select the food with any end in view, 

 except to secure the necessary variety. In the second dietary 

 the protein was secured from high-priced sources, and the milk 

 supply was kept at a minimum. In the third dietary study the 

 protein was supplied from less costly sources, and the milk con- 

 sumption was increased to a maximum. The fourth dietary 

 study was made under normal conditions, except that the milk 

 supply was limited. The fifth dietary study was also made 

 under ordinary conditions, except that milk was very abund- 

 antly supplied. 



