160 PRINCIPLES OF RURAL ECONOMICS 



as a breadstuff, or the substitution of potatoes for bread, etc. 

 Such changes are likely to occur as the world becomes more 

 thickly populated ; in fact they must occur if the population 

 increases very rapidly over a considerable period of time. It 

 would, however, be economical for some countries to change 

 their habits in this direction without regard to the question 

 of population. 



That milk is a more economical food than meat is shown by 

 the fact that the milk furnished by one good dairy cow in the 

 course of a year has a food value equal to from 3000 to 4000 

 pounds of beef. It will take five or six beef cattle to lay on that 

 much first-class beef in a year, and they will together consume 

 as much feed as three or four of these dairy cows. Therefore 

 it would be a great economy of land if people would consent to 

 consume more milk and less beef. This, however, is counter- 

 balanced at the present time by the fact that the milk for the 

 great centers of consumption must be produced near at hand, 

 where land is scarce, whereas beef may be produced in new 

 countries at great distances from the centers of consumption, 

 where land is so cheap and abundant that it does not need to 

 be severely economized as yet. Moreover, where beef can be 

 produced under range conditions, it costs less labor per unit 

 of food value than milk does. But a time may come when 

 such a change in diet would be highly economical, either by 

 reason of the settling of the last of these new countries, 

 or, as is more likely, by the discovery of cheaper and more 

 satisfactory ways of preserving milk so that it also may be 

 transported greater distances. But either of these changes will 

 bring about such a change in the relative price of milk and 

 beef as to bring about a change in the relative consumption 

 of these two articles, there being always a tendency to substi- 

 tute a cheaper for a dearer article where the two serve the 

 same purpose. 



