AUTHOR'S METHOD OF FEEDING 161 



Ether Extract Requirement. As determined by the 

 writer, pigs will make larger gains if they are given a 

 little more fat in their ration than ordinarily is present 

 in the common feeds of the farm. Soy-beans contain more 

 than the ordinary amount of fat or ether extract; conse- 

 quently if this feed is used in a ration, it will be better 

 than when other feeds not containing as large a quantity 

 of fat are used. 



Mineral Matter Requirement. Since the amount of 

 mineral matter present in the soil, in the water, in the 

 vegetation and in different feeds, as previously stated, is 

 so decidedly variable, and since there is no standard for 

 the requirement of mineral nutrients by the pig, it seems 

 necessary, in order to get best results in pig feeding, to 

 give the pig free access to a variety of mineral substances 

 so that he can supply, according to the dictates of his 

 appetite, whatever is deficient by way of mineral sub- 

 stances in his feed. In order to supply these mineral 

 substances the results on the Illinois Experiment Station 

 farm seem to be quite satisfactory if the pig is given free 

 access to salt, charcoal, ground lime stone, bone meal, 

 wood ashes, clean soil and soft coal cinders. These, 

 with the exception of the last two, are kept in different 

 compartments of a trough before the pigs at all times. 



THE PIG AS A MACHINE. 



In order to illustrate further the efficiency of the animal 

 body as a machine for converting feed into pork, atten- 

 tion as directed to a farm operation with which all are 

 familiar. 



Suppose a field of wheat in the shock that is to be 

 threshed with a steam thresher and sheaves of wheat are 

 to be used with which to fire the engine. After the engine 



