MISCELLANEOUS INVESTIGATIONS 137 



apparently make larger gains when they are given a little more 

 fat in their ration than is supplied by ordinary farm feeds. 

 Soy beans are recommended as a source of protein and fat. 

 Linseed meal should also be a desirable feed from this stand- 

 point. 



Mineral Matter — The mineral matter is not under control, 

 but to make sure that the hogs ha.ve an abundant supply, it is 

 recommended to give the hogs free access to salt, charcoal, air- 

 slaked lime, bone-meal, wood-ashes, clean soil, and soft coal 

 cinders. 



How to Use the Standard. — Following is an abbreviated 

 description of the method of using the standard, as given in 

 circular 133 : 



Suppose that a bunch of pigs is two months old and weighs 

 685 pounds. The standard shows that at this time the pigs 

 require daily, per 100 pounds, live weight, 12 pounds of water, 

 .6 pound of digestible crude protein, and 2.2 pounds of 

 digestible carbohydrates. Multiplying these quantities re- 

 spectively by the total live weight, namely, 685 pounds, and 

 pointing off to the proper figure, we find that this bunch of 

 pigs will require a total of 82.'2 pounds of water, 4.11 pounds 

 of digestible crude protein, and 15.07 pounds of digestible 

 carbohydrates per day. ISText, we must make a selection of 

 feeds which we think will be suitable, and, by reference to 

 any table which gives the amount of digestible constituents 

 in one pound of each of the feeds, we must take such quan- 

 tities of the different feeds as to bring the protein and carbo- 

 hydrates up to the standard, and add sufficient water to bring 

 it to the standard also. We have now arrived at the amount 

 of feed which this bunch of pigs should consume in one day 

 when two months old. But each day the pigs will require a 

 slight increase in feed, and, since it is not practicable to weigh 

 the pigs every day and calculate our ration each day, we must 



