CORN 173 



preserving meat and hay by drying, and in preserving 

 many articles by cold storage. Hay is well preserved by 

 drying, but corn fodder retains so much water that when 

 put in a barn or stack it will usually spoil. Certain sub- 

 stances prevent the action of decay organisms. These 

 preservatives are usually harmful to men and animals, 

 so that this is not a very desirable method of preserving. 

 Salt is satisfactory for preserving meat and some other 

 things, because the harmful excess of it can be washed 

 out. A fourth method of preserving is that used in can- 

 ning fruit. This is the principle employed in the silo. 

 By heating fruit so as to kill the decay organisms and 

 then sealing it air-tight, so that no more can get in, it 

 may be preserved indefinitely. 



In the early attempts to keep silage, it was placed in 

 pits or tanks and sealed with earth or other material, 

 and was cooked with steam. Later it was found to keep 

 nearly as well when merely packed in the silo. Decay 

 begins at once, and as a result the silage becomes very 

 hot. This decay uses up the air in the silo and changes 

 it to carbon dioxid. This process continues until the heat 

 and the exhaustion of the air stop the decay. The silage 

 will then keep indefinitely, provided no air can get into 

 it. That on the top of the silo or near any leaks will spoil. 

 As soon as the silo is filled, it is well to begin feeding 

 from it. If this is not done, it may be covered with chaff 

 and well wet down. Or the corn may be husked from the 

 last that is put in and the silage itself act as cover; several 

 inches on the surface will spoil. There should not be too 

 much surface area per cow, or it will spoil while being fed. 



162. The Silo. Any kind of materialmay be used for 



