230 Agricultural Bacteriology. 



on account of the lack of free oxygen. The carbon diox- 

 ,ide that is formed in the silage is heavier than the air 

 and does not pass out of the silage, hence, there is no op- 

 portunity for the oxygen to enter from the surface. It 

 the silo is not perfectly tight at the bottom and on the 

 sides, the air will penetrate for some distance, and allow 

 the molds to develop and cause the silage to spoil. If 

 the silage is removed from the silo and placed in a loose 

 pile, the molds at once begin to grow because of the abun- 

 dant supply of oxygen, thus furnished. 



The plant cells in their respiration produce heat just 

 as the animal does in its breathing. In the case of the 

 living plant, the heat passes off as rapidly as formed. 

 In the mass of material in the silo, the heat produced 

 can not be radiated as rapidly on account of the volume, 

 hence, the temperature of the silage rises to 120 F. or 

 above. This high temperature is retained for a long 

 time and prevents the freezing of the silage, a very for- 

 tunate circumstance without which it would be very diffi- 

 cult to use this method of preserving fodder in the north. 



If the plant cells are dead because the plant is ripe, or 

 because of being frozen, the oxygen of the air in the 

 silage is not used, and molds are able to grow. Acids 

 are not formed by the decomposition of the sugars and 

 consequently various kinds of bacteria are also able to 

 grow. The result is a rotten mass instead of a fermented, 

 but succulent and nutritious feed. It is desirable to al- 

 low the corn to become \vell matured, as the silage formed 

 is not as acid as is that prepared from the more immature 

 corn. This is due in part to the difference in the compo- 

 sition of the plant at different stages. If the corn or clo- 

 ver is somewhat wilted, the cells cannot respire even 

 though they are not dead. If water is added to the silage 



