CATTLE FOODS NATURAL PRODUCTS 229 



brought about in other ways is a point over which there 

 has been some recent interesting discussion. 



Babcock and Russell carried on at the University 

 of Wisconsin able and very suggestive investigations 

 concerning the causes of silage formation. They con- 

 clude that the theory that silo changes under normal 

 conditions are due wholly to bacteria "does not rest on a 

 sound experimental basis." 



Their data led them to regard respiratory processes, 

 both direct by the plant cells and intramolecular, as 

 the main causes of the chemical transformations which 

 produce carbon dioxid and the evolution of heat within 

 the ensiled mass. The direct respiration appropriates the 

 oxygen confined in the air spaces of the silo, and the 

 intramolecular respiration uses oxygen combined in the 

 tissues. Both forms of respiration go on only so long 

 as the plant cells remain alive. Concerning bacteria 

 the authors say: "The bacteria, instead of function- 

 ing as the essential cause of the changes produced in good 

 silage, are on the contrary only deleterious. It is only 

 where putrefactive changes occur that their influence 

 becomes marked." 



Doubtless intramolecular respiration is continued 

 longer in immature and succulent plant tissues than in 

 tissues where the cells have reached maturity, and so the 

 losses in the silo with immature plant substance are 

 greater than with mature. Analyses of silage from 

 frozen corn and feeding trials with this material show 

 that it is not economy to cut immature corn for fear of 

 frost, as the increase of dry matter much more than bal- 

 ances the loss from the freezing. 



314. Losses in silo. Whatever are the inducing 

 causes, a careful record of what takes place in the silo, 



