BACTERIA AND ENZYMES IN AGRICULTURE 271 



extraordinary complexity of the phenomenon of cell chemistry, 

 even in a region so comparatively simple as the synthesis 

 of carbohydrates. Apart from the purely scientific interest of 

 researches in this direction, it is permissible to expect that an 

 extension of knowledge of the chemistry of plant assimilation 

 will render it possible more exactly to adapt the food supply of 

 the plant to its special needs, and thus to conduce to economy 

 in plant cultivation. 



The Preparation of Silage. In order to obtain a store 

 of succulent food, for use when, through severity of weather, 

 or for other reasons, it is naturally unavailable, it is a frequent 

 custom, especially in America, to resort to the operation of 

 ensilage. 



In this process the fodder, e.g., hay, beet, cabbage leaves, 

 or green maize stems, is packed into what is termed a silo, 

 which may be either a closely pressed heap, protected from 

 weather by thatch, or a large air-tight receptacle, usually 

 cylindrical in form, into which the mass is pressed. 



Under these circumstances fermentation sets in, accom- 

 panied by considerable heating. The heating is due to the 

 continued respiration of the still living cells. In course of time 

 the heat becomes such that most bacteria are killed, fermenta- 

 tion ceases, and the fermented fodder will keep for a consider- 

 able time. The character of the fermentation depends on 

 the nature of the fodder used, and on the amount of oxygen 

 and moisture present in the silo and in the original fodder 

 employed. 



Russell has carefully investigated the changes which take 

 place during the ensilage of green maizt-. The vital processes 

 of the cell protoplasm continue for some time after the maize is 

 put in the silo, the starch continues to break down and the 

 sugar formed is partially oxidised to various acids ; in the 

 limited supply of air, complete combustion to C0 2 does not 

 take place. The proteolytic enzymes of the cell act on the 



