THE PREPARATION OF FARM PRODUCTS. 299 



Certain other food materials are similarly used and similarly 

 fermented. A form of soured food is made from beans in 

 certain countries, which is in a similar way allowed to undergo 

 an acid fermentation. So little is known in regard to the real 

 nature of these products that we can at present do no more 

 than simply mention them. 



IV. SILAGE. 



In the silo the agriculturist has devised a method of utiliz- 

 ing certain food products of which the soil yields him large 

 crops, but which contain large amounts of water and which 

 lose their value, in great measure, when dried. Moreover the 

 silo not only enables him to preserve such food, but it impreg- 

 nates the food with new flavors and a new character which, in 

 some respects, enhance its value, since they make a product 

 especially relished by cattle. The preparation of silage involves 

 a fermentation of a very marked character. It is a fermentation 

 which, until recently, has been regarded as due to bacterial ac- 

 tion, although the subject was little understood and not care- 

 fully investigated. The recent, more careful studies have shown 

 that here, as in the tobacco fermentation, bacteria play a part 

 of less importance than formerly believed and that, under cer- 

 tain circumstances, the silage fermentation may take place 

 without the aid of bacteria, suggesting perhaps that the whole 

 process is a means of preventing their growth rather than 

 stimulating it. 



Preparation. In the preparation of silage the material to be 

 used, most commonly corn, although other succulent vegetable 

 material may be utilized, is cut into moderately small pieces 

 and packed away firmly in a solid mass in a tall air-tight com- 

 partment. Sometimes the silo is filled rapidly and sometimes 

 more slowly, with somewhat different results in the two cases. 

 After the silo is filled it is closed at the top, and frequently 

 subjected to considerable pressure. The contents are thus 



