248 CKOPS. XI. 



/CHiCH 

 partly to coumarin, C 9 H, ; Oo, or C ( ;H 4 <f which occurs in 



\0 . CO, 



woodruff (Asperula odorata), in Bokhara clover (Melilotus), in 

 sweet-scented vernal grass (Anthoxanthum odoratum), and pro- 

 bably in many other plants. 



Coumarin is a crystalline solid with a characteristic odour 

 (that of new-mown hay), is slightly soluble in water, and very 

 soluble in alcohol. Its odour becomes very pronounced when 

 plants containing it are dried. 



Ensilage or Silage is made by preserving green fodder in a 

 closely compacted condition so as to prevent access of air as 

 much as possible and so hinder the various fermentative changes 

 from proceeding beyond a certain stage. Originally all silos 

 consisted of pits or buildings of stone or wood, in which the 

 materials could be stored and subjected to high pressure. It 

 is now a common practice to simply stack the fodder in the 

 green state, treading or pressing it down as much as possible, 

 and finally weighting it with stones or earth. In all cases the 

 outside of the silo, where air has access, becomes so rotten as 

 to be useless, but the amount of waste is not very great. 



The changes which occur in the silo are in many respects 

 similar to those in the stack, but fermentation is limited in a 

 different manner by air exclusion, while in a stack it is chiefly 

 from lack of sufficient moisture. Consequently it is found that 

 the relative progress of different organisms is different in the 

 two cases. Moreover, in a silo the predominant character of 

 the fermentation, and consequently of the silage, depends 

 largely upon the management. If the silo be made slowly, so 

 that a considerable amount of heating may occur before the 

 weighting expels the air, the temperature rises so high (up to 

 55 or 60) that the bacteria which produce acids (e.g., 

 acetic, lactic, and butyric acids) are destroyed. The resulting 

 product is then known as " sweet" silage. If the silo be built 

 with little delay and compressed at once the temperature does 

 not rise so high, and the acetic, lactic, and other acid-producing 

 bacteria are not killed, but produce their characteristic pro- 

 ducts, thus leading to the formation of " sour" silage. 



