406 ENSILAGE. 



are favourable. When grass freshly cut is put into a heap these 

 organisms, or ferments, as they are called, find in the stillness, 

 warmth, and moisture of the air within the heap a set of condi- 

 tions favourable to their rapid development, and they increase 

 with enormous rapidity, and attack and live upon the tissues of 

 the fodder. Vegetable matter is their food, just as it is the food 

 of cattle. There are many different kinds of them. One set of 

 them lives chiefly upon the carbohydrates or starchy and sugary 

 matter of the plant, converting these into alcohol, and at the 

 same time producing carbonic acid gas. These are organisms 

 resembling yeast, and they produce the alcoholic fermentation. 

 Another set carry the process a stage further, and convert the 

 alcohol into acetic acid or vinegar, producing the acetic fermenta- 

 tion. There are others producing various other kinds of products, 

 such as lactic acid, the acid contained in sour milk, and butyric 

 acid, the acid found in rancid butter. All these and many 

 others prey upon the carbohydrates of the plant. There are 

 other exceedingly minute organisms of a different kind, which 

 attack chiefly the albuminoid constituents of the fodder, decom- 

 posing them and converting them into various nitrogenous 

 substances less complex than albumen, which have no feeding 

 value. Among the j)roducts of this decomposition are ammonia 

 and allied substances having a strong pungent and disagreeable 

 odour. These ferments are known under the name of bacteria, 

 and they produce what is called the ^:)?^.^W(i fermentation. Their 

 name is legion, and their nature is little understood ; but the 

 result of their work is that the fodder putrefies or becomes 

 rotten. There are other living organisms which follow upon 

 these, but it is needless to pursue the subject further, for it is 

 not the last but the first stages of fermentation with which we 

 are here concerned. The object to be attained in making 

 ensilage is to prevent these organisms from carrying on the 

 changes referred to. If we could stop their changes at the 

 beginning, we should have perfect ensilage, but the further we 

 allow the fermentative change to go on, the worse and worse 

 the ensilage becomes. What chiefly interests us here is to know 

 how these ferments may be killed or rendered inactive, without 

 doing injury to the fodder. There are several ways in which 

 this can be done. Like all other living creatures, they require 

 air, warmth, and moisture ; if they are deprived of oxygen, or 

 subjected to extreme cold or great heat, or if they are dried up, 

 they die, and even if these means are not carried to an extreme 

 degree their lives may be rendered comparatively inactive. Thus, 

 when grass is rapidly dried in the sun, and converted into hay, they 

 have not moisture enough to favour their growth and develop- 

 ment, and their work is almost put an end to, so that hay can 

 be kept for a long time in the air with very little change. If 



