THE CHANGES COME RAPIDLY 87 



weight of the silage, or as much as 0.5 per cent of the juice. The 

 source of the alcohols, as well as of the acids, is the sugar orig- 

 inally present in the plant. Experiments conducted by the writer 

 show that the amount of sugar which disappears is almost exactly 

 equivalent to the amount of alcohol and acid formed. About one- 

 half of the sugar present is ordinary cane sugar. This is first broken 

 up into simpler sugars, such as glucose, and then the simple sugars 

 are changed into alcohol and acid. 



" Other recent experiments show that the amount of simple sugars 

 in the silage is at first increased by the breaking up of some of the 

 starch; but the total amount of sugar present, after fermentation 

 is over, is much less than in the green plant material. Sometimes 

 practically all the sugar is used up. The amount of sugar in the 

 green plant, and, therefore, the amount of acid in the silage, depend 

 upon the maturity of the plant when harvested. The amount of 

 sugar in the plant decreases as the plant approaches maturity. 



"Another characteristic change is the breaking down or digestion 

 of protein matter, or the flesh-building constituent of foods. This 

 merely anticipates some of the digestive processes in the alimentary 

 tract of the animal which eats the silage, and therefore does no 

 harm, since little or no nutritive value is- lost. 



" These various changes take place with the greatest rapidity dur- 

 ing the first five days, and are practically complete at the end of 

 10 or 12 days. The writer measured the amount of carbonic acid 

 gas produced in several instances, and found that the rate at which 

 this- gas 1 was produced was always greatest during the first 24 hours 

 after the corn was put into the silo. The development of heat at 

 the surface of the silage and some of the changes in the sugar are 

 generally most rapid in the first day or two, while the formation 

 of acid is often more rapid somewhat later, or during the second, 

 third and fourth days. After the fermentative changes which have 

 just been described are finished, or after the first two weeks, there 

 is practically no further change in the silage. Silage has been 

 kept for years in a tight silo without losing either its palatability 

 or its value. 



" The losses which occur during the fermentation process are ap- 



