206 AGEICULTUEAL AND INDUSTRIAL BACTBEIOLOGY 



If air gains access to the silage, molds will soon develop 

 and oxidize the lactic acid to carbon dioxide and water, and 

 putrefactive changes may then be brought about. Moldy 

 silage, of course, has lost much of its feeding value and is 

 dangerous particularly for horses. 



The organisms responsible for bringing about the fei*- 

 mentation are members of the genera Bacterium and 

 Lactobacillus for the most part. Organisms closely resem- 

 bling if not identical with Lactobacillus bulgaricus and 

 Bacterium aerogenes are usually abundant. The character- 

 istic odor of good silage is due to the presence of certain 

 volatile acids and to the formation of esters with the traces 

 of alcohol present. 



Carbon dioxide may be produced in considerable amounts 

 during the fermentation of the silage. Care should be used, 

 therefore, in entering a silo which is partly filled with 

 silage. It may be recalled that carbon dioxide is heavier 

 than air and that there are numerous cases of asphyxiation 

 on record where care has not been used to see that the silo 

 is free from this gas in injurious quantities. The danger 

 would be particularly great in a silo where the process of 

 filling has been interrupted and men enter the silo a few 

 days later to tramp down new silage as it enters. 



The fact that the fermentation is essentially anaerobic 

 and that there are organisms present, such as members of 

 the genus Bacterium, which produce not only carbon 

 •dioxide but hydrogen as well, leads to strong reducing 

 action. Considerable amounts of sugar are transformed 

 into the polyatomic alcohols. Fructose especially is con- 

 verted into mannitol (CeHi^Oj). 



Sauerkraut. — Sauerkraut is prepared by shredding or 

 slicing cabbage, mixing with salt and pressing firmly into 

 casks or vats. The sugary juices of the cabbage leaves 

 together with the salt soon form a liquid which covers the 

 mass. Lactic acid fermentation, brought about largely by 



