768 
Journal of Agricultural Research 
Vol. XXI, No. 10 
enzyms were the primary and essential factors in silage fermentation 
and that bacteria played a minor part. 
Esten and Mason (6) attributed the fermentation largely to the work 
of bacteria and yeasts. They concluded that there were three chief fer¬ 
mentations, lactic acid, alcohol, and acetic acid. The primary change 
was the fermentation of sugar by organisms similar to the common milk- 
souring organisms which converted it to lactic acid. The secondary 
change was produced by yeast which converted the remaining sugar to 
alcohol, the acetic acid bacteria then oxidizing the alcohol to acetic acid. 
Samarani (17) believed that the sugars were transformed to alcohol 
and later oxidized to acetic acid by respiration of plant cells. The for¬ 
mation of lactic acid was the result of the action of a bacillus and a coccus 
which he found in almost equal proportions. He thought the organisms 
were the same as those that are common in milk fermentation. 
Hunter and Bushnell ( 13 ) conclude that microorganisms cause the 
major fermentation of silage. TLhey found large numbers of organisms 
belonging to the bulgaricus group present and state that these organ¬ 
isms are responsible for the high acid content of silage. Organisms 
belonging to the bulgaricus group and the colon group produce the 
greater part of acetic acid. Sherman ( 18 ) has also shown that silage 
contains large numbers of the organisms belonging to the bulgaricus 
group. 
Lamb ( 14) states that— 
neither microorganisms nor plant enzymes are alone responsible for the changes in 
silage fermentation. 
Microorganisms are largely responsible for the production of acid and 
the disappearance of sugars. He also states that the formation of alco¬ 
hols and the hydrolysis of protein as indicated by the amino-nitrogen 
content are primarily due to cell respiration, although later in the fer¬ 
mentation microorganisms show some activity in both processes. 
Hunter (n) has shown that the heat production in forage silage is 
due to microbial activity and not to intramolecular respiration of plant 
tissue. In his studies on alfalfa silage ( 12 ) he found that alfalfa alone 
made a silage of inferior quality but that upon the addition of an available 
carbohydrate supplement a good quality of silage could be produced, 
^he protein hydrolysis of alfalfa silage as indicated by the amino-nitrogen 
and ammonia determinations was greater than when a carbohydrate 
was present. Round (13), working on the fermentation of sauerkraut, 
found that cell respiration plays a more important part than was for¬ 
merly thought. 
Sherman and Bechdel (19), working on the fermentation of corn 
stover silage, found that it undergoes fermentation similar to com silage. 
The following statement is also made: 
From a review of the present status of the question as to whether bacteria or plant 
cells are mainly responsible for silage fermentation, it is concluded that the data thus 
far published are inconclusive. Although the results of the present study tend to 
support the cell respiration theory, conclusions on this point arc withheld. 
