Vol. VIII Washington, D. C., March 6 , 1917 No. 10 
THE RELATIVE INFLUENCE OF MICROORGANISMS AND 
PLANT ENZYMS ON THE FERMENTATION OF CORN 
SILAGE 
By A. R. Lamb, 
Assistant Chemist , Iowa Agricultural Experiment Station 
PRELIMINARY DISCUSSION 
HISTORICAL REVIEW 
Ever since the fermentation of silage has been studied and discussed 
the question of the agent causing the fermentation has been in con¬ 
troversy. Some investigators have made the statement, based on 
evidence more or less incomplete, that microorganisms are solely respon¬ 
sible for the changes undergone by the ensiled forage. Other workers, 
who have based their conclusions on equally incomplete data, have 
held that in silage produced under proper conditions bacteria and 
yeasts do not figure to any appreciable extent, but that the plant cell 
itself is the cause of the chemical changes which take place in its con¬ 
stituents. Still other writers have sometimes taken sides on the sub¬ 
ject without presenting any new data bearing on the problem. 
Among the earliest workers on the chemistry and biology of silage 
formation were Burrill and Manns (3), 1 who found many species of 
bacteria in the silage, and stated that they were the cause of the chem¬ 
ical changes. Babcock and Russell (1) made silage in the presence of 
chloroform, ether, and benzene, obtaining in each case a change of 
color, some increase in acidity, and typical silage odor and flavor. 
These results and deductions made from other observations on the 
gases of the silo, the number of bacteria found, and on silage made 
from mature and immature corn led them to believe that bacteria were 
nonessential and that the cause of the fermentation was mainly the 
intramolecular changes which occur in protoplasm under anaerobic 
conditions when ordinary metabolic processes are suspended. Hard¬ 
ing (8), working under their direction, found bacteria but no constant 
flora in silage. E. J. Russell (17) came to the conclusion that the pri¬ 
mary and essential changes in silage fermentation were brought about 
1 Reference is made by number to “Literature cited,” p. 378-380. 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
hh 
(361) 
Vol. VIII, No. 10 
Mar. 6, 1917 
Key No.,Iowa— 4 
