Mar. 6, 1917 
Fermentation of Corn Silage 
363 
some of the principal manifestations of bacterial activity are identical 
with those of enzym action, as, for example, the evolution of carbon 
dioxid, production of alcohol, rise in temperature of medium, and hydroly¬ 
sis of protein. Antiseptics, if used in high enough concentration to 
inhibit all bacterial growth, seem also to exercise a deleterious effect on 
the plant tissues and their enzyms. Aseptic conditions can be main¬ 
tained for respiration experiments on small amounts of plant tissue, 
but it would be very difficult to produce silage under such conditions. 
The problem attacked was therefore to differentiate as accurately as 
possible between the results of the various activities of these two kinds 
of agents. A number of different experimental methods were employed 
in the effort to arrive at a distinction between them. 
EXPERIMENTAL METHODS 
Silage made in the laboratory in glass jars has been used in the greater 
part of this work. Experimental conditions can in this way be easily 
controlled, and comparisons are thus possible. The com was chopped 
in a small silage cutter or was taken from the college farm silage cutter 
and packed as tightly as possible into cylindrical wide-mouth jars which 
were closed with rubber stoppers. Each was provided with an outlet 
tube for excess gases, which was closed with a pinchcock. Silage made 
in this manner is perfectly and normally preserved with characteristic 
appearance and aroma. Comparisons of chemical data between silage 
from the farm silos and from laboratory silos show no considerable dif¬ 
ference. Of course, no two lots of silage are ever exactly alike chemically. 
The writer has previously made both com silage and mixed silages in 
this manner (9, n). Results obtained show no evidence that this 
laboratory silage is essentially different from silage made from similar 
material in an air-tight farm silo. 
Some of the com used in this work was grown to maturity in the green¬ 
house. Both greenhouse com and field-grown com were used, to pre¬ 
vent any possible abnormal results. The greenhouse corn was generally 
nearly as good in quality as the field-grown com. 
The analytical methods used are based upon the characteristic chem¬ 
ical changes which take place in silage fermentation. The formation of 
acids and alcohols, the evolution of carbon dioxid, the disappearance of 
simple sugars, and the degradation of protein, which are the principal 
chemical phenomena of the fermentation, have been measured by the 
methods described below. Results from methods based on these chemical 
changes show, as the conventional estimations of crude protein, fiber, 
ether extract, etc. do not, the nature and extent of fermentation and the 
character of the silage, as nearly as chemical analysis can show. In 
each case comparisons were made with similar figures obtained on 
samples of the green corn from which the silage was made. In each 
case the chemical determinations were made upon the juice expressed 
