Mar. 6 ,1917 
Fermentation of Corn Silage 
367 
rate of change increases with the increase in number of organisms, and 
the resulting curve is convex toward the X axis. Then there is a point 
of inflection, after which the curve becomes similar to the enzymic curve. 
An example of a curve of this type is shown in figure i, a typical “fer¬ 
mentation curve.” There is always a point of inflection, or change in 
direction of curvature in a bacterial curve, provided the data begin before 
the number of organisms has reached its maximum. These two kinds 
of curves are discussed at some length by Rahn in the article cited (16). 
In natural or mixed fermentations, such as the formation of silage, it 
is possible that different processes taking place at the same time will 
destroy the natural form of the curve. Or if both chemical and bio¬ 
logical factors are present and producing the same substance, e. g., alco¬ 
hol, the nature of the curve might be variable, depending upon the rela¬ 
tive “active mass” of the two agents. In the case of so large an inocu¬ 
lation that the bacteria 
do not multiply mate¬ 
rially, a bacterial curve 
might possibly resem¬ 
ble the curve of an 
enzymatic process. 
However, the chemical 
composition of the ma¬ 
terial and the extent of 
the fermentation de¬ 
pend upon many vari¬ 
able factors, such as 
soil and meteorological 
conditions, the method 
and rate of filling the 
silo, and opportunity for inoculation. The silage resulting is thus a vari¬ 
able product, depending on these and other factors. Therefore it seems 
very unlikely that any considerable error in the interpretation of curves 
drawn from silage data would persist through a number of entirely separate 
experiments. This is evident from the data given in the following pages. 
The analytical methods outlined above were used to obtain data on the 
chemical changes occurring during the early period of silage fermenta¬ 
tion, in order that curves such as just described might be plotted. The 
data obtained by Neidig (14) on this part of the fermentation process indi¬ 
cate the impossibility of obtaining regular curves and strictly comparable 
results by taking samples from a farm silo, owing to the variability in 
composition of the silage in different parts of the silo, and the necessity 
of the perfect exclusion of air throughout the process. Therefore, 
silage was made in the laboratory in small jars as mentioned above. 
The chopped corn was very thoroughly mixed, and after a sample 
had been taken for the initial analysis, it was packed tightly into jars. 
AGE OF SILAGE - OAYS 
Fig. i.—C urve showing the disappearance of sugars in series i. 
