On the Chemistry of Ensilage. 
483 
possess a sufficient number of data for enabling a farmer to pro- 
duce at will either what is called " sweet " or " sour " silage of 
good keeping quality. Indeed, in a large measure, the operation 
of ensilage is conducted at present in a haphazard way, owing 
to a deficient knowledge of the principles which regulate the 
changes which green food undergoes in silos. 
Some experiments with ensilage, which I am now conducting 
personally, convince me fully of the necessity of attaching the 
highest importance to the regulation of the temperature of the 
green provender in the silos ; and in due time I hope to give an 
account of those experiments, which are now in active progress. 
Mr. George Fry has repeatedly directed attention to the 
importance of allowing green food, when first placed in a silo, 
to attain a temperature not lower than 125', and if possible 
as high as 150' F., before applying considerable pressure by 
means of weights or a layer of sand. By this rise of tempera- 
ture it passes through a process which he terms " sweet " or 
" hay " fermentation. Mr. George Fry is, to my knowledge, the 
first man who has made accurate observations pointing out the 
influence of temperature on the production of the aromatic or 
fruity smell which grass, clover, and similar green produce, 
acquire when put into a silo without any pressure beyond that 
exercised by the mass of ensilaged green food upon the lower 
layers. In my judgment, his are the only systematic and accu-. 
rate experiments which have been undertaken anywhere with 
the special object of studying the process of the heating of green 
food in the silo, and great credit is due to him for his per- 
sistent advocacy of the plan which he pursues, and which he 
considers essential for converting grass, even of an insipid and 
inferior quality, and other green fodder crops, into a very 
palatable and nutritious food which is much relished by stock 
of every description. 
As far as my present experience goes, there is a great deal in 
what Mr. Fry says with respect to the regulation and main- 
tenance of a proper temperature in the silo. From his observa- 
tions, it would appear that the too rapid exclusion of air by 
weighting the silage as soon as it is put into the silo prevents 
the green food from attaining a temperature of 125^^ F., below 
which, in his view, sweet or hay-fermentation does not take 
place, but instead either lactic or acetic fermentation. It cer- 
tainly is a fact that silage showing not more than a trace of 
acidity, and as sweet and almost as aromatic as well-made hay, 
has been made by Mr. George Fry, and could be made by 
anybody who would strictly adopt the directions which he gives 
for making sweet silage. Such silage, I find, keeps only a short 
