230 ALCOHOL, VINEGAR, SAUER KRAUT, TOBACCO, SILAGE, FLAX. 
The extent of this rise is dependent upon the amount of oxygen 
present and the readiness with which the heat is radiated. The 
temperature should not rise above 150 F., and, to give the best 
result, it should be much lower. The proper production of silage, 
however, does not appear to be dependent upon this rise in tempera- 
ture, inasmuch as perfectly normal silage may be made in small 
vessels where hardly any rise in temperature is noticeable. 
This high temperature lasts a few days and then the mass slowly 
cools. The production of heat appears to be very rapid for a few 
days, and then somewhat quickly declines; but a less rapid evolution 
of heat continues for a long time, perhaps several weeks. After 
the reduction in temperature other changes begin, which are much 
slower, and after several weeks the character of the material is 
found to be greatly changed. This is a secondary fermentation. 
of a different type. It develops a certain amount of acid, its chemical 
nature is altered, and it develops a new flavor and aroma which should 
be distinctly aromatic, without any signs of putrefaction or mustiness. 
There is found to be a considerable loss of material, a loss ranging 
from 4 per cent, to 40 per cent. This is a very wide range, and 
shows that the method of ensilage has an extraordinary effect upon 
the product obtained. The loss is chiefly a loss of carbohydrates, 
although there is also an appreciable loss of albuminoids. The 
loss is largely parallel to the amount of oxygen that finds its way 
into the silo, being very slight if the oxygen of the air be thoroughly 
excluded. Perfect exclusion of air is, then, the best means of 
preventing the loss. 
In a properly prepared silo the fermentative changes do not ex- 
tend beyond this, and the material will now remain sweet for 
months. The superficial layers may become decayed and ruined, 
but the central mass itself is not affected. After the feeding from a 
silo is commenced its contents must be used up somewhat rapidly, 
for various undesirable fermentative changes may set up in the 
superficial layers as they are successively exposed to the air. 
The Causes of Ensilage Fermentation. Three different 
factors have been suggested as causes for the fermentations inside 
the silo. These are: i. The action of bacteria. 2. Respiratory 
