buried with the fodder as it is packed in the silo, and the exclusion of the atmosphere, as Pasteur has proved, is a condition that favors fermentation, the oxygen itself not being directly concerned in the process. When the greatest care is taken in packing the ensilage, the temperature of the mass will often rise above 100° Fahr. (I have observed a temperature of 105° under such conditions); and, when the time of filling is extended over several days, a considerably higher temperature may be developed.
There are good reasons for the belief that, with less packing of the fodder when put in the silo, the time of filling may be safely extended until the temperature rises to a point that is fatal to the bacteria, and this is the probable explanation of the reported cases in which the ensilage is said to be "sweet," or free from acidity.
The efficient cause of this preliminary heating process, or the changes in the fodder involved in its development, have not been determined by experiment, and we do not know the precise conditions under which the best results may be obtained.
In the present state of our knowledge of the subject, the most desirable method may be to fill the silo without any packing, beyond that produced by the weight of the superincumbent mass, and then allow it to remain until the desired temperature is reached, before putting on the cover and weights. The best method can only be determined by carefully conducted experiments, that are made with a full knowledge of the different conditions that may have an influence in modifying the results. It can not, however, be doubted that sour ensilage can only be produced by conducting the process so that the temperature does not rise above the point that is fatal to the bacteria (probably 115° to 120°).
Observations on temperature have been generally neglected when silos were filled, and we, therefore, lack the necessary data for determining the precise temperature required to prevent fermentation, or the most favorable conditions for producing it, from the results of practical experience.
Several cases have been reported to me in which the fodder at the time of filling the silo was supposed to be "spoiled" from the high temperature developed before it was covered and weighted, but on opening these silos, after several months, the result uniformly obtained was ensilage of the best quality, free from acidity. But a single case has, however, come to my knowledge, in which the exact temperature was recorded at the time of filling the silo, when the resulting product was sweet ensilage. Mr. George Fry, of England, reports the results of his experience the past season, which is of particular interest in connection with my experiments with ensilage. He filled a silo with Trifolium incarnatum (crimson clover), "rough grass," and "clover and rye grass," between the 7th and 30th of June, the temperature recorded at the time of covering being 132° six feet from the
