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On Spontaneous Inflammations * 
#. Fermentation of Animal and Vegetable Substances «, 
Most animal and vegetable substances, if heaped upon 
each other while they still retain their moisture, enter in- 
to fermentation ; a change is effected in their composi- 
tion, and they often beeome so much heated as to inflame. 
In this manner, haystacks, turf, flax, hemp, straw, and 
heaps of rags in paper manufactories, take fire. 
The principal precautions ought to be employed in re- 
gard to hay : if cut in a rainy season, it is generally 
stacked before it is completely dry, and in this state it 
is the more disposed to ferment and become hot. As 
soon as a stack of hay is observed to be in a state of 
fermentation, care must be taken not to throw it down too 
speedily. The exterior strata ought to be slowly detach- 
ed one after the other. When an opening is made in the 
middle of a heated mass of hay, it almost always happens 
that the fire suddenly bursts forth. 
Nothing, however, is easier than to prevent such fatal 
accidents. When it is apprehended that hay about to be 
stacked is not completely dry, it will be sufficient to strew 
over each stratum a few handfuls of muriate of soda 
(common salt). The expense in this case ought to be a 
consideration of no importance ; for the salt, by absorb- 
ing the moisture of the hay, not only prevents its ferment . 
ation, and the inflammation which thence results, but it 
adds also to the hay a savour which excites the appetite 
of the cattle, assists their digestion, and preserves them 
from a great many diseases. 
During the great heats of summer it often happens that 
heaps of dung inflame spontaneously. Great care there- 
fore must be taken to water dunghills from time to time, 
and to keep them at a certain distance from houses, both 
to prevent fires and for the sake of salubrity. 
