on the Wegetation of Seeds. ° 493 
willbe firft rarefied, as we have proved before ; 
but ‘its denfity will in a fhort time begin to in- 
creafe again from the gas emitted by the wet 
grain, as will appear if the inverted bottle be 
opened under water: for, upon removing the 
ftopper, a quantity of elaftic inflammable fluid 
will rufh -from the neck immediately, which 
will be fucceeded by a difcharge of bubbles 
of the fame kind. Hence it appears, that the 
putrefactive fermentation deftroys the vegetative 
power of feeds furrounded by azote or covered 
by water: confequently the prefence of oxygene is 
neceflary for preventing this deftructive precefs; 
which it does by producing another, that may: 
be called the vegetative fermentation. 
The reafon why one of the two kinds of fer- 
mentation in queftion always takes place, in 
feeds prepared by foaking, feems to be this: 
the water, thus introduced into their compofi- 
tion, changes that proportion of their compo- 
nent.parts, which is required to preferve them 
in a found ftate. If they be then expofed to 
the atmofphere, the action of its oxygene awakes 
the faculty of vegetation in them. On the con- 
trary, when they are furrounded by azote or 
water, which do not appear to aét on them, the 
component particles in their texture are left to 
form new combinations among themfelves, and 
are partly converted into gas; the appearance of 
which indicates the commencement of that ftage 
of 
