[ I 9 I ] 
either itfelf extinguifh flame, or has in it fuch a mix- 
ture of fixed air, as to give it that property. 
That the putrid effluvium will mix with water 
feems to be evident from the following experiment. 
If a moufe be put into a jar full of water, flanding 
with its mouth inverted in another veflel of water, a 
confiderable quantity of elaftic matter (and which 
may, therefore, be called air) will foon be generated, 
unlefs the weather be fo cold as to check all putre- 
faftion. After a fhort time, the water contracts an 
extremely fetid and offenfive fmell, which feems to 
indicate that the putrid effluvium pervades the water, , 
and affeds the neighbouring air ; and fince, after this, 
there is often no increafe of the air, that feems to be 
the very fubftance which is carried off through the 
water, as fall; as it is generated ; and the offenfive 
fmell is a fufficient proof that it is not fixed air. For 
this has a very agreeable flavour, whether it be pro- 
duced by fermentation, or extraded from chalk by 
oil of vitriol ; affeding not only the mouth, but 
even the noftrils, with a pungency which is pe- 
culiarly pieafing to a certain degree, as any perfon 
may eafily fatisfy hirtifelf who will chufe to make 
the experiment, if the water in which the moufe 
was immerfed, and which is faturated with the pu- 
trid air, be changed, the greater part of the putrid . 
air will, in a day or two, be nbfqrbed, though the 
moufe continues to yield the putrid effluvium as be- 
fore ; for as foon as this frefh water becomes faturated . 
with it, it begins* to be offenfive to the fmell, and 
the quantity of the putrid air upon its furface increa- 
ies as before. I kept a moufe producing putrid fir in 
this manner for the fpace of feveral. months, . 
Sixx 
v. ' 
