tion of the blood, I leave to others to
ascertain. The attraction which the blood has for phlogiston cannot be
so strong as that with which plants and insects attract it from the air,
and then the blood cannot convert air into aerial acid; still it becomes
converted into an air which lies midway between fire-air and aerial
acid, that is, a vitiated air; for it unites neither with lime nor with
water after the manner of fire-air and it extinguishes fire, after that
of aerial acid. But that the blood really attracts the inflammable
substance I have additional experiment to prove, since I have removed
phlogiston by help of my lungs from inflammable air, and have converted
this into vitiated air.

I filled a bladder with the air which one obtains from iron filings and
vitriolic acid (Sec. 30, _c._), and respired it in the manner previously
described (Sec. 84). I was only able to inhale it 20 times, and after I had
somewhat recovered, I expelled the air once more from my lungs as
completely as possible, and again inhaled this inflammable air: after 10
inhalations I was compelled to desist from it, and observed that it
could no longer be kindled, and also would not unite with lime water.
In one word it was a vitiated air.

I kept a piece of sulphur in continuous ebullition over the fire in a
retort, capable of holding 12 ounces of water, with an empty bladder
attached in place of a receiver, the retort also placed so that the
sulphur which rose into the neck could run back again. After all had
become cold, I found the air neither increased nor diminished: it smelt
slightly hepatic, and extinguished a burning candle. I shall prove
further on that sulphur can unite with more phlogiston; and it seems to
me to follow from this experiment that something inflammable from the
air had deposited itself upon the sulphur, and that the air had thereby
acquired the property of a vitiated air. It is, however, also remarkable
that other bodies which attract the inflammable substance more strongly,
as for example, the fuming acid of nitre, do not abstract it from the
air. It is likewise strange that I was able to inhale the inflammable
air into my lungs only 20 times; and I observe here as something
peculiar that, if I mistake not, I became very warm a quarter of an hour
afterwards. It is also to be observed that fire-air, vitiated by the
lungs, extinguishes fire; why does not the aerial acid attract the
phlogiston again? why not also the v