is as
noxious as any whatever, a mouse dying the moment it is put into it; but
frogs and snails (and therefore, probably, other animals whose
respiration is not frequent) will bear being exposed to it a
considerable time, though they die at length. A frog put into nitrous
air struggled much for two or three minutes, and moved now and then for
a quarter of an hour, after which it was taken out, but did not recover.
_Wasps_ always died the moment they were put into the nitrous air. I
could never observe that they made the least motion in it, nor could
they be recovered to life afterwards. This was also the case in general
with _spiders_, _flies_, and _butterflies_. Sometimes, however, spiders
would recover after being exposed about a minute to this kind of air.

Considering how fatal nitrous air is to insects, and likewise its great
antiseptic power, I conceived that considerable use might be made of it
in medicine, especially in the form of _clysters_, in which fixed air
had been applied with some success; and in order to try whether the
bowels of an animal would bear the injection of it, I contrived, with
the help of Mr. Hey, to convey a quantity of it up the anus of a dog.
But he gave manifest signs of uneasiness, as long as he retained it,
which was a considerable time, though in a few hours afterwards he was
as lively as ever, and seemed to have suffered nothing from the
operation.

Perhaps if nitrous air was diluted either with common air, or fixed air,
the bowels might bear it better, and still it might be destructive to
_worms_ of all kinds, and be of use to check or correct putrefaction in
the intestinal canal, or other parts of the system. I repeat it once
more that, being no physician, I run no risk by such proposals as these;
and I cannot help flattering myself that, in time, very great medicinal
use will be made of the application of these different kinds of air to
the animal system. Let ingenious physicians attend to this subject, and
endeavour to lay hold of the new _handle_ which is now presented them,
before it be seized by rash empiricks; who, by an indiscriminate and
injudicious application, often ruin the credit of things and processes
which might otherwise make an useful addition to the _materia_ and _ars
medica_.

In the first publication of my papers, having experienced the remarkable
antiseptic power of nitrous air, I proposed an attempt to preserve
anatomical preparations, &c. by means of it;