ase.

The flexible tube used for conveying the fume of tobacco into the
intestines, I find to be a very convenient instrument in this case, by
the method before-mentioned (only adding water to the chalk, before the
oil of vitriol is instilled, as you direct) the injection of air may be
continued at pleasure, without any other inconvenience to the patient,
than what may arise from his continuing in one position during the
operation, which scarcely deserves to be mentioned, or from the
continuance of the clyster-pipe within the anus, which is but trifling,
if it be not shaken much, or pushed against the rectum.

When I said in my letter, that fixed air appeared to be the greatest
corrector of putrefaction hitherto known, your philosophical researches
had not then made you acquainted with that most remarkably antiseptic
property of nitrous air. Since you favoured me with a view of some
astonishing proofs of this, I have conceived hopes, that this kind of
air may likewise be applied medicinally to great advantage.

W. H.

NUMBER III.

_Observations on the MEDICINAL USES of FIXED AIR. By THOMAS
PERCIVAL, M. D. Fellow of the ROYAL SOCIETY, and of the SOCIETY
of ANTIQUARIES in LONDON._

These Observations on the MEDICINAL USES OF FIXED AIR have been before
published in the Second Volume of my Essays; but are here reprinted with
considerable additions. They form a part of an experimental inquiry into
this interesting and curious branch of Physics; in which the friendship
of Dr. Priestley first engaged me, in concert with himself.

Manchester, March 16, 1774.

In a course of Experiments, which is yet unfinished, I have had frequent
opportunities of observing that FIXED AIR may in no inconsiderable
quantity be breathed without danger or uneasiness. And it is a
confirmation of this conclusion, that at Bath, where the waters
copiously exhale this mineral spirit,[15] the bathers inspire it with
impunity. At Buxton also, where the Bath is in a close vault, the
effects of such _effluvia_, if noxious, must certainly be perceived.

Encouraged by these considerations, and still more by the testimony of a
very judicious Physician at Stafford, in favour of this powerful
antiseptic remedy, I have administered fixed air in a considerable
number of cases of the PHTHISIS PULMONALIS, by directing my patients to
inspire the steams of an effervescing mixture of chalk and vinega