n nodes on
the tibia; or by other matter derived to the bone in malignant fevers; and
is not confined to the ends of them.

The separation of the dead bone from the living is a work of some time. See
Sect. XXXIII. 3. 1.

* * * * *

ORDO I.

_Increased Sensation._

GENUS V.

_With the Production of new Vessels by external Membranes or Glands,
without Fever._

The ulcers, or eruptions, which are formed on the external skin, or on the
mouth or throat, or on the air-cells of the lungs, or on the intestines,
all of which are more or less exposed to the contact of the atmospheric
air, which we breathe, and which in some proportion we swallow with our
food and saliva; or to the contact of the inflammable air, or hydrogen,
which is set at liberty by the putrefying aliment in the intestines, or by
putrefying matter in large abscesses; all of them produce contagious
matter; which, on being inoculated into the skin of another person, will
produce fever, or a similar disease.

In some cases even the matter formed beneath the skin becomes in some
degree contagious, at least so much so as to produce fever of the hectic or
malignant kind, as soon as it has pierced through the skin, and has thus
gained access to some kind of air; as the fresh puss of a common abscess;
or the putrid pus of an abscess, which has been long confined; or of
cancerous ulcers.

From this analogy there is reason to suspect, that the matter of all
contagious diseases, whether with or without fever, is not infectious till
it has acquired something from the air; which, by oxygenating the secreted
matter, may probably produce a new acid. And secondly, that in hectic fever
a part of the purulent matter is absorbed; or acts on the surface of the
ulcer; as variolous matter affects the inoculated part of the arm. And that
hectic fever is therefore caused by the matter of an open ulcer; and not by
the sensation in the ulcer independent of the aerated pus, which lies on
it. Which may account for the venereal matter from buboes not giving the
infection, according to the experiments of the late Mr. Hunter, and for
some other phenomena of contagion. See Variola discreta, Class II. 1. 3. 9.

SPECIES.

1. _Gonorrhoea venerea._ A pus-like contagious material discharged from the
urethra after impure cohabitation, with smarting or heat on making water;
which begins at the external extremity of the urethra, to which the
contagious ma