njurious
material. This cancerous matter is absorbed, and induces swelling of the
neighbouring lymphatic glands; which also become schirrous, and afterwards
cancerous.

This cancerous matter does not seem to acquire its malignant or contagious
quality, till the cancer becomes an open ulcer; and the matter secreted in
it is thus exposed to the air. Then it evidently becomes contagious,
because it not only produces hectic fever, like common matter in ulcers
open to the air; but it also, as it becomes absorbed, swells the lymphatic
glands in its vicinity; as those of the axilla, when the open cancer is on
the breast. See Class II. 1. 3.

Hence exsection before the cancer is open is generally a cure; but after
the matter has been exposed to the air, it is seldom of service; as the
neighbouring lymphatic glands are already infected. I have observed some of
these patients after the operation to have had diseased livers, which might
either have previously existed, or have been produced by the fear or
anxiety attending the operation.

Erosion with arsenic, after the cancer is become an open ulcer, has
generally no better effect than exsection, but has been successful before
ulceration. The best manner of using arsenic, is by mixing one grain with a
dram of lapis calaminaris, and strewing on the cancer some of the powder
every day, till the whole is destroyed.

Cancers on the face are said to arise from the periosteum, and that unless
this be destroyed by the knife, or by caustics, the cancer certainly
recurs. After the cancer becomes an open ulcer of some extent, a purulent
fever supervenes, as from other open ulcers, and gradually destroys the
patient. See Class II. 1. 6. 13.

Two very interesting cases have been lately published by Dr. Ewart, of
Bath, in which carbonic acid gas, or fixed air, was kept constantly in
contact with the open cancerous ulcers of the breast; which then healed
like other common ulcers. This is rather to be ascribed to the exclusion of
oxygen, than to any specific virtue in the carbonic acid. As in common
ulcers the matter does not induce hectic fever, till it has been exposed to
the air, and then probably united with oxygen.

The manner of applying the fixed air, is by including the cancer in one
half or hemisphere of a large bladder; the edges are made to adhere to the
skin by adhesive plaster, or perhaps a mixture of one part of honey with
about twenty parts of carpenter's glue might better s