lty in coming to the conclusion, that the black fluid
found to such an extent in these glands in the collier and moulder, is
similar to, and a part of, that discovered infiltrated into the
substance of the lungs. If we trace the black matter in the lymphatic
vessels, (which has been done), from the pulmonary organs to the
bronchial, mediastinal, and thoracic glands, and from thence to the
thoracic duct, we cannot but admit, that it does find its way into the
venous system, and thereby contaminates the vital current.[22]

Dr Pearson of London, in his very valuable paper, published in the
Philosophical Transactions of 1813, on the coaly matter in the bronchial
glands, was convinced beyond a doubt, that it was of foreign origin, and
possessed the properties of carbon conveyed into the lungs from without.
He, at that period, was not in possession of such facts as have been
recently elicited on the subject of deleterious inhalation; but the very
interesting materials which he brought to bear on his argument, have, I
think, most satisfactorily proved the assertion which he makes, that
"the lymphatics of the lungs absorb a variety of substances, especially
this coaly matter, which they convey to the bronchial glands, and thus
render them of a black or dark-blue colour." "The texture and proportion
of the tinging matter of the glands was," he says, "different in
different subjects, whether the lungs to which they belonged were in a
healthy or diseased condition. In persons, from about 18 to 20 years of
age, some of the bronchial glands contained no tinging black matter at
all, but were of a reddish colour; others were streaked or partially
black." Again, he says, "I think the charcoal in the pulmonary organs is
introduced with the air in breathing. In the air it is suspended in
invisible small particles, derived from the burning of coal, wood, and
other inflammable materials in common life. It is admitted that the
oxygen of atmospherical air passes through the pulmonary air-vesicles or
cells into the system of blood-vessels, and it is not improbable, that
through the same channel various matters contained in the air may be
introduced. But it is highly reasonable to suppose, that the particles
of charcoal should be retained in the minutest ramifications of the
air-tubes, or even in the air-vesicles under various circumstances, to
produce the coloured appearances on the surface, and in the substance of
the lungs, as above describe