d a very large proportion of
carbon, while of the contents of the melanotic cyst, the same process
did not leave a vestige of colouring matter,--evidently proving the
distinction which exists between those two dark deposits, and making it
sufficiently obvious, that melanotic matter is composed of the
constituent elements of the blood, and has its origin within the body.
There cannot remain a doubt as to the nature of the chimney sweeper's
case; for, from the knowledge which we have of his occupation, and from
the chemical properties manifest after investigation, I think I am
entitled to declare the black matter obtained from the bronchial glands
to be carbon inhaled with the air during his labour, and not existing as
a constituent ingredient of organized solids or fluids.

The microscopic examination showed the carbon most distinctly in a
molecular form.

It is my intention to return to this subject at a future time.

NORTHUMBERLAND STREET, EDINBURGH,
January 1846.

* * * * *

FOOTNOTES:

[1] Vide an admirable series of papers on this subject in the volume of
this Journal for 1843, by Dr Calvert Holland.

[2] About ten miles east from Edinburgh.

[3] Generated from the decay of vegetable and other substances in the
_formerly wrought_ pits, which communicate with those at present in use.

[4] It is proved, from the difference in the chemical character
possessed by the melanotic matter, as compared with the matter found in
the lungs of miners.

[5] It will be observed, that, though the small blood vessels are
destroyed, no hemorrhage takes place, owing to the formation of a
carbonaceous plug.

[6] The air of the coal-pit is so charged with carbon as to prevent the
collier from distinguishing his neighbour when at work.

[7] Note from the evidence of a collier examined before the Government
Commissioners in 1842, No. 147 of Report. "Colliers in this part of the
country are subject to many oppressions; first, Black spit, which
attacks the men as soon as they get the length of 30 years of age;"
second, Note 150, "The want of proper ventilation in the pit is the
chief cause, and no part requires more looking after than East Lothian,"
the men die off like rotten sheep. Note, 153, the witness, 32 years old,
says, "I am unable to labour much now, as I am fashed with bad
breathing--the air below is very bad, and till lately no ventilation
existed."

[8] The black sputum ret