tter. Between the age of seventy and a
hundred, the lungs are generally infiltrated with fluid black matter,
which can be expressed from the cut surfaces, and stain the hands
black."

"There are many circumstances which favour the accumulation of this
black matter in the lungs; for instance, long-continued living in a
smoky atmosphere, like that of this city, the inhalation of coal-dust,
as in the case of colliers, or of charcoal-powder, as in the case of
iron-founders. There can be no doubt that we inhale foreign substances
along with the atmospheric air.

"We find the mucus which has remained in the nostrils for some time to
be of a dark colour, and if we examine it with a microscope, we find,
that this is owing to the presence of small particles of dust or other
foreign substances, which the air may have accidentally contained. The
mucus first coughed up from the lungs in the morning, is of a dark
colour from the same cause, and the facts now maintained prove, that
foreign substances suspended in minute particles in the atmosphere, may
be inhaled into the lungs. I believe in all the extreme cases which have
occurred in colliers and moulders, that there must have existed some
previous disease of the lungs which prevented the foreign matter from
being thrown off." "According to the views which we have taken of the
subject, there are only two ways by which black matters may be deposited
in the lungs; first, by a morbid secretion; second, by a foreign
substance inhaled with the atmosphere. The former is a rare disease,
while the latter is very common. I am inclined to think that the true
melanosis generally occurs in the form of rounded tumours, which, when
cut in two, present a uniform black colour without any trace of
air-cells, while in the spurious melanosis the deposition is general,
and black matter flows freely out when the cut surfaces are pressed. At
first the lung is crepitous, and swims in water; but as the black matter
increases, it becomes solid, and, as in the case of colliers who die of
this disease, resembles a piece of wet peat in point of consistence. It
is only in the cases of colliers, moulders, or others who inhale great
quantities of black matter, that the lungs are rendered perfectly
solid."

There is an exceedingly interesting and valuable paper, written by Dr
Brockmann of Clausthal, upon the pulmonary diseases of a certain class
of German miners,--supposed to be in the Hartz mountains,--in
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