d."

"When I compare the black lines and black net-like figures, many of them
pentagonal, on the surface of the lungs, with the plates of the
lymphatic vessels by Cruikshank, Mascagni, and Fyffe, I found an exact
resemblance."

Dr Pearson, after various chemical experiments upon the bronchial glands
with caustic potash, muriatic and nitric acid, says, "I conceive I am
entitled to declare the black matter obtained from the bronchial glands,
and from the lungs, to be animal-charcoal in the uncombined state, _i.e._
not existing as a constituent ingredient of organized animal solids
or fluids." Dr Graham of London, in his paper on this subject, recorded
in the 42d vol. of the _Edinburgh Medical and Surgical Journal_, gives
the following opinion, as the result of a series of investigations, with
the view of determining the nature of the disease in question. He says,
I have had several opportunities of substantiating the carbonaceous
matter in a state of extraordinary accumulation in black lungs supplied
by my medical friends. The black powder, as derived from the lungs,
(after an analysis,) is unquestionably charcoal, and the gaseous
products from heated air, result from a little water and nitric acid
being retained persistently by the charcoal, notwithstanding the
repeated washing, but which re-acting on the charcoal at a high
temperature, coming off in a state of decomposition. In regard to
another analysis of a lung, he says, "The carbonaceous matter of the
lung cannot therefore be supposed to be coal, altered by the different
chemical processes to which it has been submitted in separating it from
the animal matter. The carbonaceous matter of this lung, appears rather
to be lamp black."

From the whole results, I am disposed to draw the following
conclusions:--

_1st_, The black matter found in the lungs is not a secretion, but
comes from without. The _pigmentum nigrum_ of the ox I find to lose its
colour entirely, and to leave only a quantity of white flocks, when
rubbed in a mortar with chlorine water. Sepia, which is a preparation of
the dark-coloured liquor of the cuttle fish, was also bleached by
chlorine, but the black matter of the lungs was not destroyed or
bleached in the slightest degree by chlorine, it even survived
unimpaired the destruction of the lungs by putrefaction in air.

_2d_, This foreign matter probably varies in composition in different
lungs, but in the cases actually examined, it seems to be