little else
than lamp black or soot.

It does not appear, as far as I can ascertain, that any of the
Continental physiologists are familiar with the disease now under our
consideration. Several of them, both ancient and modern, discovered
black matter in the pulmonary tissues, but not connected with nor
exhibiting the black phthisis. It is therefore unnecessary to refer to
them in general.

The following foreign authors entertain various opinions in regard to
the dark appearances in the pulmonary tissue:--

Bichat supposes the black matter in the lungs "to be owing to small
bronchial glands extending along the surface of the pleura." Breschet
believes that it is formed by the blood exhaled into the cellular
tissue, stating that its chemical composition leads him to that
conclusion. Trousseau says that it is produced by a misdirection of the
natural pigments of the body, resulting from age, climate, or disease.
Andral says, that the black appearances are the result of secretion, and
that it is more manifest as the individual advances in life. Heasinger's
opinion is, that it is analogous to pigment, and therefore he agrees
with Trousseau. Laennec was doubtful as to the real origin of black
pulmonary matter. He makes a distinction between melanotic and pulmonary
matter. He found that the melanotic matter was composed almost entirely
of albumen, while the black pulmonary matter found in the bronchial
glands contains a great quantity of carbon and hydrogen, and also that
these colouring matters have other distinguishing characters. The
melanotic matter is easily effaced by washing, while the other is
removed with difficulty. Laennec further says, that he suspected that
this pulmonary matter might arise, at least in part, from the smoke of
lamps, and other combustible bodies which are used for heat and light;
for some old men are to be met with whose lungs contain very little
black matter, and whose bronchial glands are but partially tinged with
this colour; and it has struck him that he observed this amongst
villagers who had never been accustomed to watch.[23]

Mons. Guillot, physician to the hospital for the aged at Paris, has
undertaken a series of researches in regard to the black matter found in
the lungs of old men of very considerable age. These investigations are
published in the January, February, and March numbers of the _Archives
Generales de Medecine_.[24] It is his belief that death in such cases is
owing,