reaking down. The inflammatory irritation
which the growth of the tubercles on the surface of the lungs arouses gives
rise to adhesion of the lungs to the ribs and diaphragm. This adhesion is
sometimes so firm and extensive that the lungs appear grown to the chest
wall.

When, therefore, the lungs in advanced stages of the disease are cut open
we observe large yellowish masses, from one-quarter to three-quarters of an
inch in diameter, of a cheesy texture, in which calcified, gritty particles
are embedded and which are surrounded by very firm connective tissue. The
neighboring lung tissue, when collapsed and involved in bronchopneumonia,
has the color and consistency of pale-red flesh. The air tubes, large and
small, stand out prominently on the cut surface. They are distended with a
pasty, yellowish, cheesy mass, surrounded and enveloped in thick mucus, and
their walls greatly thickened. The larger bronchi may be sacculated, owing
to the distention produced by the cheesy contents.

The disease usually attacks the bronchial glands, which are situated on the
trachea and bronchial tubes at the bifurcation. The changes in the glands
are the same as those going on in the lung tissue, and they frequently
reach an enormous size.

The tubercle formation on the serous membranes covering the lungs and chest
wall (Pl. XXXVII, fig. 2), which may go on at the same time with the lung
disease or independent of it, has been called "pearly disease," on account
of the peculiar appearance of the tubercles. These begin as very minute,
grayish nodules, which give the originally smooth, lustrous membrane a
roughened appearance. These minute tubercles enlarge, become confluent, and
project above the surface of the membrane as wartlike masses, attaining the
size of peas. In this stage their attachment to the membrane is by means of
delicate fibers. The attachment is loose, so that the tubercle hangs by a
short pedicle or neck and may be moved slightly to and fro. Large masses
are frequently formed by a coalescence of many tubercles and the secondary
formation of the same. These may be found on the lungs, the ribs, and the
diaphragm. These tubercles likewise undergo degenerative changes. The
center partly softens and partly calcifies into a grayish mortarlike mass,
and is gritty. Associated with the formation of tubercles on the pleura,
those glands situated back of the center of the lungs between the two main
lobes (posterior mediastinal) be