36
all their anatomical features are distinct. All the blood-vessels in the gland
are distended with blood-corpuscles, and at parts haemorrhage has occurred into
the gland-substance, which is most frequently seen beneath the capsule, but
may also be at other parts. The lymphatic vessels and lymph channels in the
gland are wide and distended with lymph-corpuscles. The distension of the
blood and lymph vessels is always most marked at the hilus, and there may be
hemorrhages into the areolar tissue here. In some glands small areas may be
seen, where softening and breaking down is taking place, granular debris and
broken-down cells being seen here. The glands shew these changes in varying
degree; in some there is merely slight engorgement with some distension of
lymph-vessels, in others there is wide distension of both kinds of vessels, with
some amount of haemorrhage into the gland tissue ; whilst in others again there
are many hasmorrhagic areas which may occupy half or more of the gland, and
it is in these glands that breaking down is usually seen. In a septiaemic case
the glands, which have not the characteristic plague appearance, shew under the
microscope either slight engorgement or normal features.
With regard to the remaining organs the appearances described under the
bubonic form apply also to the septiaemic form of plague,
C.—THE PNEUMONIC FORM.
A section of lung-tissue, apart from a pneumonic area, shows great engorge-
ment of all large blood-vessels, and of the alveolar capillaries as well, and
patches of haemorrhage into the alveoli around these engorged vessels are seen
scattered about. In a pneumonic area three zones can be made out. At the
circumference there is intense engorgement of all vessels including alveolar
capillaries, the alveoli are full of blood, and the heemorrhage is so intense that
many of the alveolar septa are broken down, entirely absent, or represented by
mere shreds. Within the circumference is seen a zone in which the alveoli are
intact and are completely filled with well-stained cells, so that there is no interval
between the alveolar walls and their contents ; and at the centre is one universal
mass of similar cells, and the cellular infiltration is so extreme that the walls of
the alveoli are scarcely visible. Such is the general arrangement of the pneu-
monic patch, although there many be alveolar haemorrhage in parts of either the
middle or central zone.
Under a higher power the alveoli of the circumference are seen to be com-
pletely filled with blood-corpuscles, and there is scarcely any appearance of
fibrin, or none at all ; in the middle zone the alveolar contents consist for the
most part of catarrhal epithelium with some white and a few red blood-corpus
cles, and a little fibrin or none at all, whilst the dense central mass of cells
consist of catarrhal epithelium and leucoceptes with some granular debris.
Thus the pneumonic area has the appearance of very extreme lobular or
catarrhal pneumonic.
The walls of the bronchial tubes, as well as of the large veins, show great
engorgeaient, and there are haemorrhages into the vein-walls. Blood and
catarrhal cells may be seen in the finer bronchi, but the bronchial mucous
membrane is scarcely altered, there being at most a little cellular proliferation.
There are the appearances of acute pleurisy over those pneumonic areas which
project upon the surface of the lung, with hemorrhages beneath the pleura.
The bronchial glands show engorgement of blood-vessels, some hemorrhage
into the gland tissue and distended lymphatic vessels ; but in some cases these
conditions are only slightly marked and the glands looked nearly normal. The
remaining lymphatic glands in the body looked either normal, or presented the
characters described above to a slight extent.
With regard to the other organs, the description given under the bubonic
form, of plague applies here also, except that generally engorgement and
haemorrhage are less marked.
D.—THE PLAGUE BACILLUS IN SITU.
Sections of the various organs and lymphatic glands were prepared to show
the plague bacillus in situ; they showed best when stained with Löffler's methy-
lène blue or carbol-fuchsin, but they could not be demonstrated with Gram's
method.