45
This account of the pathology of plague is based upon fifty complete
autopsies, of which twelve were examples of the pneumonic type. Sections for
the microscope of the various lymphatic glands and organs were made in twenty-
three of the cases, and from these the minute anatomy has been described.
Further, in all the cases, many specimens were prepared to show the distribution
of the plague-bacillus in the various parts of the body, and cultures were made
as well in nearly every instance. As the results obtained from cultures have
not been stated above in the post-mortem descriptions, it will be convenient to
group them together here. By the method of cultivation the plague-bacillus
has been isolated from the following organs and secretions;—from the bubo,
and, in septicæmic cases from plague glands in the various regions (e. g. in one
case from the inguinal, iliac, axillary and cervical glands) ; from the lung, liver,
spleen and kidney; from the blood and urine. In one instance the plague-
bacillus was proved by Dr. Bitter to be present in the mucus obtained from the
large intestine. In cases of plague-pneumonia the bacillus could be isolated
from the sputum daring life, from the fluid contained in the trachea and bronchi
after death, from the pneumonic patches and in several instances from the
bronchial glands.
IV.—MODE OF EXIT OF THE PLAGUE-BACILLUS FROM
THE BODY.
From consideration of the post-mortem appearances it is seen that engorge-
ment and haemorrhage are marked features of plague, and further that hæmor-
rhage is constantly found on the surface of mucous membranes ; consequently,
as soon as the bacillus has entered the blood of the general circulation, it is
possible for it to escape from the body in the hæmorrhages on mucous surfaces.
Thus in the urinary system blood may be found in the urine during life, and
after death in the tubules and pelvis of the kidney ; and, besides, there may be
extravasations on the surface of the ureter and bladder ; hence by the urine
there is a direct route for the bacillus to leave the body.
Again in the alimentary system, petechiæ are nearly always present in the
stomach, and as vomiting is a very constant symptom of plague, the bacillus
may escape in the vomit ; similarly peteohiæ are generally found in the colon
and rectum, and hence the bacillus may escape in the fæces. As for the respira-
tory system, blood may be found in the alveoli of the lungs in ordinary cases of
plague, whilst in cases of the pneumonic type it is invariably present ; besides in
these latter cases the bacillus is present in enormous numbers in the pneumonic
patches and in the sputum, and it is extremely probable that plague-pneumonia
for this reason plays an important part in spreading the disease. (In the preced-
ing section the secretions have been named from which the plague-bacillus was
isolated by the method of cultures.) With regard to the bubo itself, in certain
cases it suppurates, and it would seem possible for the bacillus to escape in the
pus ; but this was not found to be the case, for in several instances where cultures
were made from the pus, no growth of the plague-bacillus was obtained. It remains
to make a remark about the presence of the bacillus in the blood. In a number
of early plague cases which will be detailed hereafter, cultures were made
from the finger-blood, but the bacillus could not be isolated from them, in fact
they all remained sterile : whereas in fatal cases the bacillus could always be
grown from the blood after death, even when the post-mortem was made one
hour after death, and in one instance it was grown from the finger-blood twenty-
four hours before death. Hence one may say that at least in fatal cases, which
form the large majority in this disease, the bacillus is present in the blood for a
certain time before death, and is able to leave the body in the various secretions
which contain blood.
V.—MODE OF ENTRANCE OF THE PLAGUE-BACILLUS INTO
THE BODY.
Having regard to the fact that the initial bubo in plague is usually situated
in the glands of the extremities, especially the inguinal and axilliary chains, it
appears probable that the bacillus may enter the body through a lesion of the
skin—preferably of the extremities—and thence travel upwards to the nearest
B 1751—12