I 
SPECIMENS OF PLEURO-PNEUMONIA CONTAGIOSA. 21 
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accompanied by a sero-fibrinous pleuritis ; the bronchial lymphatic 
glands are enlarged and softer than normal. The first case to 
. which I will call your attention is one of left-sided acute pneu¬ 
monia ; it involves nearly the whole of the left lung, which, as 
you will see, is greatly enlarged, weighing forty-five pounds, while 
the right lung, which is healthy, weighs but six pounds. Thus 
you will see that the diseased lung contains thirty-nine pounds of 
exudate. The pleura is covered with exudate over the affected 
lung, and there is also a very abundant exudate about the organs 
in the superior mediastinum, a complication to which I shall call 
your attention later on. On section,'this lung presents the lesions 
characteristic of the disease. This is a very typical case, and one 
upon which nobody who had ever seen even a picture of a lung in 
this disease could possibly make a mistake. The lung is solid, the 
parenchyma is hepatized, and there are varying shades of color, 
from a reddish pink to a dark red, depending upon the amount of 
blood present. The parenchyma is at the same time very moist 
(oedematous), and the interlobular tissue is filled with a jelly-like 
exudate, opaque white in appearance. This varied color of the 
parenchyma,'compared with the white opaque color of the inter¬ 
lobular exudate, gives rise to what is termed the marbling of the 
lung. Yery soon fibrous connective tissue appears in place of the 
interlobular exudate, and also around the bronchous in the center 
of the lobule. This new growdli of interlobular connective tissue 
takes place, beginning at the border of the lobule, so that between 
two lobules we have two narrow' bands of connective tissue with 
the exudate still remaining between them. The connective tissue 
may continue to grow so as to entirely fill up the interlobular 
space, or, as is more commonly the case, this takes place in some 
parts while in others the two bands separate and we have begin¬ 
ning necrosis. This separation continues in a certain direction 
and finally incloses a varying number of lobules, sometimes only 
one. When the ring is completed a sequestrum is formed and 
what we call chronic pleuro-pneiunonia is the result. The bronchi 
resist the necrotic process longest, so that it is common to see a 
necrosed mass connected by bronchi with the healthy lung-tissue. 
Finally the bronchi ulcerate through and are seen hanging from 
the wall of the cyst as fibrous prolongations; these bronchi are in 
