Report on the Pathological Anatomy of Pleuro-pneumonia. 191 
injection mass. The course and relations of the larger channels 
may be thus easily followed with the naked eye. The clear 
transparent fluid exudation which occurs between the lobules in 
the more extended part of the lung lesion is not often met with 
about the bronchi. I am led to suppose from this that the 
exudation is more dense from the first in this region, or that it 
becomes solid at an early date after its commencement. 
The delicate fibrous tissue, which forms the bed of the lym- 
phatics around the bronchus, seems to undergo a slow process of 
thickening ; the elements of the tissue rapidly proliferating. In 
the very advanced stages, where the fibroid change has had time 
to occur in the lung, the tissue proliferation attains a maximum, 
and, as already mentioned, may cause the occlusion of tubes of 
considerable calibre. 
The microscopic examination of the plug which fills the 
bronchi of the diseased part shows that it is made up of amorphous 
or finely granular material, and of a great variety of elements, in 
varying quantities and different stages of destruction. Among 
these are found quantities of columnar epithelium cells, all of 
which are granular, and may be broken. On some of them cilia 
may still be recognised. There are also great numbers of large 
indefinite granular cells which contain a distinct nucleus. Blood- 
cells and discs are also found, in some cases the quantity being 
enormous. Besides these elements are numerous threads of 
fibrin, and many foreign elements, such as fungi, bacteria, &c. 
For some distance along all the tubes in the neighbourhood of 
the disease the epithelium is greatly changed. Even in those 
bronchi whose coats are hardly, if at all, altered, the epithelial 
cells are granular and easily rubbed off the membrane, so that it 
is almost impossible to make a preparation where they remain 
in situ. In the part where the lung tissue is solid, there is never 
any epithelial lining to the tubes. The elements of the tissue 
forming the thickened bronchial wall are found to be pushed 
asunder by exudation and numerous young cells. The fibril- 
lation of the white fibrous tissue is clouded and obscured, and 
thick bundles of strong elastic fibres stand out boldly, as if the 
tissue had been treated with acetic acid. The muscular part of 
the wall is very indistinct. The plates of cartilage are unaltered, 
but are separated from each other, and seem very far removed 
from the cavity of the tube, considerable exudation having been 
poured into the submucous tissue. 
By making a series of transverse sections, or a longitudinal 
section, of the bronchial wall, in one of the least developed 
foci of disease, one can see that the disease of the mucous 
membrane extends to a greater distance from the diseased centre 
than that of the bronchial wall or of the peribronchial tissue. 
