tion, are usually found in the peritoneal cavity of chronic cases. 
; Lung lesions.—This epizootic was studied mainly for the purpose 
of determining the condition of the lungs in hog cholera. Weshall 
-see in the following article that swine plague is essentially a disease 
of the lungs, secondarily of the digestive tract. lt may be possible 
to find some cases of swine plague in which the large intestines are 
rimarily diseased. Thus far they have not come to our notice. 
om the facts obtained from this epizootic we may safely assume 
that hog cholera produces no lesions which may not be found in the 
lungs of apparently healthy animals. In other words, the lesions 
. which we find there have nothing to do with hog cholera. We must 
except, however, the hemorrhages found in a small percentage of 
-. ceases. Such are co-existent with hemorrhages in most other organs, 
and are not specific lung lesions. The lesions found on post-mortem 
examination were either simple collapse or lobular broncho-pneu- 
monia following it. yee 
Simple collapse usually involved the two ventral dependent lobes,* 
-, more rarely portions of thé small cephalic and the principal lobes. 
The collapsed lobes, or groups of lobules interspersed among em- 
_ physematus lobules, appeared slightly if at all depressed. The color 
Beerecbed that of muscular tissue. In only a few instances could 
plugs be found occluding the bronchus. 
Sections made from lobules in this condition show a number of 
interesting features. The alveolar walls are crowded together in 
some places till they almost touch one another. 
Besides the fibrine there may or may not be one or several large 
cells, round, with much protoplasm inclosing a vesicular nucleus. 
The bronchi are all patent, the epithelium intact. The alveolar 
walls are not changed, nor is there any round ceil infiltration to_be 
seen. In circumscribed areas the capillary net-work is distended 
with blood corpuscles, while all the larger vessels are similarly filled 
with these elements. 
In the alveolar ducts there is now and then considerable fibrillar 
fibrine well brought out by Weigert’s stain. 
In about 15 per cent. of the animals examined one of the smaller 
ventral lobes was airless throughout, moderately enlarged. Viewed 
from the surface the diseased lobe is bright red, dotted with minute 
pale grayish or yellowish points of a diffuse hazy outline, each not 
more than 1™™ in diameter. They are usually arranged in groups of 
four and represent the ultimate air cells filled with cellular exudate. 
The larger bronchi are also occluded. The exudate is yellowish 
white, so firm that it is possible to tear away the lung tissue with 
needles without necessarily breaking up the inclosed exudate. It 
may thus be teased out in the form of branching cylinders, becom- 
ing smaller and finally dwindling down to the size of a coarse hair. 
Microscopic sections reveal a broncho-pneumonia. The alveolar 
walls are beset with distended capillaries. The alveoli are filled up 
with cellular masses, fibrine appearing very rarely. In most alveoli 
_ the cells are large, round, with vesicular nucleus, evidently derived 
~. from the alveolar epithelium. In some alveoli and in the smallest 
air tubes the cell mass is so dense that individual elements can only 
be seen with dfficulty. But they appear to be identical with the 
cells just described. “The process seems to be accompanied with very 
* See p. 518 for nomenclature of lobes of pig’s lung. 
¥ 
Bt i 
a ed Oe oie yy aie ” 4 I 1, : Miche i: . ‘. ) op ‘ 
‘BUREAU OF ANIMAL INDUSTRY. 485 — 
ethe ulcerations. In fact, cocci, closely resembling those of suppura- 
