518 REPORT OF THE COMMISSIONER OF AGRICULTURE. 
extent. In hog cholera very extensive infiltration quite invariably 
accompanied the ulceration, so as to make the intestinal wall very 
brittle. 
In another cuse the mucous membrane appeared as if gnawed or 
eaten away in large patches. The diphtheritic deposit and subjacent 
membrane in state of necrosis had very likely been shed asaslough, — 
leaving the ragged, depressed surface. ok: 
The pathological process in the large intestine is distinctly ex- 
udative, diphtheritic in swine plague;in hog cholera it isessentially - 
necrotic or ulcerative. In the latter the virus may act not only from 
the intestine but also from the blood. In the former it perhaps 
never acts from the blood, but only from the intestine. 
The lesions of the intestinal tract are always co-existent with the 
specific broncho-pneumonia and without doubt secondary to it, be- 
cause we frequently have encountered lung disease without intestinal 
disease. The origin of the latter may be accounted for in two ways. 
The virus enters the digestive and the respiratory tract at the same 
time, or else it gains a foothold in the lungs first and thence reaches 
the intestines. This is possible, for the bronchi are filled with bac- 
teria imbedded in a largé quantity of purulent mucus, which has 
come from the diseased alveoli and bronchioles. They may be 
coughed up into the mouth and swallowed and lodge at first in the 
. mucous glands of the large intestines, where they are well protected 
while multiplying. The remainder of the mucous membrane may 
then be attacked if the animal be weak or the virus especially active. 
The simultaneous attack of lungs and large intestine is perhaps ver 
‘rare. Feeding large quantities of culture liquid and of rabbits whic 
have died after inoculation does not produce any lesions whatever. 
We must therefore consider the lungs the most vulnerable and the in-- 
testines only secondarily so. This view is supported by the fact that 
in the early and most pronounced cases of the Washington outbreak 
the intestinal lesions were very marked, but disappeared in the pro- 
gress of the disease. The virus, at first very powerful, became slowly 
attenuated, being unable to attack the mucous membrane of the in- 
testines and therefore confined to the lung tissue. Intestinal lesions 
are thus always associated with the severest lung disease, which in 
turn is characterized by an abundant muco-purulent secretion in the 
air passage. 
Diagnosis.—The disease just described can not fail to be recognized, 
as it seems to be the only severe disease of the lungs among swine of 
which we haveany knowledge. That exposure may bring on croup-’ 
ous pneumonia we do not deny ; but the character of the ordinary 
croupous pneumonia among animals is such that it can be readily 
distinguished from the irregular atypical infectious broncho-pneu- 
monia which we have just outlined. It is barely possible, however, 
that the disease may be confounded with other lesions which we have 
met now and then in post-mortem examinations. 
The small ventral lobes which hang down on either side of the 
heart are very frequently collapsed (atelectasis). The affected lobe 
is small, of a bright red, soft to the touch, but: without crepitation. 
The tissue is not diseased, as may be seen on microscopical examina- 
tion. This condition is the result of a plugging of the bronchus sup- 
plying the lobe with catarrhal products. The air can not enter the 
tube, and all the tissue supplied by if remains collapsed. Groups of 
ea permanently collapsed, may be found in other portions of the 
UNgs. 
