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A number of experiments were made which were designed to 
demonstrate, if possible, the specifie nature of the bacteria obtained 
from diseased lungs. A reproduction of the disease after the intro- 
duction of the bacteria contained in pure cultures into the lung tis- 
sue itself must be regarded as conclusive evidence. 
The following means of infection were tried: 
(a) By exposing pigs to a spray of culture liquid.—Webruary 17 
- Nos. 398, 400 were placed in a tight box, 3 by 4 by 2 feet, witha 
glass top. A spray was allowed to play into the box from an atom- 
izer, the nozzle of which was introduced through a small hole in the 
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side near the top of the box. The spray thus played across the top | 
of the box, and was continued for two hours on two consecutive 
days, 300° of culture liquid being used each time. The culture 
was an infusion of beef, in which the swine plague bacteria (from an 
Iowa outbreak) had multiplied at 95° F. for two days. For several 
days after respiration was somewhat labored, and for nearly a week 
they ate very little. Subsequently, however, they fully recovered. 
Nos. 393, 394 were exposed March 3 to a spray in the mariner de- 
scribed. The culture was made in beef infusion and was one day 
old. Theswine plague bacteria were from the Washington outbreak. 
The spraying was continued for one and one-fourth hours, several 
hundred cubic cemtimeters (about one-half pint) being used. No 
symptoms of lung disease followed the spraying. No. 393 was killed 
April 28, nearly two months later, and found perfectly sound. No. 
394 was exposed to hog cholera April 30, and died of the acute hemor- 
rhagic form of this disease May 17, The lungs were not hepatized but 
dotted with numerous subpleural petechize, characteristic of acute 
hog cholera. 
Spraying and feeding cultures both had thus far proved ineffectual 
in reproducing any lesionsin the lungs or the intestinal tracts. Other 
modes of introducing the virus were therefore tried. 
(b) Two pigs (Nos. 383, 385), one of which had been fed with hog 
cholera and the other with swine plague cultures December 19, 1886, 
were perfectly well March 16, on which day 5° of a liquid eulture 
of swine plague bacteria was injected into the trachea of each. Owin 
to the thick layers of fat in the neck, intratracheal injection cotild 
only be practiced by cutting down to the trachea, raising it with the 
finger, and then introducing the needle of the hypodermic syringe. 
After the operation the animals were dull and refused feed for one ° 
or two days; after that they were fairly well. The incisions mean- 
while hénted up. April 28, nearly one and one-half months after the 
inoculation, No. 385 was killed. The organs were normal; no lung 
disease manifest. No. 383 was exposed to hog cholera in an infected 
ht April 19, more than a month after the tracheal injection. It had 
een apparently well during this time. It died May 11 of acute 
hemorrhagic cholera. The autopsy notes being recorded elsewhere, 
it suffices to state that the lungs were covered, as is common in this 
disease, with large subpleural ecchymoses, There was no hepatiza- 
tion suggesting swine plague. On April 4 two pigs (Nos. 389, 401) re- 
ceived into the trachea each 5° of A beet infusion culture of swine 
plague bacteria about two days old. On the following day both were 
well. On April 27 No. 389 was killed and found healthy. No. 401, 
killed April 28, had likewise remained unaffected by the inoculation. 
