66 IN RABBITS 



Second degree of resistance — pleuritis and pericarditis. — Rab- 

 bit No. 38 was treated before inoculation with 4.5 cc. of a steril- 

 ized suspension of agar cultures of swine-plague bacteria in 3 

 doses. Together with a control rabbit, it received under the 

 skin the equivalent of o.ooi cc. of a fresh bouillon culture of 

 swine-plague bacteria. The control died in twenty hours. The 

 treated rabbit died six days after inoculation. At the point of 

 inoculation there was a purulent infiltration of the subcutis 3 

 cm. in diameter. The abdomen and abdominal viscera were 

 free from macroscopic changes. In the thorax, the pleural 

 cavity was lined with a grayish, friable exudate consisting of 

 round cells and bacteria. Lungs hyperaemic and only partly 

 collapsed. Pericardium also covered with a slight exudate. 



Third degree of resistance — pleuritis {pericarditis) and peri- 

 tonitis. — Rabbit No. 15 received in the ear vein 12 cc. of a ster- 

 ilized bouillon culture of swine-plague bacteria. It was inocu- 

 lated subcutaneously with virulent swine-plague bacteria Maj' 

 26, and died June 3, eight days later. The control rabbit died 

 within eighteen hours. The following changes were observed : 



A purulent infiltration into the subcutaneous tissue at the point of 

 inoculation extending over an area 6 cm. in diameter. The superficial 

 layer of the subjacent muscle discolored. Surrounding the area of infil- 

 tration the blood vessels were injected. The caecum and liver were cov- 

 ered with a very thin grayi.sh exudate, which also appeared on and be- 

 tween the coils of the intestine. Spleen not enlarged. ' 



The right lung and chest wall covered with a thin grayish exudate. 

 In the cephalic lobe, two small areas of consolidation ; principal lobe 

 hyperaemic. The left pleural cavity lined with a quite thick membran- 

 ous exudate, which covered the entire surface of the lung. On the dor- 

 sal surface of the principal lobe a mass of lung tissue 2 cm. in diameter, 

 firm and of a yellowish-gray color. The remaining portion of the prin- 

 cipal lobe hyperaemic ; cephalic lobe in a state of collapse. 



Pericardium covered with a thin cellular exudate. 



Higher degrees of resistance. — None of the treated animals 

 which have come under our observation, have succumbed to a 

 mere extension of the lesion produced at the point of inocula- 

 tion as is occasionally observed after inoculation with certain 

 varieties of swine-plague bacteria found in nature. There have 

 been noticed, however, certain peculiar localizations resem- 

 bling those produced in the subcutis after inoculation, and in 



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