374 APPLICATION OF METHODS OF BACTERIOLOGY 



one hour by 1 per cent, carbolic acid and in two hours by 

 1 per cent, milk of lime. 1 



It is pathogenic for rats, mice, guinea-pigs, ground squir- 

 rels, rabbits, hogs, horses, monkeys, cats, chickens, and 

 sparrows. Pigeons, hedgehogs, and frogs are immune, and 

 dogs and bovines are apparently so. 2 



Animals succumb to subcutaneous inoculation in from two 

 to three days. According to Yersin, the site of subcutaneous 

 inoculation becomes edematous and the neighboring lym- 

 phatics are enlarged in a few hours. After twenty-four hours 

 the animal is quiet, the hair is rumpled, tears stream from the 

 eyes, and later convulsions set in, which last till death. The 

 results found at autopsy are: blood-stained edema at the 

 site of inoculation, reddening and swelling of the lymphatic 

 glands, bloody extravasation into the abdominal walls, serous 

 effusion into the pleural and peritoneal cavities; the intes- 

 tine is occasionally hyperemic, the adrenal bodies congested, 

 and the spleen enlarged, often being studded with grayish 

 points, suggestive of miliary tubercles. The plague, or pest, 

 bacillus is detected in large numbers in the local edema, the 

 lymph-glands, the blood, and the internal organs. 



As is the case in general with the group of hemorrhagic 

 septicemia bacteria, the members of which it resembles in 

 certain other respects, when death does not result promptly 

 after infection there is usually only local evidence of the 

 inoculation, the distribution of the micro-organisms through- 

 out the body being considerably diminished. 



Animals that survive inoculation with this organism 



1 See Viability of the Bacillus Pestis, by M. J. Rosenau, U. S. Marine- 

 Hospital Service, Bulletin No. 4, of the Hygienic Laboratory, U. S. M.-H., 

 Washington, D. C., 1901. 



2 Nuttall, Centralblatt fur Bakteriologie und Parasitenkunde, 1897, 

 Abt. 1, Bd. xxii, S. 97. 



