314 BA OTEBIOL OGY. 



temperature in four days. It is killed in three or four 

 hours by direct sunlight. It is destroyed in a half hour 

 by 80° C, and in a few minutes by 100° C. (steam). 

 It is killed in one hour by 1 per cent, carbolic acid 

 and in two hours by 1 per cent, milk of lime.^ 



It is pathogenic for rats, mice, guinea-pigs, rabbits, 

 hogs, horses, monkeys, cats, chickens, and sparrows. 

 Pigeons, hedgehogs, and frogs are immune, and dogs 

 and bovines are apparently so.^ Animals succumb to 

 subcutaneous inoculation in from two to three days. 

 According to Yersin, the site of subcutaneous inocu- 

 lation becomes oedematous 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 oedema at the site of inoculation, reddening and 

 swelling of the lymphatic glands, bloody extravasation 

 into the abdominal walls, serous eifusion into the pleu- 

 ral and peritoneal cavities ; the intestine is occasionally 

 hypersemic, the adrenal bodies congested, and the spleen 

 enlarged, often being studded with grayish points, sug- 

 gestive of miliary tubercles. The plague, or pest, ba- 

 cillus is detected in large numbers in the local oedema, 

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



As is the case in general with the group of hemor- 

 rhagic septicaemia bacteria, the members of which it 

 re.sembles in certain other respects, when death does not 

 result promptly after infection there is usually only 



' See " Viability of the Bacillus Pestis," by M. J. Eosenau, U. S. 

 Marine-Hospital Service, Eulletiu No. 4, of the Hygienic Laboratory, 

 U. S. M.-H., Washington, D. C, 1901. 



"Nuttall: Ceutralblat fiir Baktcriologie und Farasiteulcunde, 1897, 

 Abt. i, Bd. xxii, S. 97. 



