Metabolism 589 



Vital Resistance. Kitasato found that the plague 

 bacillus did not seem able to withstand desiccation longer 

 than four days; but Rappaport* found that they remained 

 alive when kept dry upon woolen threads at 20 C. for 

 twenty-three days, and Yersin found that although it could 

 be secured from the soil beneath an infected house at a depth 

 of 4 to 5 cm., the virulence of such bacilli was lost. 



Kitasato found that the bacillus was killed by two hours' 

 exposure to 0.5 per cent, carbolic acid, and also by exposure 

 to a temperature of 80 C. for five minutes. Ogata found 

 the bacillus instantly killed by 5 per cent, carbolic acid, and 

 in fifteen minutes by 0.5 per cent, carbolic acid. In o.i per 

 cent, sublimate solution it is killed in five minutes. 



According to Wyman, the bacillus is killed by exposure 

 to 55 C. for ten minutes. The German Plague Commission 

 found that the bacilli were killed by exposure to direct sun- 

 light for three or four hours; and Bowhillf found that they 

 are killed by drying at ordinary room temperatures in about 

 four days. 



Wilson I found the thermal death-point of the organism 

 one or two degrees higher than that of the majority of 

 non-sporulating pathogenic bacteria, and that the influ- 

 ence of sunlight and desiccation cannot be relied upon to 

 destroy it. 



Rosenaui found temperature the most important factor, 

 as it dies quickly when kept dry at 37 C., but remains alive 

 for months when kept dry at 19 C. Sunlight kills it in a 

 few hours. A temperature of 70 C. is invariably fatal in 

 a short time. 



Metabolism. The bacillus develops under conditions of 

 aerobiosis and anaerobiosis. In glucose-containing media 

 it does not form gas. No indol is formed. Ordinarily the 

 culture-medium is acidified, the acid reaction persisting for 

 three weeks or more. 



Ghon,|| Wernicke,** and others who have studied the toxic 



* Quoted by Wyman. 



f "Manual of Bacteriological Technique and Special Bacteriology," 

 1899, p. 197. 



t "Journal of Medical Research," vol. vi, No. i, p. 53, July, 1901. 

 Bulletin No. 4 of the Hygienic Laboratory of the U. S. Marine 

 Hospital Service, 1901. 



|| Wien, 1898. 

 ** "Centralbl. f. Bakt.," etc., 1898, xxiv. 



