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MANUAL OF BACTERIOLOGY. 



centuries, it devastated many of the countries of Europe, 

 where it was one of the most important of the pestilences 

 that went in those days by the name of the " Plague." It 

 appears to have been the disease known in English history 

 as the " Black Death." 1 



Bacillus aerogenes capsulatus. A thick bacillus, 3 to 6 

 fj- in length, frequently capsulated, discovered by Welch and 

 Nuttall. The capsules may be found in preparations from 



FIG. 67. 



Bacillus aerogenes capsulatus, Smear-preparation from Rabbit's Liver. 



(X 1000.) 



animal tissues, but rarely in cultures. It sometimes forms 

 spores chiefly in cultures on blood-serum. The vegetative 

 forms are destroyed at 58 C. moist heat in ten minutes, 

 but the spores withstand boiling nearly 8 minutes. It is not 

 motile. It stains by Gram's method. It is anaerobic, and is 



1 For further details concerning plague consult articles by Barker, 

 Novy and Flexner, Trans. Association American Physicians, 1902; 

 Calvert, American Medicine, January 24, 1903. 



