4 6 ° PATHOGENIC BACTERIA. 



ular edges, from which sufficient bacillary threads pro- 

 ject to give it a ciliated appearance to the naked eye. 

 When the culture is old the agar-agar turns a distinct 

 brown. Spore-formation is luxuriant upon agar-agar. 



On potato the growth is white, creamy, sometimes 

 rather dry in appearance. Sporulation is marked. 



Blood-serum cultures lack peculiarities ; the culture- 

 medium is slowly liquefied. 



The bacillus only grows between the extremes of 20 

 and 45° C, best at 2,7° C. The exposure of the organ- 

 ism to the temperature of 42-43 C. for twenty-four hours 

 is sufficient to destroy its virulence. 



The culture-media should always be faintly alkaline, as 

 anthrax bacilli will not grow in the presence of free acid. 



The micro-organism under consideration is a parasitic 

 microbe, yet is one which, because of its spores, can, in 

 a latent form, exist without the animal organism until 

 appropriate conditions for its natural development are 

 presented. 



Ordinarily, the infection takes place either through the 

 respiratory tract or through the alimentary canal. 



Buchner has shown that when animals are allowed 

 to inhale anthrax spores they die of typical anthrax. 

 The spores establish themselves in the alveoli of the 

 lung, penetrate the epithelium, enter the vascular sys- 

 tem, and soon give rise to typical lesions. Strange to 

 say, the appearance caused by the inhalation of the 

 bacilli in their perfect form is entirely different, for a 

 rapid multiplication occurs without sporulation, and 

 causes a violent irritative pneumonia with serous or sero- 

 fibrinous exudate in which large numbers of the bacilli 

 occur. In these cases there may be no general infection. 



When the bacilli are taken into the stomach in food 

 they meet with a rapid death because of the acidity of 

 the gastric juice. Should spores, however, be ingested, 

 they are able to endure the gastric juice, to pass into the 

 intestine, and, as soon as proper conditions of alkalinity 

 are encountered, to develop into bacilli. They develop 



