CHAPTER XXXI 



ANTHRAX GROUP 



THE organisms Bacillus anthrads and Bacillus lactimorbi are 

 included in this group. It is possible that the latter organism 

 might better constitute the type of another group, but it resembles 

 the B. anthrads in a sufficient number of its morphological charac- 

 ters to render a tentative association of the two forms justifiable. 



The organisms belonging to this group are aerobic bacilli which 

 form spores, are gram-positive, and liquefy gelatin. These two 

 bacilli are the only pathogenic aerobic spore producers which have 

 been described. 



This group is in reality a subdivision of the much larger Badllus 

 subtilis, or hay-bacillus group of bacteria. Organisms closely 

 related morphologically and culturally to the Badllus anthrads 

 are ubiquitous ; they are found by tens of thousands in every gram 

 of most surface soils. A dozen or more species of these soil organ- 

 isms have been described, some of them so similar to the anthrax 

 bacillus that they can practically be differentiated only by suitable 

 animal inoculations. These bacteria are among the most active 

 in nature in bringing about the decomposition of organic substances 

 in the soil, particularly in the series of changes grouped together 

 under the heading of Ammonincation. 



Bacillus anthracis 



Synonym. Bacterium anthrads. 



Diseases Produced. Anthrax, splenic fever, Milzbrand, char- 

 bon in cattle, sheep, and rarely other animals; malignant car- 

 buncle, woolsorters' disease, in man. 



Pollender, in 1849, observed B. anthrads as minute rods in 

 the blood of cattle which had died of anthrax. Davaine also 

 observed and described it in the following year. The complete 

 proof that this organism causes the disease was furnished by the 



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