CAUSING ACUTE INFECTIONS. 79 



which progresses to ulceration and gangrene. If this 

 is opened promptly recovery may follow. Among 

 those working on raw wool, hides, and horsehair the 

 disease may be acquired by inhaling the spores. Infec- 

 tion contracted in this manner causes a pneumonia, 

 often called wool-sorters' disease. 



Fig. 9. Anthrax bacilli. Spore formation and spore germi- 

 nation. A, from the spleen of a mouse after twenty-four hours' 

 cultivation in aqueous humor. Spores arranged in rods like a 

 string of pearls. X 650. B, germination of spores. X 650. C, 

 the same, greatly magnified. X 1650. (Koch.) 



The disease is prevented from spreading by 

 destroying the infected animals, burying their bodies 

 and disinfecting the stables. 



No toxins are formed by the anthrax bacillus. It immunity 

 is possible to immunize animals by injecting the 

 bacilli that have been attenuated by long growth at a 

 temperature of 42 C. The blood-serum of animals 

 immunized in this way contains the protective sub- 



