PATHOGENIC BACTERIA. 97 



Feeding. The cattle graze upon the meadows, where the 

 blood of anthrax animals has flowed and become dried, the 

 spores remaining, which then mix with the grass and so enter 

 the alimentary tract ; here they then cause the intestinal form 

 of the disease, ulcerating through the villi. 



Local Infection. In man usually only a local action occurs ; by 

 reason of his occupation wool-sorter, cattle-driver, etc., he 

 obtains a small wound on the hand, and local gangrene and 

 necrosis set in. 



Pneumonia by inhalation and intestinal infection also occurs 

 in man. 



Susceptibility of Animals. Dogs, birds, and cold-blooded ani- 

 mals affected the least ; while mice, sheep, and guinea-pigs 

 quickly and surely. 



Products of Anthrax .Bacilli. A basic ptomaine has not been 

 found, but a toxalbumen or proteid, called anthraxin, has been 

 obtained. A certain amount of acid is produced by the virulent 

 form, alkali by the weak. 



Attenuation and Immunity. Cultures left several days at a 

 temperature between 40 and 42 C. soon become innocuous, and 

 when injected into animals protect them against the virulent 

 form. 



The lymph obtained from lymph-sac of a frog destroys the 

 virulence of anthrax bacilli and spores temporarily. 



Hankin obtained an alexin from the blood and spleen of rats, 

 they being naturally immune. It destroyed the anthrax bacilli 

 in vitro, and used by injection in susceptible animals made 

 them immune. It is insoluble in alcohol or water. 



Protective Vaccination. Animals have been rendered immune 

 by various ways by inoculation of successive attenuated cul- 

 tures ; also witli sterilized cultures that is, cultures containing 

 no bacilli, and with cultures of other bacteria. 



Habitat. The anthrax disease seems confined to certain dis- 

 tricts in Siberia, Bavaria, and Auvergne, and mainly during the 

 summer months. 



The bacillus has never been found free in nature. 



Bacillus Tuberculosis. (Koch.) 



This very important bacillus was first described, demonstrated, 



