PATHOGENIC BACTERIA AND DISEASES 55 



lymphatic gland (buboes); pulmonic, where the lungs 

 bear the brunt of the attack; septicemic, a generalized 

 form of the disease. 



Preventive Measures. Destruction of rats and their 

 fleas. The rat flea normally does not attack man, but 

 when the rats die and become cold the fleas leave the 

 bodies and seek warmth and nourishment wherever 

 they may be found. It is thus that they are forced to 

 seek sustenance upon an abnormal host. 



Vaccines have been used with some success in estab- 

 lishing immunity to the disease; an antitoxin is also 

 being used with encouraging results in the treatment. 



SPIRILLA 



Spirillum Choleras Asiaticae (Comma Bacillus of 

 Cholera). An aerobic, motile, non-spore-forming bac- 

 terium of the spirilla class. It is the cause of Asiatic 

 cholera, one of the most dreaded diseases of ancient 

 and modern times. 



The source of infection is usually drinking-water; less 

 frequently, food or other ingested material. 



The avenue of infection is always the intestinal canal. 

 Like typhoid fever, cholera is always a filth disease. To 

 be infected one must always swallow the excreta of some 

 1 one having the disease. Flies act as carriers, as in ty- 

 phoid. 



Lesions are localized in the intestinal canal and the 

 spirilla are not found in the blood. It is essentially a 



