214 PHARMACEUTICAL BACTERIOLOGY. 



entire body of the patient should be washed with a disinfecting solution 

 (1-1200 bichloride of mercury). Disinfect everything used about the 

 patient. After death or recovery everything used by the patient should be 

 destroyed by burning. 



Rats (bearing the infected fleas) are the principal carriers of this disease, 

 and the experience in San Francisco (1906-1909) has demonstrated that 

 plague disappears as soon as the plague infested rats disappear. Destroy 

 rats and mice and see to it that the home is free from fleas. Plague is a 

 quarantinable disease and the federal authorities are constantly on the look- 

 out to prevent the importation of this disease. The Oriental ports are the 

 chief sources of infection. 













Fig. 83. Fig. 84. 



Fig. 83. — Bacillus pestis. Does not form spores and is very easily killed. The ends 

 stain more heavily than the middle. Involution forms may accur. Sometimes the cells 

 become encapsuled as shown in the figure. 



Fig. 84. — Bacillus cholera also known as Spirillum choleras, the cause of Asiatic 



cholera. 



Yersin's anti-plague serum and Haffkine's bacterin have been used with 

 considerable success as prophylactics and also with some success as cures. 



I. Asiatic Cholera. — This is another filth disease essentially of Oriental 

 origin, particularly prevalent in the crowded unsanitary cities of India and 

 Asia. It is a quarantinable disease. The primary cause is the non-spor- 

 ogenous Bacillus cholerce {Spirillum cholera) also known as the comma 

 bacillus of Koch. The principal sources of the infection are polluted water 

 and food, particularly the former. In fact the sources of infection and modes 

 of entry into the digestive tract are not unlike those of typhoid. Cholera is 

 highly infectious and usually occurs epidemically, often spreading over wide 

 areas. Human excrement carries the infection and when this material is 

 used as fertilizer, which is done in China and other Oriental countries, it 

 becomes the means of initiating and continuing the spread of the disease. 

 The importing by the Chinese of human excrement and animal dung for 



