io8 INFECTION AND IMMUNITY 



Dharwan 45 were subsequently attacked and 15 

 died ; while among 3387 persons in whom a second 

 inoculation was made, only 2 were attacked. Haff- 

 kine uses in his inoculations a sterilised culture of 

 the plague-bacillus. The inoculation is followed by 

 slight fever and enlargement of the nearest lymphatic 

 glands. All symptoms disappear at the end of two 

 or three days. 



The plague-bacillus is very easily destroyed by 

 disinfectants. Dr. Lowson reports that a i % solu- 

 tion of carbolic acid kills the bacilli within an hour, 

 a 2 % solution almost immediately. Quicklime was 

 almost as prompt in its action. Exposure to fresh air 

 for three or four days usually destroys the vitality of 

 the bacillus, and exposure to direct sunlight destroys 

 it in three or four hours. Kitasato and Yersin both 

 arrived at the conclusion that the disease may be 

 contracted by inoculation, through a wound or abra- 

 sion ; by way of the respiratory tract when the bacillus 

 is present in dust carried by the inspired air ; or by 

 way of the stomach when food or drink taken con- 

 tains the bacillus. 



What has been said indicates very clearly the 

 proper preventive measures, and when these are en- 

 forced with energy and intelligence there need be 

 little fear of the epidemic extension of the disease. 



For the prevention of this and other filth diseases, 



