ANTHRAX 163 



(b) When cultures are allowed to reimain some months 

 before subcultures are made. 



(c) After the organism, has been subcultured a consider- 

 able number of times. 



(d) When exposed to sunlight. 



Cultures which are so attenuated that their injection into 

 guinea-pigs is not fatal may have their virulence restored 

 by passing two or three times through young mice. 



Immunity, which, however, according to Petermann, is 

 transitory, seldom lasting more than a few months, may be 

 conferred upon susceptible animals by successive injections 

 into their blood of either — 



(a) Attenuated cultures ; 



(b) Filtered cultures {bacilli-free) ; or 



(c) The blood serum of immunised anvmals. 



When protected animals are inoculated with a virulent 

 culture, the bacilli do not enter the circulation, and only 

 local suppuration occurs. 



Up to the end of 1890 over three million head of cattle 

 have been inoculated with attenuated anthrax virus prepared 

 at the Pasteur Institute, Paris. 



Practical Disinfection, — Any animal dead of anthrax must 

 be buried deep in the ground, and then the putrefactive 

 organisms will kill the anthrax bacilli, and no spores will 

 be found. Discharges from an infected animal are highly 

 dangerous to man and other animals, so that stables 

 polluted with infective discharges should be washed out 

 with a strong solution of bleaching-powder (8 ounces to 

 the gallon), and harness, if possible, disinfected. It is 

 best and safest to destroy the carcase by burning in a 

 ' destructor.' Lately a process of destroying carcases has 

 been introduced in which the entire animal is dissolved in 

 sulphuric acid. 



11—2 



