CHOLERA 181 



living bacilli and their products are injected together. 

 There is no danger of imparting cholera by this pro- 

 cedure, as the cholera bacilli cannot live in the blood. 

 Both vaccines may, if desired, be carbolised, in which case 

 they will be sterile ; but their power is unimpaired, and 

 they may be preserved indefinitely in sealed tubes. 



