42 ESSAYS ON BACTERIOLOGY. 



reacliings out into such experiments as the Koch 

 treatment of tuberculosis, the preventive inoculation 

 against rabies, tetanus and diphtheria? We are ap- 

 proaching the pressing question of immunity, and, 

 for practical medicine, the greatest problem of our 

 day: Can we, and how best shall we, combine science 

 and art to confer upon humanity the inestimable boon 

 of immunity or cure, or both cure of and immunity 

 from the infectious diseases? 



