ESSAYS ON BACTERIOLOGY. 69 



authors having thought to modify and improve Koch's 

 tuberculin by excluding some of the harmful constit- 

 uents. Klebs has claimed to accomplish the same re- 

 sult, and considerable interest has been taken in his 

 modified tuberculin, the so-called tuberculo-cidin. In 

 spite of these claims, it is evident that the results 

 gained by following this particular line of experi- 

 ments has not been great. It evidently yet remains 

 to find an agent which approaches a specific for tuber- 

 culosis. Nevertheless, bearing in mind the remark- 

 able developments of the last few years, the great 

 progress made in clearing up the mystery of proteids, 

 and remembering the astonishing antagonism which 

 may exist between different bacteria, even between 

 harmless and "\arulent ones, there is certainly room for 

 hope. I believe that the day will come, it may come 

 soon, it may be long delayed, but the day will come 

 when tuberculosis will be as thoroughly at our mercy 

 as is smallpox to-day. It will have sunk to the insig- 

 nificance of a beaten and imprisoned enemy. I hope 

 and expect to see it before my hair has grown gray. 



