VACCINE TREATMENT OF TUBERCULOSIS 199 



amount of clinical material that has been satisfactorily studied is 

 entirely too small as yet, and it seems to me that we are really not 

 entitled to say more than that vaccination may do good and should 

 be tried. But we can neither state in what percentage of cases it 

 will be helpful or effect a cure, nor can we predict in an individual 

 case what the result will be. I have seen excellent results, and no 

 results, in apparently similar cases, and I feel that every unbiased 

 observer has similar experiences to record. It would after all be 

 expecting a great deal, in the absence of any more delicate indicator 

 to what is going on in the offensive-defensive interaction in the body, 

 than coarse clinical symptoms, to be obliged to predict what will 

 happen in a given case and whether we are doing the best that can 

 be done. 



While I have pointed out in the foregoing pages that we are not 

 yet in a position where we can speak definitely of the results of 

 vaccine treatment and its indications or contraindications, I must 

 modify this statement somewhat, so far as tuberculosis is concerned, 

 and it may not be out of place to consider this special question by 

 itself and in some detail. 



VACCINE TREATMENT OF TUBERCULOSIS 



The earliest attempts to influence the course of tuberculosis through 

 active immunization were made by R. Koch, and were based upon 

 the observation that a tubercular guinea-pig reacts quite differ- 

 ently to a subsequent inoculation with tubercle bacilli than does 

 a normal animal. For whereas in the latter a tubercular ulcer 

 develops at the site of the injection which does not heal, but per- 

 sists until the animal dies, local recovery occurs in the tubercular 

 guinea-pig without involvement of the regional lymph glands. 

 Evidently then the first inoculation, even though it leads to the 

 death of the animal, produces a certain degree of resistance, which 

 the untreated animal does not possess, and it very naturally occurred 

 to Koch that it might be possible to utilize this observation as a basis 

 for the treatment of human tuberculosis. Further indications for 

 experiments in this direction were afforded by the finding, that, 

 whereas the injection of large numbers of tubercle bacilli hastens 

 the death of the tubercular animal, small doses, frequently repeated, 

 seemingly have a beneficial influence both upon its general condition 



