96 ANNUAL REPORT. OF THE. Off. Doc, 



In all of the treated auimals tlie lesions were quiescent and encap- 

 siilalcd. But they conlained livin"; tubercle bacilli. There is room 

 for dili'erence of opinion as to whether an animal or a person in which 

 there is a tuberculous lesion containing living bacilli may be regarded 

 as cured. If the lesion is wholly cut oil by a thick fibrous wall from 

 living tissue and if it is incapable of again becoming active, it would 

 appear that a claim for a cure might fairly be entered. But how is 

 one to know that activity may not be reestablished? If there is 

 resistance enough to cause the complete encapsulation of all tuber- 

 culous lesions iu the body, it is evidence that a considerable degree 

 of inuuuuity had been developed. If the bacilli in the lesions are of 

 such low virulence that they cannot infect an animal of the species 

 of the one iu which they are found, renewed activity is not to be 

 expected. Dr. Hchweintz found living tubercle bacilli in minute 

 nodules in the lungs of a cow inoculated intravenously a year before 

 with bacilli of human type that appear to have been incapable of pro- 

 ducing progressive disease. Nodules may occur from intravenous 

 injections of dead tubercle bacilli. Fraenkel and Von Behring have 

 found in lesions of tuberculosis of cattle tubercle bacilli that are not 

 pathogenic for cattle. 



Unfortunately, in these experiments, the virulence for cattle of the 

 tubercle bacilli in the lesions in the treated animals was not deter- 

 mined. 



These experiments which were made on a few young cattle in the 

 earlier stages of tuberculosis do not justify conclusions or inferences 

 r.y to the probable effect of similar treatrnent on older and more exten- 

 sively diseased animals. Experiments must be made on a larger and 

 broader scale. We have at this time a number of animals under 

 treatment which we hope will give us more knowledge on this sub- 

 ject. 



But we hold that the experiments that have been made show 

 clearly that under such treatment as was given tuberculous lesions 

 do not extend; on the contrary, that they recede and that new im- 

 I)lautations do not occur even upon prolonged contact with tubercu- 

 lous herd mates. 



