178 ANNUAL REPORT OF THE Off. Doc. 



to tuberculin has any relation to the degree of immunity that the 

 animal may have against tuberculosis. 



We come now to consider the animals which had reacted to the 

 tuberculin test ^nd were considered to be of sulticient value to be 

 placed upon the liaug system with the main object of saving their 

 oti'spring. From the reacting animals in 11)0-4, twenty-four cows, 

 heifers and bulls were saved. In 1905 there were eleven animals re- 

 served for this purpose. 



These animals were thoroughly isolated from the main milking 

 herd, attended by one man and the milk was adequately pasteurized 

 before being used for any purpose. 



In 1004 Dr. Leonard Pearson and the writer published an article 

 entitled, "The Effect of Tuberculosis Vaccination upon Cattle In- 

 fected with Tuberculosis." The experiment was made upon twelve 

 yearlings of the Shorthorn breed. The animals were approximately 

 the same age and size and had, just prior to the starting of the ex- 

 periment, reacted to the tuberculin test. It was believed that the 

 lesions they contained were not far advanced and they would be good 

 subjects for such work. In conclusion, the article states: "we believe 

 we have sufficient evidence to justify the statement that the treatment 

 to which six of the animals were subjected had the effect of not only 

 keeping in check the progress of a tuberculous process but in causing 

 a distinct and in some cases a great retrogression of the lesions. In 

 other words the treatment had a distinct curative effect." With this 

 knowledge at hand, it was decided to keep the valuable reacting ani- 

 mals of this herd, isolate and handle them in accordance with the 

 Bang system, as well as to treat them with tuberculosis vaccine and 

 tuberculin. 



They were first given an intravenous injection of tuberculosis 

 vaccine. The dose depended upon the age, size and physical condition 

 of the animal and ranged from 4cc. to 10 cc. of a standard suspension 

 of tubercle bacilli of the human type. This was followed at inter- 

 vals of seven days with increasing doses of tuberculin until three in- 

 jections were given. Then a second injection of tuberculosis vac- 

 cine, the dosage being the same as the initial injection, was given. 

 This was followed by three weekly injections of tuberculin, increasing 

 the dose wnth each injection. Finally, a third dose of tuberculosis 

 vaccine was given followed by weekly injections of tuberculin, in- 

 creasing the dosage at each injection until the animal ceased to 

 react. 



I regret very much that I do not have a complete record of the 

 offspring of these animals, but I feel safe from the information I 

 have at hand to state that fifty per cent, of all calves were saved. 

 The plan was to remove the calf from the infected stable as soon as 

 dropped, sponge it thoroughly with a solution of creolin, remove 

 it to non-infected quarters and to feed it artifically upon ])asteurized 

 or sterilized milk. In some of the animals the treatment seemed to 

 have no beneficial results, while in others most encouraging results 

 were obtained. These animals were slaughtered at various times 

 throughout the experiment, the last being killed April 19, 1907. In 

 eight animals of the thirty-five animals in the experiment no micro- 

 scopical lesions of tuberculosis could be determined after a careful 

 postmortem examination. In ten of the remaining animals, only 



