74 JOHNKS DISEASE 



enteritis, and a considerable number of acid-fast bacilli 

 were present in the lesions. Cultures were made 

 from several parts of the specimen directly on to 

 twelve tubes of Dorset's egg medium. They were 

 taken in the manner already described, but as the 

 specimen was fresh on arrival, previous treatment with 

 ericolin solution was unnecessary. The tubes were 

 capped with gutta-percha tissue, and placed in the in- 

 cubator at 39° to 40° C. On the following day they 

 were examined, and found to be free from contami- 

 nating colonies, so the tiny pieces of tissue were 

 removed from three of these tubes and placed on to 

 three tubes of the special tubercle bacillus medium. 

 These were capped, and placed in the incubator with 

 the other tubes at 39° to 40° C. Six weeks later the 

 three tubes of special medium showed a few tiny 

 colonies of Johne's bacillus. Compared with the pre- 

 vious cases the rapidity of growth was very slow, and 

 was slight in amount, due, as was proved later, to the 

 unsuitability of the particular strain of tubercle bacillus 

 incorporated in the medium. Subcultures from these 

 tubes on to tubes of a fresh batch of tubercle medium 

 grew well. All the original cultures on Dorset's egg 

 medium remained sterile, as also did subcultures from 

 the special medium on to Dorset's egg medium. 



The experiments with these cases (2 to 5) prove 

 definitely that it is possible to isolate from the intes- 

 tines of cattle suffering from Johne's disease an acid- 

 fast bacillus which will grow on a medium contain- 

 ing the dead bodies of human tubercle bacilli, but 

 will not grow on any of the ordinary laboratory 

 media. 



Slight modifications in the constitution of the medium 

 were now made, and it was found that media containing 

 about 4 per cent, of glycerine yielded the best results. 



