78 JOHNE^S DISEASE 



Johne's bacillus, when inoculated on to media con- 

 taining Nos. I, 2, 5, 6, and 7, gave a good growth ; but 

 on the rest growth was usually absent, though a very 

 slight film was occasionally present on the media con- 

 taining some of the Tobler varieties. 



A number of blastomyces, streptothrices, cocci, and 

 bacilli that are not acid-fast, were also tested, but no 

 growth was obtained on media containing any of these 

 micro-organisms. In all such experiments we used 

 strains of Johne's bacillus that had been isolated on 

 the tubercle bacillus-egg medium, and that had been 

 growing outside the animal body for a considerable 

 time, and it was thought that the good growth ob- 

 tained with B, phlei medium might be due to the fact 

 that our strains were becoming acclimatized to arti- 

 ficial culture media. To test this point we made 

 primary cultures on to a B. phlei medium. A further 

 specimen of diseased gut was obtained through the 

 kindness of Mr. De Vine. In this case the disease was 

 in a very early stage, and the thickening of the intes- 

 tines was only quite moderate. Films were made from 

 the ileum and ileo-caecal valve, but only a very few 

 acid-fast bacilli could be found after a prolonged search. 

 Cultures, however, were made from the regions show- 

 ing most bacilli, on to tubes of Dorset's egg medium, 

 and also on to tubes of B, phlei medium. After five 

 weeks' incubation there was no evidence of growth 

 on Dorset's egg medium, but on the B. phlei medium 

 definite evidence of multiplication was observed. 

 Subcultures from the B. phlei medium on to fresh 

 tubes of the same medium grew well, as also did those 

 on a medium containing the human tubercle bacillus, 

 but on ordinary laboratory media there was no growth. 



The bacillus isolated resembled in every way the 

 bacilli isolated from the four previous cases, and the 



