EXPERIMENTS WITH PURE CULTURES 149 



nodule was found in one of the bronchial glands ; but 

 there was no other evidence of tubercular disease in 

 the body. The remaining organs and tissues, with the 

 exception of the intestines, showed no pathological 

 lesions, though there was very little fat present in any 

 of the usual situations. The intestine, on examination, 

 showed a moderate degree of thickening, especially in 

 the ileum and caecum near the ileo-caecal valve. Films 

 were made in the usual manner from beneath the 

 mucous membrane, and after a prolonged examination 

 several typical Johne's bacilli were found in those from 

 the region of the ileo-caecal valve. Cultures were 

 made from a number of the glands and from the sub- 

 mucous tissue of the gut on to tubes of Dorset's egg- 

 medium. The tubes were capped with gutta-percha 

 tissue and incubated at 39° C. After five days the 

 small pieces of tissue were removed from the Dorset's 

 egg medium and placed on to tubes of tubercle bacillus- 

 egg medium and timothy-grass bacillus egg-medium. 

 One tube of the latter medium, on which was placed 

 material from the ileo-caecal valve, showed definite 

 microscopic evidence of growth in twenty-five days. 

 This culture, the only one obtained, was easily sub- 

 cultured on to fresh tubes of the special medium, but 

 failed to grow on ordinary Dorset's egg medium. The 

 acid-fast bacillus in the bronchial glands was isolated 

 on Dorset's egg medium, and it possessed all the 

 characteristics of a typical bovine tubercle bacillus. 

 It is interesting to note that although this animal had 

 contracted typical Johne's disease, yet, in spite of the 

 tuberculosis, which might be expected to lower the 

 resistance of the animal, the disease was in a very early 

 stage. This experiment is further evidence of the 

 slow progress of the disease. 

 The strain of Johne's bacillus isolated from this calf, 



