EXPERIMENTS WITH INFECTED MATERIAL 141 



sometimes occur with the avian tubercle bacillus, these 

 authors concluded that they were dealing here with 

 this micro-organism. It is now known that this was 

 not so, and in the light of further experiments it is 

 possible that the transitory illness of these animals 

 was due to contaminating intestinal micro-organisms 

 in the inoculated mucous membrane, and not to any 

 toxic effect of Johne's bacillus. 



In 1904, Markus inoculated subcutaneously six 

 guinea-pigs and two rabbits, and fed two rabbits and 

 three hens with infective material. The animals, all 

 of which had increased in weight, were killed within 

 periods of from 1 50 to 300 days, and were found post 

 mortem to be quite normal. Stuurman, by feeding 

 a rabbit with material from the intestine of an affected 

 cow, produced abscesses in the intestines, and from 

 these cultivated in pure growth an acid-fast bacillus 

 which was afterwards proved to be the avian type of 

 tubercle bacillus. B. Bang experimented with the 

 diseased intestines and glands that he obtained from 

 fourteen cows by inoculating a number of small 

 animals. The material obtained from two of these 

 cows, which came from tuberculous herds, produced 

 typical tuberculosis in guinea-pigs, rabbits, and calves. 

 Bang, however, produced Johne's disease in three 

 calves by feeding them with large quantities (from i to 

 3 pounds) of the mucous membrane of a cow which was 

 killed while suffering from the disease. 



Miessner and Trapp, at the Agricultural Institute at 

 Bromberg, made a number of animal inoculations with 

 material from eight cases of naturally acquired Johne's 

 disease. One of the experimental calves on post- 

 mortem examination showed well-marked lesions of 

 Johne's disease, but no signs of tuberculosis. The 

 following experiments were made with material from 



