]4(J POULTRY DISEASES 



eent ereulio, all fences, feed troughs, watering tanks and 

 l)uildings, as indicated under cholera. 



Tlie tubercle bacillus is resistant to external influence. A 

 contaminated poultry yard may remain infected for a long 

 time, many months and possibly years. The action of disin- 

 fectants on the tubercle bacillus is slow. Direct sunliglit on 

 the surface of infected material kills the bacillus in a few 

 hours. 



Birds from an infected flock should not be sold for ])reed- 

 ing purposes, and the birds from such a flock that are killed 

 for foocl should be inspected by a competent veterinarian, so 

 that none may be used for food purposes that are diseased 

 to such an extent as to render the food unfit for use. 



All birds in a flock infected with tuberculosis that die 

 should be cremated to prevent further spread of the disease 

 from that source. All drop])ings and cleanings from the hen- 

 house and runs should be disinfected with calcium chlorid, a 

 five per cent solution of carbolic acid or other reliable disin- 

 fectant before spreading on the fields. 



Inoculations of Birds by Mammalian Strams 



Aiiclair has found that pigeons injected intraperitoneally with 

 pure cultures of human tubercle bacilli, died after one to three 

 and one-half months, without showing any signs of tuberculosis. 

 In a second series, pigeons were infected in a similar manner with 

 tubercle bacilli from a similar source. At the sixth, seventh and 

 fourteenth days afterward, the pigeons were killed and the livers, 

 lungs and blood injected into guinea pigs. A few of the pigs died 

 without any evidence of tuberculosis. Only two died of local tuber- 

 culosis. 



From this Auclair concludes: first, th:it pigeons infected with 

 human tubercle bacilli die without any observable tuberculous 

 changes; second, that tubercle bar-illi may retain their vitality and 

 virulence in the body of the pigeon, for at least fourteen days: 

 third, that the tubercle bacilli localize themselves in the pigeon 

 by preference in the liver and in the lungs, but not. so far as 

 could be shown, in the blood; and fourth, that the tubercle bacilli 

 passed through the pigeon give rise to a slowly developing tuber- 

 culosis. 



Van Es and Schalk after experimenting with many chickens 

 corne to the following conclusions: 



A considerable number of birds into which mammalian tubercle 

 bacilli are introduced, either by ingestion or by inoculation, die in 

 an extremely emaciated state. 



As a result of the incorporation of such bacilli into the bodies 

 of birds, the latter may retain the organisms for long periods with 

 their pathogenic characteristics fully preserved. 



In consequence it is well within the range of possibility that 

 biros may serve as intermediary carriers and transmitters of mam- 

 malian tuberculosis. 



