610 Tuberculosis. 



with characteristic sjaiiptoms of abdominal tuberculosis. 

 Geese and ducks may be infected in the same manner (Weber 

 & Bofinger). Pigeons possess a much greater power of re- 

 sistance to experimental infection. Articular tuberculosis is, 

 however, readily produced by injection of the bacilli into the 

 articulations. 



Rabbits are very susceptible to experimental inoculation, 

 and the feeding of cultures to these animals produces symptoms 

 very similar to those following infection with bovine tuber- 

 culosis (intravenous administration of the virus is frequently 

 followed by tuberculosis of the joints and of the adjacent bones 

 and tendon sheaths). On the other hand, guinea pigs offer 

 a somewhat greater resistance to such infections; although 

 they get sick after treatment Avitli rather large amounts of 

 virus, morbid changes (nodules and ulcers) usually develop 

 only around the masses of bacilli found in the body and which 

 always develop rather slowly (much the same as lesions oc- 

 curring around other foreign bodies). A progressive tuber- 

 culosis is a rare occurrence. Intraperitoneal infection, how- 

 ever, produces death from tuberculous septicemia ("Type 

 Yersin") (0. Bang). The virulence of the bacilli is frequently 

 completely destroyed in the bodies of guinea pigs (M. Koch & 

 Rabinowitsch). Of the larger mammals, cattle and goats 

 respond to subcutaneous injection much like guinea pigs. In- 

 traperitoneal administration causing death from tuberculous 

 septicemia. Animals of mature age are very resistant to the 

 alimentary administration of avian tubercle bacilli while very 

 young animals (calves, kids and colts) develop acute tuber- 

 culosis which affects the intestines and mesentery with par- 

 ticular severity, occasionally also the lungs, and which ter- 

 minates fatally (0. Bang). Swine seem to be only slightly 

 susceptible, dogs and cats not at all, while mice and rats are 

 readily infected through the alimentary tract. 



Natural infection of healthy fowls is brought about by 

 taking up the droppings of infected birds. When intestinal 

 ulcers are present such droppings contain enormous masses 

 of bacilli. Still more frequently is infection brought about by 

 permitting healthy fowls to have access to tuberculous cadavers 

 that have been consigned to the manure pile. The liver and 

 spleen of such cadavers contain large masses of bacilli. 



Infection from tuberculous persons. In view of the very 

 slight susceptibility of fowls to infection with mammalian 

 tuberculosis (which has been demonstrated experimentally) 

 infection from the sputum of human beings probably occurs 

 only in such rare cases in which the lung secretions of con- 

 sumptives contain avian tubercle bacilli (see p. 618). Infec- 

 tion from tuberculous mammals is undoubtedly also a rare 

 occurrence (parrots, however, are an exception in this respect. 

 See p. 615). On the other hand, the possibility exists that 



