ANIMALS SUSCEPTIBLE TO TUBERCULOSIS. 309 



tubercular processes are man, apes, cattle, horses, sheep, 

 guinea-pigs, pigeons, rabbits, cats, and field mice. 



^yhite mice, dogs, and rats possess immunity against 

 the disease. 



We have reviewed the three common pathogenic 

 organisms with which we may come in contact in the 

 sputum of tuberculous individuals. Occasionally other 

 forms may be present. The pyogenic forms are not 

 rarely found, and for some time after diphtheria the 

 bacillus of Loeffler is demonstrable in the pharj-nx, so 

 that it, too, may be present under exceptional circum- 

 stances. These latter organisms will be described under 

 their proper heads. 



From time to time fowls are known to suffer from 

 a form of tuberculosis that is in many respects similar 

 to human tuberculosis both as regards pathological 

 lesions and etiology. The bacillus causing the dis- 

 ease, while very much like the genuine bacillus tuber- 

 culosis morphologically, differs from it in cultural pecu- 

 liarities, notably in its inability to produce general 

 tuberculosis in rabbits and guinea-pigs; in its growth 

 into long branched forms at 45° to 50° C; and in its 

 nev^er having been detected in human or mammalian 

 tuberculosis. 



Anatomical lesions very suggestive of those produced 

 by bacillus tubei'culosis have also from time to time been 

 observed in certain rodents. They do not appear to be 

 of specific nature as regards etiology, for the reason that 

 different authors have described different species of 

 bacilli as the causative agents. The disease suggests 

 tuberculosis only by the more superficial character of 

 its lesions, for in no instance have the organisms de- 

 tected been in any way similar to the genuine bacillus 



14* 



