212 



DISEASES OF POULTRY. 



the body are affected— the tubercles being found even 

 in the interior of the bones. 



The joints are frequently the seat of tubercular in- 

 flammation leading to swelling, abscesses, ulcers,, 

 fistulas and loss of 

 movement. Swellings, 

 ulcers, and cheesy 

 formations are some- 

 times seen about the 

 mouth, eyes and nose, 

 and horny excrescences 

 may appear upon the 

 skin of the head. 

 These external mani- 

 festations are the rule 

 with parrots. 



Cause and Na- 

 ture. — The tubercu- 

 losis of birds, like that 

 of mankind, is caused 

 by a bacillus. The 

 bacillus of birds in a 

 general way resembles 

 that of man, but is 

 larger, more vigorous 



and hardy, and grows Fig-. 63.— Section of liver of bird affected 



better outside of the with tuberculosis. 



body. The disease is strictly contagious, and 

 usually appears in a flock as a consequence of bring- 

 ing in new birds. That is, it results from contagion 

 carried by birds from other diseased flocks. 



Many outbreaks have been attributed to infection 

 from eating the sputum of persons affected with con- 

 sumption. The possibility of such infection is ad- 



