214 DISEASES OF POULTRY. 



and from avian to mammalian, but such a change cer- 

 tainly would require much time and very favorable 

 conditions. 



A very interesting fact is that parrots are usually 

 affected with the mammalian form of tuberculosis. 

 The disease is quite frequently seen in these birds and 

 it shows a great tendency to develop externally. It 

 most commonly affects the borders of the eyes and 

 mouth, the skin and the joints of the feet. There are 

 at first small swellings, some of which soften, dis- 

 charge their contents and become ulcers; others re- 

 main hard and continue to enlarge, while still others 

 are covered by a horny growth of considerable thick- 

 ness. When the feet are affected the joints swell and 

 the bones are more or less deformed, leading many 

 who are not well informed on the subject to consider 

 the disease as simple gout. 



It has been shown by experiments that it is very 

 difficult to infect fowls and pigeons by inoculation 

 from parrots, but rabbits, guinea pigs and dogs read- 

 ily contract the disease by such inoculation. It is 

 concluded from the various facts which have been re- 

 corded, that the tuberculosis of parrots is identical 

 with tuberculosis or consumption in man ; that parrots 

 are infected from diseased people and may in turn in- 

 fect other people. The germs of the disease are 

 found in enormous numbers in the discharge from the 

 ulcers, in the secretion of the nasal passages and often 

 in the excrement. The cages are soiled with these 

 different excretions, which soon become dry, are re- 

 duced to dust and then disseminated through the air 

 of the apartment by the flapping of the bird's wings. 

 People breathing this atmosphere take the germs into 

 their lungs and in that way become infected. Other 



