DISEASES AND PESTS OF FOWLS 



aroused if birds gradually lose weight and 

 die. If a bird that 

 has gradually been 

 getting thinner, goes 

 lame, or loses the use 

 of a wing, without ap- 

 parent injury, the evi- 

 dence that tuber- 

 culosis is present is 

 strong, but positive 

 proof of its presence 

 can be obtained only 

 by post-mortem and 

 microscopic examina- 

 tion. This disease gen- 

 erally attacks adult 

 birds. 



Cause. The specific 

 organism causing this 

 disease, known as the 

 Bacillus tuberculosis 



(FlO" ^ inferfrS the FlG - 24 - ORGANS AFFECTED BY 

 \* *& ^/J J U-CUI& LllC TUBERCULOSIS AND BLACKHEAD 



liver (Fig. 24), the a . Normal spleen . 



i /T7' \ J ^- Tubercular spleen. 



Spleen (-Tig. 24J, and c. Portion of tubercular liver. 

 t d. Blackhead liver of turkey for 



other organs, least f re- comparison with c. 



a and b after Edwards. 



