CHAPTER VII. 

 CHICKEN- CHOLERA. 



THE barnyards of Europe, and sometimes of America, 

 are occasionally visited by an epidemic disease which 

 affects pigeons, turkeys, chickens, ducks, and geese, and 

 causes almost as much destruction among them as the 

 occasional epidemics of cholera and small-pox produce 

 among men. Rabbit-warrens are also at times seriously 

 affected by the epidemic. When fowls are ill with the 

 disease, they fall into a condition of weakness and apathy 

 which causes them to remain quiet, seemingly almost 

 paralyzed, and ruffle up the feathers. The eyes are 

 closed shortly after the illness begins, and the birds 

 gradually fall into a stupor from which they do not 

 awaken. The disease leads to a fatal termination in 

 twenty-four to forty-eight hours. During its course 

 there is profuse diarrhea, the very frequent fluid, slimy, 

 grayish-white discharges containing numerous micro- 

 organisms. 



The bacilli which are responsible for this disease were 

 first observed by Perroncito in 1878, and afterward thor- 

 oughly studied by Pasteur. They are short, broad bacilli 

 with rounded ends, sometimes united to each other, 

 with the production of moderately long chains (Fig. 105). 

 Pasteur at first regarded them as cocci, because when 

 stained with a penetrating anilin dye the poles stain 

 intensely, but a narrow space between them remains 

 almost uncolored. This peculiarity is very marked, and 

 sharp observation is required to observe the outline of 

 the intermediate substance. The bacillus does not form 

 spores, and does not stain by Gram's method. When 

 examined in the living condition it is found to be motile. 



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