552 PATHOGENIC MICROORGANISMS 



and the Bacillus pleurosepticus which causes an acute disease in 

 cattle and often in wild game. 



Because of certain cultural and pathogenic ^characteristics, it 

 seems best to consider the bacillus of bubonic plague with this group. 



BACILLUS OF CHICKEN CHOLERA 



(Bacillus avisepticus) 



The bacillus of chicken cholera was first carefully studied by Pas- 

 teur * in 1880. It is a short, non-motile bacillus, measuring from 0.5 to 

 1 micron in length. Stained with the ordinary anilin dyes, it displays 

 marked polar staining qualities, which often give it the appearance of 

 being a diplococcus. It is decolorized by Gram's method. It does not 

 form spores, but may occasionally form vacuolated degeneration forms, 

 not unlike those described for Bacillus pestis. 



The bacillus is easily cultivated from the blood and organs of infected 

 animals, it grows well upon the simplest media at temperatures vary- 

 ing from 25 to 40 C. In broth, it produces uniform clouding with 

 later a formation of a pellicle. Upon agar it forms, within twenty-four 

 to forty-eight hours, minute colonies, white or yellowish in color, which 

 are at first transparent, later opaque. Upon gelatin, it grows without 

 liquefaction. Upon milk, the growth is slow and does not produce co- 

 agulation. According to Kruse, 2 indol is formed from pepton bouillon. 

 Acid, but -no gas, is formed in sugar broth. 



Among barnyard fowl, this disease is widely prevalent, attacking 

 chickens, ducks, geese, and a large variety of smaller birds. The infection 

 is extremely acute, ending fatally within a few days. It is accompanied 

 by diarrhea, often with bloody stools, great exhaustion, and, toward the 

 end, a drowsiness bordering on coma. Autopsy upon the animals re- 

 veals hemorrhagic inflammation of the intestinal mucosa, enlargement 

 of the liver and spleen, and often bronchopneumonia. 



The specific bacilli may be found in the blood, in the organs, in exu- 

 dates, if these are present, and in large numbers in the dejecta. Infection 

 takes place probably through the food and water contaminated by the 

 discharges of diseased birds. 3 



Subcutaneous inoculation or feeding of such animals with pure 

 cultures, even in minute doses, gives rise to a quickly developing 

 septicemia which is uniformly fatal. The bacillus is extremely patho- 



1 Pasteur, Comptes rend, de 1'acad. des sci., 1880. 



2 Kruse, in Fltigge's " Die Mikroorganismen." 



3 Salmon, Rep. of the Com. of Agriculture, 1880, 1881, and 1882. 



