192 Veterinary Medicine. 



The7(7M« from the ravages of this disease are far gre^iter than 

 the average value of the individual animal would lead one to sup- 

 pose, but with domestic fowls numbering 300,000,000 and a yearly- 

 egg crop bordering on a billion dozens it may well be -called 

 enormous. 



Bacteriology. Chicken cholera is caused by a very small ovoid 

 bacterium (B. Cholerse gallinacese, B. Avicidum) about 0.3 to 

 i.8ju.long, (0.3-ifi, Friedberger; 1-2/n, Ward), as found in the 

 blood and tissues of the fowl. It has the general characters of 

 the groups which cause hemorrhagic septicaemia, thus : i . It 

 fixes, above all at the poles, the ordinary anilin colors ; 2. It is 

 decolorized by the methods of Gram and Wiegert (iodine solu- 

 tions); 3. It grows on gelatine without liquefying it ; 4. It pro- 

 duces acute septicemic lesions ; 5. It tends to polymorphism 

 when grown under different conditions. In the peritoneum of 

 the guinea pig it forms cocco-bacilli tending in acute and violent 

 cases to diplococci. Fed to rabbits it appears in the faeces as a 

 minute bacillus. Even the mode of staining causes a difference 

 in appearance. Fixed in alcohol-ether, and then stained in Ziehl's 

 phenated preparation, coloring is polar, and the central area clear. 

 If in place of Ziehl's fluid, hot fuchsin solution is used warm for 

 Yz a minute, a bacillus or cocco-bacillus is shown (Lignieres). It 

 is nonmotile, though some observers have been misled by Brownian 

 movements. There are no flagella. In old bouillon cultures 

 short chain forms are met with. No spores are formed. 



From fresh cultures, in flask or in animals, the bacterium 

 grows readily in alkaline culture media. In bouillon a turbidity 

 ensues, and after some days pellicles form on the surface and 

 walls, and the liquid slowly clears. The addition of a little blood 

 serum, sugar or glycerine encreases and hastens the growth, 

 while acid retards or prevents. This is common also to other 

 septicsemic germs. In gelatine growth is tardy, but in two or 

 three days there are whitish glistening colonies, becoming 

 opaque later, and appearing granular if slightly magnified. In 

 punctures minute colonies form along the line of culture and one 

 at the surface, at first translucent ; later opaque. On agar the 

 colonies grow faster with similar appearance. On gelose at 37" C. 

 the colonies are bluish and iridescent, at first, and later opaque. 

 If the germ has been repeatedly passed through the Guinea pig, 

 they are more translucent. On potato with alkaline surface, 



