174 Manual of Veterinary Microbiology. 



coming from a diseased chicken kills it in twenty- 

 four hours. Hence, it is a delicate reagent for veri- 

 fying the nature of an epizootic of fowl cholera, but, 

 in order that this experiment should be of real value, 

 it is evidently necessary to carefully avoid all causes 

 of error which may result from the intervention of 

 foreign germs. The blood of the rabbit which suc- 

 cumbs under such conditions is exceedingly rich in 

 the specific germs. The rabbit can also be infected 

 by way of the digestive canal. 



Inoculation of a drop of blood from a diseased 

 chicken in the subcutaneous cellular tissue of the 

 guinea pig causes an abscess which heals by evacua- 

 tion of the pus ; but inoculation into the blood results 

 in death, the same as in the rabbit and chicken, by 

 blood asphyxia. The pus of the abscess, in the 

 guinea pig, is rich in microbes and its inoculation to 

 chickens or to the rabbit reproduces the disease. 



It appears from a number of observations that the 

 contact of virulent blood or of a culture with a 

 wound can occasion in man, also, the formation of an 

 abscess, and that the cat and the dog may consume, 

 with impunity, chickens which have died from the 

 disease. 



Etiology and pathogeny. — The germ of chicken chol- 

 era is deposited on the soil of poultry houses and 

 yards with the fluid dejections of diseased fowls; 

 their entrance into the organism of healthy subjects 

 takes place by way of the digestive canal, the fowls 

 taking up particles contaminated with the germs 

 along with their food. The transmission of the dis- 

 ease by ingestion has, moreover, been experimentally 

 proved. Since desiccation and contact with the air 



