BY C. J. POUND, F.R.M.S. 79 



In addition to the above experiments a number of other 



rabbits and fowls were experimented on, both by feeding and 



inoculation, the results of which were highly satisfactory in 



demonstrating the nature of the disease. All the animals used 



in the foregoing experiments were well nourished and healthy, 



having previously been kept under observation for several . 



months. 



Etiology of Chicken Cholera. 



Pathogenesis. — Pathogenic for chickens, pigeons, pheasants, 

 sparrows, and other small birds ; also for rabbits and mice. 

 Subcutaneous injection of a minute quantity of a wulent culture 

 usually kills chickens within 48 hours. Some time before death 

 the fowl falls into a somnolent condition, and, with drooping 

 wings and ruffled feathers, remains standing in one place until 

 it dies. Infection may also occur from the ingestion of food 

 moistened with a culture of the bacillus or soiled with the dis- 

 charges from the bowels of other infected fowls. At the autopsy 

 the mucous membrane of the small intestine is found to be 

 inflamed and studded with small hemorrhagic foci, as are also 

 the serous membranes ; the spleen is notably enlarged. The 

 bacilli are found in great nambers in the blood, in the various 

 organs, and in the contents of the intestine. In rabbits, death 

 commonly occurs in from 16 to 20 hours, and is often preceded 

 by convulsions. The temperature is elevated at first, but shortly 

 before death it is reduced below the normal. The post-mortem 

 appearances are : — Swelling of the spleen and lymphatic glands ; 

 ecchymoses or diffuse hemorrhagic infiltrations of the mucous 

 membranes of the digestive and respiratory passages, and in the 

 muscles ; and at the point of inoculation a slight amount of 

 inflammatory cedema. The bacilli are found in considerable 

 numbers in the blood within the vessels, or in that which has 

 escaped into the tissues by the rupture of small veins. They 

 are not, however, so numerous as in some of the other forms of 

 septicaemia — for instance, anthrax, mouse septicaemia — when an 

 examination is made immediately after death ; later the number 

 may be greatly increased as a result of post-mortem multiplica- 

 tion within the vessels. The rabbit is so extremely susceptible 

 to infection by this bacillus that inoculation in the cornea by a 

 slight superficial wound usually gives rise to general infection 



