1 94. Veterinary Medicine. 



season. In this respect chicken cholera agrees with Asiatic, 

 cholera, typhoid fever and other affections in which the virus 

 abounds in the alvine discharges, The sale and transportation of 

 the guano from the infected poultry yard is a direct cause of new 

 outbreaks. Feeding on the carcasses or offal of the infected birds 

 is a further cause. It must not be forgotten that the microbe is 

 largely saprophytic, living indefinitely in the organic matter in 

 soils, and determining new outbreaks when brought in contact 

 with susceptible animals. Thus a period of immunity may be 

 followed by infection when new birds are brought in or when 

 young and susceptible ones grow up. 



Susceptible Animals. Fowl cholera is preeminently a disease 

 of chickens, but the microbe is successfully transferred to pigeons, 

 peafowl, pheasants, parrots, ducks, canaries, sparrows and other 

 small birds, also to Guinea pigs, rabbits, white and gray mice. 

 The Canadian form is deadly to turkeys (Higgins). Guinea 

 pigs have abscesses in the seats of inoculation (Pasteur) ; the 

 same is alleged of sheep and horses (Kitt), and man (Mar- 

 chiafava, Celli). Injection into a cow's teat caused chronic 

 catarrhal mammitis in which the microbe persisted for a long 

 while (Kitt). Like other members of the group of microbes 

 causing septicaemia hemorrhagica, the pathogeny and even the 

 morphology are liable to material modification as grown in 

 different environment (genera). In the Canadian as compared 

 with European epizootics there were the following differential 

 features : — The bacterium was smaller ; several were often con- 

 nected together ; they grow more slowly in gelatine cultures (Col- 

 onies not before the 3d day); they were more easily destroyed by 

 solutions of carbolic acid (1:100 in 5 minutes); they developed 

 acid with dextrine and lactose ; they caused earlier deaths (birds 

 sometimes perishing in 3 hours), (Higgins). Some of the forms of 

 cholera occurring among domesticated birds and held to be dis- 

 tinct diseases may find in this an explanation. Rabieaux claims 

 that under favorable conditions it has been transmitted to the frog. 



Incubation. This varies from 18 to 48 hours, the usual being 

 24 hours. 



Symptoms. In some, fulminant cases the animal is found dead 

 a few hours after apparently blooming health ; it may even have 

 died on the nest or fallen dead from the roost. Cadeac speaks of 



