DISEASES OF THE DIGESTIVE TRACT 81 



appearance of the first symptoms of the disease) 

 is given as from twelve to forty-eight hours. 



In our experimental work, in which the virus 

 (germ) was introduced into the peritoneal cavity 

 this period was six to twelve hours; when the 

 virus was given by the mouth it required twenty- 

 four to thirty-six hours to produce the disease. 

 The birds died twelve to seventy-two hours later. 



Symptoms. — The onset of this disease may be 

 so sudden that its signs pass unobserved, and 

 finding the dead birds in the nests or under the 

 roosts may be the first notice that the owner has of 

 the existence of disease in his flock; or the birds 

 may have fowl cholera in a more chronic form 

 and live for six to seven days. 



In the protracted cases there is noted loss of 

 appetite, great prostration, staring feathers; the 

 bird mopes or sits around with tail and head down, 

 giving so-called "ball" appearance, the comb is 

 dark, the gait swaying, and there is trembling, 

 convulsions, thirst, and severe diarrhea, with pas- 

 sages of a greenish-yellow color. There is high 

 fever and the bird rapidly becomes emaciated. 



The percentage of loss in the flock, if jnot 

 treated, is very great. The disease spreads rap- 

 idly through a flock. Pure-bred birds are more 

 susceptible than scrubs. In an outbreak of cholera 

 among ducks, studied in the author's laboratory, 

 the disease progressed very slowly. Only one 

 to five or six ducks died in the course of a week 

 in the flock of 500. 



Postmortem Findings.— Upon opening the abdom- 

 inal cavity one will first note that the liver is 

 greatly enlarged, very dark in color and tears 

 easily (inflammation, congestion and cloudy swell- 

 ing) ; we have found livers that weighed as much 



