234 DISEASES OF POULTRY. 



usually have nothing more than an abscess at the 

 point of inoculation. 



Symptoms. — This disease as it occurs in Europe is 

 more rapid in its course and differs somewhat in its 

 symptoms from outbreaks which the author has ob - 

 served in the United States. The incubation in 

 Europe is placed at 8 to 16 hours. In the case of 40 

 fowls inoculated by the author, the average period of 

 incubation was 8 days, and it varied from 4 to 20 

 days. The virus evidently varies in its activity jn 

 this country. The duration of the disease, also, varies. 

 With the 40 cases mentioned above it averaged 3 days. 

 The sick birds generally stop eating or the appetite 

 is lessened, though occasionally they continue to eat 

 almost to the time of death. The earliest indication 

 of the disease, is a yellow coloration of the urates, or 

 that part of the excrement which is excreted by the 

 kidneys. This is in health a pure white, though it is 

 frequently tinted with yellow as the result of other 

 disorders than cholera. While, therefore, this yellow- 

 ish color of the urates is not an absolutely certain 

 proof of cholera, it is a valuable indication when the 

 disease has appeared in a flock and an effort is being 

 made to check its course by isolating birds as soon as 

 possible after infection. 



In a few cases the first symptom is a diarrhea in 

 which the excrement is passed in large quantities and 

 consists almost entirely of white urates mixed with 

 colorless mucus. Generally, the diarrhea is a prom- 

 inent symptom. The excrement is voided frequently 

 and consists largely of urates suspended in a thin, 

 transparent, sometimes frothy mucus. The urates 

 have a deep yellow color, which in the later stages of 



