78 FOWL TYPHOID 
blood shows a marked diminution in the number of red corpuscles 
and an increase in the number of white. ones. In the disease pro- 
duced artificially by feeding cultures of the specific organism there 
is, in most cases, a marked drowsiness and general debility mani- 
fested from one to four days before death occurs. The period during. 
which the prostration continues varies from a few hours to two days. 
The mucous membranes and skin about the head become pale. There 
is an elevation of from 1 to 4 degrees in temperature. The fever is of 
a continuous type, as shown in the appended temperature chart of 
two fowls in which the disease was produced artificially. 
Although the course of the disease in different fowls is usually 
constant, there are many variations. The time required for fatal 
results is from three to fifteen days, but ordinarily death occurs in 
about eight days after feeding the cultures. The rise in temperature 
can be detected about the third day and external symptoms about the 
fifth or sixth, occasionally not until a few hours before death. The 
symptoms observed in the cases produced by feeding correspond with 
those described by the owners of affected flocks. 
As indicated in the inoculation experiments, the symptoms follow- 
ing the intravenous injection of the virus were, as would be expected, 
considerably modified from those fowls which contracted the disease 
by the ingestion of cultures of the specific bacterium. 
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Fic. 7. TemMprerRaATURE CHART OF TWO FATAL CASES ARTIFICIALLY PRODUCED IN FOWLS. 
Morbid anatomy. The only constant lesions found in the fowls 
which contract the disease naturally, as well as in those fed upon the 
virus, are in the liver and blood. The liver is somewhat enlarged 
and dark colored. A close inspection shows the surface to be sprinkled 
with minute grayish areas. The microscopic examination shows the 
blood spaces to be distended. The hepatic cells often stain very 
