ii6 



FOWL TYPHOID 



day and external symptoms about the fifth, or sixth, occa- 

 sionally 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 symp- 

 toms following the intravenous injection of the virus were, as 



Fig. r6. Temperature chart of two fatal cases artif daily 

 produced in fowls. 



would be expected, considerably modified from those fowls 

 which contracted the disease by the ingestion of cultures of the 

 specific bacterium. 



§ 105. 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 

 feebly. Not infrequently the cells are isolated and their out- 

 lines indistinct. Occasionally foci are observed in which the 

 liver cells appear to be dead and the intervening spaces infil- 

 trated with round cells. The changes in the hepatic tissues 

 are presumably secondary to the engorgement of the organ 

 with blood. 



The rareness with which the intestinal tract is affected in 

 both the natural and artificially produced cases is exceedingly 



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