MORBID ANATOMY lOI 



would be expected, considerably modified from those in fowls 

 which contracted the disease b^^ the ingestion of cultures of 

 the specific bacterium. 



§ 87. 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 in- 

 spection shows the surface to be sprinkled with minute grayish 

 areas. The microscopic examination shows the blood spaces 

 to be distended. The hepatic cells are frequently changed, so 

 that they stain very feebly, and not infrequently the cells are 

 isolated and their outlines indistinct. Occasionally foci are 

 observed in which the liver cells appear to be dead and the in- 

 tervening spaces infiltrated with round cells. The changes in 

 the hepatic tissue are presumably secondary to the engorge- 

 ment of the organ with blood. 



The rareness with which the intestinal tract is affected in 

 both the natural and artificially produced cases is exceedingly 

 interesting and important for the differential diagnosis. There 

 is in most cases a hj'persemia of the mucous membrane of the 

 colon, but this condition is not uncommon in the healthy indi- 

 vidual. The kidnej-s are generally but not uniformly pale. 

 They are streaked with reddish lines, due to the injection of 

 blood vessels. In section the tubular epithelium appears to be 

 normal. The kidnej^s seem to be, from the number of bacteria 

 in the cover-glass preparations, especially favorable for the 

 localization of the specific organism. The spleen is rarely dis- 

 colored or engorged with blood. The lymphatic glands are 

 not appreciably enlarged in any individual examined. The 

 lungs except in chronic cases are normal. The heart muscle 

 is usually pale and sprinkled with grayish points, due to cell 

 infiltration and necrosis. These lesions are so common that it 

 seems safe to consider them characteristic manifestations. 

 Death usually occurrs in systole, the auricles containing very 

 little thin, unclotted blood. The brain and spinal cord are 

 unaffected. 



The most important alterations are found in the blood. 

 These consist of the gradual disappearance of the red cor- 



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