MORBID ANATOirY II7 



interesting and important for the differential diagnosis. There 

 is in most cases a hyperemia of the mucous membrane of the 

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

 vidual. The kidneys 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 kidneys 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 were 

 not appreciably enlarged in any individual examined. The 

 lungs except in chronic cases are normal. The brain and 

 spinal cord are unaffected. 



The heart muscle is usually pale and sprinkled with gray- 

 ish points, due to cell infiltration and necrosis. These lesions 

 are so common that it seems safe to consider them character- 

 istic manifestations. Death usually occurs in systole, the 

 auricles containing very thin, unclotted blood. 



The most important alterations are found in the blood. 

 These consist, in the progress of the disease, of the gradual 

 disappearance of the red corpuscles and increase in the number 

 of white ones, as determined by blood counts made daily or 

 every other day, from the time of inoculation, or of feeding 

 the virus, until the day of death. 



The diminution in the number of red corpuscles and the 

 increase in the number of white ones are illustrated in the 

 blood count of two cases of artificially produced disease. 



In carefully heated cover-glass preparations of healthy 

 fowl's blood stained with methylene-blue and eosin, the nuclei 

 are colored a deep blue, and the cellular protoplasm surround- 

 ing the nucleus is stained by the eosin. In similar prepara- 

 tions made from the blood of the afi"ected fowls there are a 

 greater or less number of cells which do not take the eosin 

 stain. These were called spindle cells by Van Reckling- 

 hausen, blood plates by Bizzozero, and hematoblasts by 

 Hayem. More recently Dekhuyzen has called them throm- 

 bocytes. In these the portion of the cell body surrounding 



Digitized by Microsoft® 



