DIFFERENTIAL DIAGNOSIS 



105 



In the blood from healthy fowls it is coraparativeh' rare to- 

 see one of the white corpuscles attacking a red one. As the 

 disease progresses, however, this warfare becomes very con- 

 spicuous, owing perhaps to the increased number of the color- 

 less cells. Up to the present the study of these corpuscles has 

 not been extended beyond the observation of the general ap- 

 pearance of these structures, and no attempt is made to explain 

 the apparently marvelous increase in the number of the leuco- 

 cytes. It is an interesting and as j^et unexplained fact that 

 the increase in the white corpuscles is apparently restricted to 

 those containing the spindle-shaped bodies. 



§ 88. Differential diagnosis. Intestinal disturbances, 

 especially diarrhoea and fowl cholera, are the diseases liable to 

 be mistaken for infectious leukaemia. 



A comparison of the important changes in the morbid 

 anatomy in fowl cholera as described by European writers 

 and in the disease under consideration can be made from the 

 appended columns, in which their more characteristic lesions 

 are contrasted : 



Lesions in Foivl cholera. 



1. Duration of the disease from a 



few hours to several days. 



2. Elevation of temperature. 



3. Diarrhoea. 



4. Intestines deeply reddened. 



5. Intestinal contents liquid, 



mucopurulent, or blood 

 stained. 



6. Heart dotted with ecchy- 



moses. 



7. Lungs affected, hyperaemic or 



pneumonic. 



8. Specific organisms appear in 



large numbers in the blood 

 and organs. 



9. Blood pale (cause not deter- 



mined). 



ID. Condition of leucocytes not 

 determined. 



Lesions in infectious leukaemia. '\ 



1. Duration of the disease from 



a few hours to several daj^s. 



2. Elevation of temperature. 



3. Diarrhoea very rare. 



4. Intestines pale. 



5. Intestinal contents normal in 



consistencv. 



6. 



7- 



•9 



10. 



Heart usually pale and dotted 

 with grayish points, due 

 to cell infiltration. 



Lungs normal, excepting in 

 modified cases. 



Specific organisms compara- 

 tively few in the blood 

 and organs. 



Blood pale, marked diminu- 

 tion in the number of red 

 corpuscles. 



Increase in the number of 

 leucocytes. 



