NEUROLYMPHOMATOSIS IN CHICKENS 



15 



Figure 9. Myeloleukosis. i Majjnificd ^Tii) diameters.) (Arrow points to myelocyte.) 

 Figure 10. Erytliroleukosis. (Magnified 420 diameters.) (Arrow points to erythroblast.) 



tion of the bone marrow showed a diminution, if not an entire absence, of mature 

 leukocytes. The red blood cells were a!wa\s reduced, the hemoglobin was low, 

 and the clotting of the blood retarded. 



j_,- Myeloleukosis was differentiated from Kmpholeukosis on the basis of the path- 

 ological cells appearing in the tissues of the birds affected with the respecti\e 

 diseases. In some cases the oxydase test was relied upon to identify- the niyelo- 

 blastic cells of the bone marrow from the cells of the hmphocytic series. A 

 large number of cells with oxydase granules appeared to be characteristic of 

 myeloleukosis just as the reverse seemed to be true of lympholeukosis. In advanced 

 cases of acute myeloblastic leukosis many of the cells may be too inunature to 

 react to the oxydase test. This difficulty did not lead to diagnostic error in this 

 study because the blood of the birds was examined at least once as soon as symp- 

 toms appeared and at other times later in the course of the disease. But some 

 difficult}' was experienced in differentiating generalized infiltration of h^mpho- 

 c>'tomas from Kmpholeukosis. Usualh- l\mphoc>-tomas appeared on gross 



