NEUROL^'MPHOMATOSIS IX CHICKENS 29 



Blain, Breusch, Forkner, aiul Klieneberger and Carl counted the eosinophilic 

 leukoc\tes with rods and eosinophilic leukoc>tes with granules separateK-, but 

 included the polymorphonuclear leukocytes without rods and granules in either 

 one or the other of these groups. Burnett and Cook and Dearst>ne recognized 

 polymorphonuclear leukcc\tes but counted the eosinophilic leukocytes with rods 

 and eosinophilic leukoc\tes with granules together. Fernstermacher did not 

 include any differential counts. The present writer distinguished the three 

 groups of leukocytes under discussion; but because of variations in counting, the 

 results secured b\- the different investigators are not comparable. 



The mast cell is rather eas\- to identif\- in the blood of the hea!th\ fowl, and the 

 variations in counts between the different investigators is probabh- no more than 

 could be expected between different groups of birds. Therefore, these results 

 are comparable. 



Blain, Breusch, Burnett. F"orkner, and Klieneberger and Carl did not distinguish 

 small from large hmphocytes as did the more recent investigators, Cook and Dear- 

 st>ne. The present writer included the monocytes with the large hmphocvtes. 

 The results of these investigations on the hniphoc\tes and monoc\tes are too 

 variable for comparison. 



Since the disagreements b\' hematologists are almost entireh' due to differences 

 in technique, their results do not invalidate the present study in which the same 

 methods were used throughout and the results secured with healthy birds are 

 comparable with those suffering from disease, but they do indicate the need for 

 uniformit}' in reporting the results of hematological studies for comparison. 



Summary and Conclusions 



1. The clinical course of neurohmphomatosis varies in individual cases, 

 iisualK- e.xtending over a period of several weeks or months. Complete recover^' 

 is rare. Temporar\- impro\'ement ma\- occur followed by relapse and death. 



2. Blood counts indicate that the disease begins with leukoc\tosis and 

 ends with lymphocytosis. During the period of temporar>- improxement the 

 blood ma>' be normal. 



3. The disease spreads slowl\- in affected flocks, with only a few birds becoming 

 affected at a time, but new cases continue to de\-elop until it is partialK" arrested 

 in the late fall. 



4. The morlalit\- from neurohmphomatosis is reduced after the first \ear 

 or two, although it is likel\- to reappear with each batch of new chickens for an 

 indefinite number of >ears after it is once established in a flock. 



5. Neurohmphomatosis and hmphccxtomatosis seem to be closeh' associated. 

 The former is primarih' a disease of \oung birds from 3 to 10 months of age, 

 while the latter is mere common in birds 10 months of age or older. 



6. Anemia is a symptom of hmphoc\tomatosis and leukosis and is not charac- 

 teristic of neurohmphomatosis. 



7. L\mpholeukosis is not readily differentiated from hmphocNtoniatosis. 



8. No difficult}' was experienced in differentiating neuroh nijjhoniatosis from 

 either erythroleukosis or myeloleukosis as the pathological cell is different in all 

 three diseases. 



9. The pathological cell appeared to be the same in neuroi\ niphomatosis 

 and lymphoc>tomatosis, and was characterized b\' its basic staining properties 

 and the arrangement of the nuclear and chromatin material. 



