NEUROLVMPHOMATOSIS IN CHICKENS 5 



not clestro\ed, and the nourishment in the \ascuiar s\ stem was diverted from 

 the nerve fibers to the pathological cells, which appeared to increase very rapidly 

 b\- further infiltration and mitosis until all of the neutral staining tissues were 

 replaced b>' basic staining neoplastic cells. In other words, the nerve fibers 

 appeared to die for the lack of nourishment and were finally dissolved and carried 

 away by the blood stream, as the pathological cells at first surrounded them 

 and later replaced them entirely. This is the physiological development of the 

 neurohmphoma in the nerve of the fowl as obser\'ed histologicalh- in these studies. 

 Enzymes ma\- have pla\ed a part in the destruction and absorption of the nervous 

 tissue, but their presence could not be demonstrated in either living or dead 

 tissues. 



This tumor-like growth of the ner\-ous system is what Pappenheimer et al. 

 (1929) have called a neurohmphoma, and it leads to the pathological condition 

 called neurohmphomatosis b\' Johnson (1932). These names are retained in 

 this stud>' and ha\e alread\' been used se\eral times. Since the neurohmphoma 

 tissue cannot be stimulated like nervous tissue, it natural!)' follows that muscles, 

 organs, and other structures supplied b\- nerves sufTer as a result of interference 

 in normal functions, and symptoms of disease arise. 



Figure 3. Lymphocytoma of the Gizzard. 

 Left, diseased gizzard. 

 Right, normal gizzard. 



The fact that the neoplastic cell in\ohed in neurohmphomatosis has been found 

 in the blood and hmph shows that there is ample opportunity- for it to find its 

 \va\- into the general circulation and be in\ohed in metastatic conditions. Metas- 

 tasis, as well as infiltration, has been found in this stud\- and will be pointed out 

 a little later. 



Before proceeding further it is necessary to indicate that the neurohmphoma 

 resembles the lymphocytoma in physical appearance and consistency, as well 

 as in possessing the same t\pe of pathological cell. Both develop from incipient 

 perivascular infiltrations into the tissues. In advanced cases the neurohmphoma 

 is usually smaller than the lymphocytoma. This is probably due to the fact 

 that the blood and lymph spaces in the visceral organs and muscles are larger 

 than in the nervous tissues, and growth proceeds more rapidh' because more 

 cells are able to crowd in and nourishment is more readih' brought to them. 

 L\ mphocxtcma of the gizzard is shown in F"ig. 3. In adx'anced cases of hmipho- 

 cytomatosis, in which the neoplasms had reached comparatively large sizes, 

 anemia was present. Neuroh mphcmatosis was never accompanied by noticeable 

 symptoms of anemia unless the birds were so parahzed that the\' could not reach 



