8 MASS. EXPERIMENT STATION BULLETIN 39 L 



Table 4. — Lymphocytoma: Correlation of Quarter of Year at Necropsy 



AND Type of Disease. 



Figures represent percent of cases occurring in the respective quarters of the year. 

 Figures in parentheses are number of cases in the group. 



No Nerves Involved Nerves Involved Total 



Form of 



Tumor 1* 



Diffuse.... 23.9 22.4 25.4 28.3 33 3 11.7 27.5 27.5 28.0 17.8 26 2 28.0 



(16) (15) (17) (19) (17) (6) (14) (14) (33) ,21) (.31) (33) 



Nodular... 33.3 22.2 16.6 27.9 — — 50.0 SO.O 30.0 20.0 20.0 30.0 



(6) (4) (3) (5) — — (1) (1) (6) (4) (4) (6) 



30.0 16.6 36.8 16.6 33 3 12.0 18 7 36.0 



(9) (5) (11) (5) (25) (9) (14) i27) 



Total... 29.2 17.7 17.7 35.4 31.4 13.2 31.4 24.0 30.0 16.0 23.0 31.0 



(38) (23) (23) (46) (26) (11) (26) (20) (64) (34) (49) (66) 



*1 indicates first quarter of year including months of January, February, and March; 

 2 indicates the following three months: and so on for 3 and 4. 



Distribution of Lesions. — In the group of cases studied, lymph&c\ toma was 

 found to affect nearly every organ or tissue in the chicken. The order in fre- 

 quenc\- of involvement was as follows: liver, gonad, kidne\', spleen, nerve, peri- 

 toneum, adrenal, intestine, marrow, lung, pancreas, heart, bursa of Fabricius, 

 proventriculus, skeletal musculature, skin and subcutis, thymus, thyroid, 

 parathyroid, and oviduct (Table 5). 



The arrangement of lymphocytomas into groups according to type led to 

 interesting results in connection with the distribution of lesions. The tumor, 

 when nodular in form, was found to be confined to fewer organs and to affect 

 certain organs more frequently than others. In the 20 cases of nodular lympho- 

 cytoma, the liver was involved in 18 (90 percent) and the spleen in 17 (85 per- 

 cent). The kidney, gonad, lung, thymus, adrenal, intestine, and proventriculus 

 were more frequently affected in cases of combined diffuse and nodular lympho- 

 cytoma than in the other forms of the disease. The marrow, peritoneum, skin 

 and subcutis, musculature, heart, pancreas, and bursa of Fabricius were involved 

 about as often in the diffuse type of lymphocytoma as in the combined diffuse 

 and nodular lorm. (Chart 1.) 



Certain differences in the frequency of organ involvement were apparent 

 between those cases in whi.^h nerves were also affected and those in which nerves 

 were not affected. The liver, spleen, kidney, marrow, and bursa of Fabricius 

 were more frequently affected in those cases of lymphocytoma with no nerve 

 infiltration. The lung, peritoneum, skin and subcutis, musculature, adrenal, 

 heart, and proventriculus were more commonly affected when nerves were in- 

 filtrated. In some instances (liver, spleen, and adrenal) the difference was marked. 

 Essentially similar differences were noted when the respective types of lympho- 

 cytoma with and without nerve involvement were compared as when the entire 

 group of cases was separated on the basis of infiltration of nerves only and com- 

 pared as is done in Tables 5 and 6. 



The nerve tissue most commonly involved with Ismphocytoma was that in. 

 the region of the anterior mesenteric plexus. Other sites frequently infiltrated 

 with the tumor are listed in Table 5. 



