NEUTRON EFFECTS ON ANIMALS 



109 



globulin. The variations in total concentration were largely a reflection of 

 variations in the concentrations of fibrinogen plus gamma globulin. 



GROSS PATHOLOGY 



Only chicken 22 showed gross pathological changes of significance. The 

 heart was dilated, and the walls were thin. This hypertrophy may be 

 attributed to anemia resulting from the repeated bleedings. An adhesion 

 between the pericaidial sac and the heart may likewise have been due to 

 the bleeding. The spleen appeared to be slightly reduced in size. The 

 bone marrow was very red. All other tissues appeared normal. 



40 



X 



20 



20 



40 



60 



DAYS 



Fig. 6. Composition of successive samples of plasma from non-irradiated chickens. 

 Ordinates: concentrations expressed in refractive increments X 10*. Abscissae: 

 days after irradiation. Chicken 69: O; chicken 80: D. Upper graphs: concen- 

 tration of albumin. Lower graphs: concentration of alpha globulin plus beta glo- 

 bulin. 



DISCUSSION 



The lymphocytes are a storehouse of readily available gamma globulin 

 which can be released either through dissolution of the lymphocytes by 

 adrenal cortical stimulation, or through direct destruction of the lympho- 

 cytic elements without hormone mediation (9). Neutron irradiation 

 inhibits production of lymphocytes, and the lymphocytes already in circu- 

 lation are either destroyed or gradually lost (10). In the chicken pro- 

 duction of lymphocytes was found in this Laboratory to be resumed on 

 the third day following neutron irradiation. 



Because of the small number of animals examined in this study, definite 

 conclusions are hardly warranted. It may be pointed out, however, that 



