NEUTRON EFFECTS ON ANIMALS 77 



change in concentration was applied, the negative vahies approached zero, 

 as reported in Table I. The only other value subject to the catalase error 

 is that for irradiated rabbit No. 2, which would be slightly higher if cor- 

 rected. 



The catalase activity of the washed marrow from the irradiated rabbits 

 studied was as high as that of the untreated rabbits. This was true even 

 in the case of irradiated rabbit Xo. 1 , where the peroxidase activity had been 

 reduced to zero. In the case of dogs, however, the values for the irradiated 

 animals were considerably lower than for the two untreated dogs studied. 



DISCUSSION 



The existence of peroxidase in animal tissues has been doubted by many 

 authors. Bancroft and Elliott (4), however, gave evidence of the proba- 

 bility of its occurrence in small amounts in spleen and lung. Dempsey (5) 

 reported it in tissue of thyroid gland, but Glock (6) gave evidence that this 

 activity could be accounted for by the hemoglobin content. It is know^n 

 to occur in considerable quantity in the animal, however, in white blood 

 cells of the granulocyte series (7) and in milk (8). The hnding of con- 

 siderable amounts of peroxidase in bone marrow in the present study can- 

 not be due to the presence of hemoglobin, since this was completely re- 

 moved by washing. Its presence is most probably due to the presence of 

 white blood cells which are normally found in bone marrow. 



Radiation with X-rays and with neutrons is known to produce an early 

 and sharp diminution in the number of white cells present in the blood 

 (9, 10) and in the bone marrow (-11, 12). It is reasonable to suppose,, 

 therefore, that a lack of white blood cells in the marrow accounts for the 

 absence of peroxidase in the six cases reported in Table I. It will be noted 

 that in five of these cases the white cell count in the blood was exceedingly- 

 low. The presence of this small number of white cells in the blood may 

 possibly be accounted for by production in other marrow which was not 

 investigated in the present study. 



SUMM.\RY 



Peroxidase has been found to be absent from the marrow of leg bones of 

 rabbits and dogs at or near death as a result of neutron radiation. In: 

 animals whose health was not materially affected by the radiation, the 

 peroxidase values were in the same range as those found for untreated 

 animals. 



Catalase activity of the marrow from rabbits did not appear to have been 

 affected, while in dogs the activity appeared to be decreased as a result of 

 the radiation. 



