NEUTRON EFFECTS ON ANIMALS 



81 



The neutron source, method of measurement, method of exposure of the 

 animals, etc. are described by Enns et al. (22). 



RESULTS 



The ribonucleinase content of the blood and tissues of normal and 

 neutron-treated rabbits is shown in Table I. 



TABLE I 



The Ribonucleinase Content of the Blood, Spleen and Bone Marrow of Neutron-Treated 



Rabbits 



* 3 to 8 rabbits were used for determining the range of normal values. 



DISCUSSION 



The data for normal rabbits, as well as for rats, have been discussed (9) 

 and compared with the data obtained by Bain and Rusch (8) for the ribo- 

 nucleinase in the pancreas and spleen of the rat. 



The ribonucleinase content of the spleens of the neutron-treated rabbits 

 is on the low side of the normal range but the deviation is not significant. 

 The ribonucleinase in the bone marrow of the neutron-treated rabbits, 

 however, has decreased significantly, with the exception of No. 2 rabbit, 

 being only three-ciuarters to one-eighth of the lowest value in the normal 

 range. This decrease is probably correlated with the decreased production 

 of the cellular elements of the blood by the bone marrow after irradiation. 

 The measurements of the blood ribonucleinase in normal animals show 

 that this enzyme accompanies the cellular elements of the blood (9). In 

 the case of the ribonucleinase in the blood of the neutron-treated animals 

 the results with four of the animals were within the normal range. The 

 blood of two rabbits (Xos. 5 and 9) contained only a negligible amount of 

 this enzyme. This finding was not surprising for rabbit No. 9, for the 



