NEUTRON' EFFECTS ON ANIMALS 83 



in the desoxyriboniicleic acid as discussed above to disturV) its function 

 in the cell. The studies (28) which have shown that desoxyribonucleic 

 acid is probably the factor determining the specific type of the pneumococci 

 suggest a high degree of specificity of the desoxyribonucleic acids. Since 

 chemical studies so far have not revealed any differences, this specificity 

 may well reside in physical arrangement of the molecule. .\ specific orien- 

 tation of the molecule might readily be disturbed by irradiation with conse- 

 quent deep seated disturbance of cellular di^•ision. 



The large amount of evidence that the nucleus of the cell and the nuclear 

 (desoxyribo-) and cytoplasmic (ribo-) nucleic acids are closely involved 

 in the effects of X-rays and neutrons on the cell emphasizes the importance 

 of research on these constituents. Hypothetical mechanisms for the inter- 

 action of ionizing rays and the nucleic acids suggest paths to be investigated. 



SUMMARY 



The ribonucleinase content of the blood, lione marrow and spleen of 

 neutron-treated rabbits was determined and compared with the values 

 obtained with normal rabbits. Significant reductions occurred in the bone 

 marrow and in a few cases extremely low values were found in the blood. 

 In no case, however, did the effect appear to l)e a prim.ary one. 



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