L. A. ELSON 



of each chemical was rather more than half the toxic dose so that, had the 

 toxic effects been additive, the animals would not have survived the combined 

 treatment. No animals died, however, so that as far as total toxic effects 

 are concerned the substances act largely independendy of each other. 

 The curves for combined effects on the blood, however, are almost exactly 

 what one would expect by superimposing the curves for each chemical. 



For instance the neutroph 

 by the neutrophil-depress: 



lia resulting from CB 1348 is largely neutralized 

 ng action of Myleran and the resulting flattened 



/I 



Red cells 



Lymphocytes 



Neutrophils 



J L 



-2 2 1 6 8 10 12 11 16 18 20 ZZ 8U 26 28 



day 



Figure 5. Weight and Blood Response to Myleran + CB 1348 



hump in the curve {Figure 5) could easily correspond to the slight hump 

 observed in the radiation response curves {Figure 1). 



Further work on the combined effects of chemicals of this type is being 

 carried out and effects on the bone marrow are being investigated. The 

 results obtained so far on the bone marrow confirm the idea of the partially 

 radiomimetic effect of Myleran and CB 1348 alone and the much more 

 complete resemblance to radiation shown by a combination of the two. 



In view of these results it is tempting to speculate on the possibility as to 

 whether the effects of radiation might not be the result of two distinct 

 chemical reactions, possibly occurring simultaneously, provoked by the 



241 



R 



