42 BIOLOGICAL EFFECTS OF RADIATION 



of matter: they merge with negative electrons, and the two oppositely- 

 charged electrical particles which combine in such a merger are converted 

 into one or two particles of light. A portion of the reduction in intensity 

 which a beam of high-energy gamma rays suffers in traversing a stratum 

 of matter is due to the first of these processes, and a portion of the 

 "scattered" radiation arises from the second. 



Manuscript received by the editor September, 1934. 



