NEUTRON EFFECTS ON ANIMALS 



53 



The graph shows that no significant difference in either population or rate 

 of growth could be observed following exposure to 200 integron divisions 

 of neutron bombardment. 



CAM 



r 



CBDO 



TIME IN HOURS 

 5 6 7 



L 

 O 

 G 



C 



E 

 L 

 L 

 S 



/ 



c 

 c 



1 2 



CONTROL - 

 AIRC570N)^ 



CONT ROL — 

 WAXC480N>- 



^ 



3 



-i- 



Fig. 5. Growth of organisms irradiated during early part of resting phase. 



(A) Age in hours of culture from which irradiated and control samples were 



taken 



(B) Age in hours of subculture planted with organisms exposed to 570 n with- 



out wax shielding 



(C) Age in hours of subculture planted with organisms exposed to 480 n in 



10 in. wax ball. 

 The light dotted line indicates the probable course of development of the original 

 culture in the small sample tubes prior to exposure. In this experiment, organisms 

 exposed without wax were irradiated during active multiplication, while the organ- 

 isms exposed in wax had reached full development before bombardment. 



In experiments such as the one illustrated it was necessary to bombard 

 the two samples separately, since the slow neutrons produced in the wax 

 would find their way to the "air" sample to some extent, and reduce its 

 value as a control. This meant that it was necessary to hold one sample 

 for some little time after bombardment before transplanting, in order to 

 plant all three samples simultaneously. 



Fig. 5 represents an experiment in which we sought to overcome this 



