60 



NEUTRON EFFECTS ON ANIMALS 



adventitious roots on 17 per cent of the seedlings (Table I). In this ease 

 the primary root had reached a length of only 19 mm. before death, as 

 compared with 30 mm. in the X-rayed plants. 



C 200 



TIME IN HOURS 



Fig. 1. Growth curves of primary roots after doses of neutrons up to 80,000 n 



This was one case where a dose of neutrons sufficient to kill the plant 

 had less effect on one kind of tissue than a killing dose of X-rays if these 

 results with neutrons are compared with those of Smith and Kersten (8) 



