no 



EFFECTS OF EXPOSING SEEDS 



soaked seeds were exposed for 15 hrs. (1,500,000 x ), was followed 

 by a recovery and apparent acceleration of growth, for the plants 

 from exposed seeds, within ten days after planting, had caught up 

 with and even slightly surpassed the control plants in height. The 

 effect of this exposure of the white mustard was slight, and in har- 

 mony with results obtained by Koernicke,* who found Brassica nafiis 

 especially resistant. He reported that swollen seeds were accelerated 

 in growth by exposure to 10 mg. of radium bromide, but does not 

 state the activity of the preparation he used. 



When seeds of Ltcpinus albus were first soaked in water, and then 



12 0. 



11 12 



Day of month 



Fig. 10. Effect on the Growth of Zea Mays of Exposing the Grains, before Plant- 

 ing, for 16 Hours, to Raj'S from Radium of Different Degrees of Activity. 



exposed while germinating for 18 hrs. (10,000 x ), and planted in soil, 

 the tap-roots grew very abnormally. After 16 days' growth in the 

 soil the tap-roots had evidently ceased growing, and, correlated with 

 this fact, the secondary roots had developed more vigorously than 

 normally. 



Oat grains were exposed for 67 hrs. after being soaked in water, 

 and then planted in soil. The subsequent growth of the shoots was 



♦Bibliography, p. 72, No. 39. 



