EFFECTS OF EXPOSING SEEDS lOI 



September 19. 



The plants were photographed together with those of Experiment 

 14, and portions of the hypocotyls and roots were preserved for sec- 

 tioning (figure 7). The radium rod was continued throughout 

 the experiment. 



Experiment 18 



Object : To ascertain the effect of the rays from a radium-coated 

 rod on the germination and growth of Lu^inus albus. 



June 16, 3 P. M. 



Eight seeds of Ltipinus albus were placed in two parallel rows in 

 moist sphagnum, with a rod coated with Lieber's "radium-coating" 

 (about 10,000 X , and one year old) placed in contact with the hilum- 

 edges of the seeds. 



Eight control seeds similarly placed, but with no radium. 



June 20, 3 P. M. 



The lengths, of the hypocotyls from the cotyledons measured as 

 follows : 



Acceleration of growth has followed exposure to the rays. 



Experiment 19 



Five seeds of Henderson's "Long Yellow Six Weeks" bean 

 {Phaseolus) were exposed for five days (120 hours), during imbibition 

 from the dry condition, to a radium-coated rod (10,000 x). 



At the end of the 120 hours the hypocotyls of the exposed seeds 

 averaged 50.80 mm. in length, those of the control seeds 56.00mm. 

 Portions of the root and hypocotyl of the exposed seeds and of con- 

 trol specimens were preserved for sectioning (p. 226). 



