I04 EFFECTS OF EXPOSING SEEDS 



seeds each, and placed to germinate in the Zurich germinators ; 7? 

 with the radium-tube (1,500,000 x) lying over and in contact with 

 the seeds, C with a short glass rod lying over the seeds. 



December i, 8 130 A. M. 



In R three radicles have protruded, in C four. The seeds were 

 placed to develop further in two pots of earth of equal size. 



December 18, 12 M. 



In the radiated culture four arched hypocotyls are above the sur- 

 face of the soil ; in the control culture, six. 



January 2, 9 : 30 A. M. 



Radium Control 



Onlv 5 seeds have germinated. Seven seeds have germinated. 



Lengths of hypocotyls above surface Lengths of hypocotyls above surface 



of soil as follows : of soil as follows : 



35.00 mm. 7S.00 mm. 



23.00 90.00 



14.00 90.00 



9.00 69.00 



5.00 65.00 



86.00 mm. 392.00 mm. 



Average, 17.20 mm. Average, 78.40 mm. 



The petioles of the cotyledons in C were longer than those in 7?, 

 and the seedlings were in ever}^ way more vigorous and healthy. 



Experiment 22 

 January 5, 9 A. M. 



Six flax seeds {Lmum)^ soaked in water over night, were placed 

 in Zurich germinators, and the glass tube of RaBr2 (1,500,000 x) 

 was laid over them, with the radium evenly distributed along the 

 bottom of the tube. 



Control, similarly arranged with an empty glass tube, and both 

 cultures placed in the dark room. 



January 6, 2 P. M. 



None of the seeds have germinated. 

 January 7, 9 A. M. 



All of the seeds under the radium have germinated ; all but one 

 of the control seeds. 



An exposure of 48 hrs. to the RaBr2 of 1,500,000 activity has 

 not been sufficient appreciably to affect germination. 



