effects of exposing seeds 95 



Experiment io 

 March 23, 4:30 P. M. 



The experiment was set up as in No. 9, only a sealed glass tube 

 containing radio-tellurium was used instead of the radium tube. 

 Timothy seed was employed. 

 March 30, 3 145 P. M. 



The seedlings in both cultures have an average height of about 

 25 mm., except those immediately under the tube of radio-tellurium, 

 which are only about one half as tall as the others, but the influence 

 has not extended to any appreciable distance from the tube in any 

 direction. The tube was in contact with the underlying seeds. 



Experiment ii 

 May 12, 6 P. M. 



Eight seeds of the bean {Phaseolus) were placed, four in a row, on 

 moist sphagnum, with the hilum-edges adjacent. Over them, rest- 

 ing on the adjacent edges, was placed the coated rod (10,000 x). 

 Eight dry seeds were similarly exposed. 

 May 14, 12 : 30 P. M. 



After 42 hrs. exposure, the seeds, together with eight unexposed 

 seeds, were planted in soil. 

 May 26, 9 A. M. 



The seeds in all three cultures germinated poorly, but of those 

 exposed while imbibing water, only one has come up, of those ex- 

 posed dry, five have come up with an average length of hypocotyl 

 above the surface of the soil of 39.60 + mm. Four, only, of the 

 control seeds came up, but the average length of their hypocotyls 

 above the soil surface is 59.25 mm. The hypocotyls of those ex- 

 posed dry, and of the control seeds were preserved for histological 

 study. (See p. 226.) 



Experiment 12 

 May 14, /| P. M. 



On damp cotton in a moist chamber were placed 8 seeds of the 

 bean {Phaseolus), in two rows of 4 seeds each, with the hilum edges 

 of opposite seeds adjacent. The radium-coated rod (25,000 x) was 

 placed in contact with the adjacent edges. 



Control of 8 seeds in the same chamber, but with no radium. 

 May 19, 9 A. M. 



All the seeds have germinated in both cultures. The lengths of 

 the radicles are as follows : 



