92 



EFFECTS OF EXPOSING SEEDS 



February 12, ii A. M. 



The relative condition of the radiated and control sets remains as 

 yesterday. Measurements of the heights of the seedlings gave the 

 following averages at the distances indicated : 



Distance Height 



Radiujn Control 



o mm. 2.00 mm. 10.00 mm. 



5 5-00 10.00 



10 7.50 13.00 



15 11.00 14.00 



20 17.00 9.00 



25 23.00 10.00 



February 16, 3 : 30 P. M. 



All the seedlings in both cultures have apparently grown, but the 

 relative condition and size remains as on the 12th. 



Experiment 7 

 February 10, 9 : 30 x\. M. 



Experiment arranged as in No. 6, using seeds of alfalfa. 

 Februarj'^ 15, 5 : 30 P. M, 



Seeds have germinated in both cultures. In the center of the 

 radiated set germination is greatly retarded, but in the control dish 

 germination is generally uniform. 



Both cultures were placed near a window in the laboratory. 

 February 18, 11 130 A. M. 



The seedlings within a radius of 5 mm. of the radium tube have 

 not developed further than the protrusion of the radicle. All the 

 seedlings in the control culture have grown, and are taller than those 

 exposed. 



Rhizopus nigricans attacked both cultures, but while growing 

 vigorous and rank in the control culture, it grew weakly and poorly 

 in the radium culture. 

 February 22, 10 A. M. 



The leaves of the radiated seedlings are much lighter green than 

 those of the control. 



Experiment 8 

 February 26, 12 : 30 P. M. 



Unsoaked seeds of timothy grass were arranged in 8 rows, radiat- 

 ing from the center of a circular piece of blotter, which was placed 



