19 



tables is due to the fact that the battery used in this case bad a 

 lower voltage than the one used in the first, the optimum current 

 being in each case about 3 volts. 



An average of the lengths of the radicles in all the lots of seed 

 which were treated with the oijtimum strength of current gives 3.24 

 centimeters while an average of the normals gives 2.33 centimeters 

 or an increase of 39.06 per cent by treating the seeds with the 

 electric current. 



Some of the tables seem to show that there is an optimum strength 

 of current for germination as well as for growth of radicles. This 

 optimum for germination in the first four tables is very nearly the 

 same as that for the radicles, but there is so much variation in the 

 other tables that no conclusion can be drawn upon this point. 



EFFECTS OF ELECTRICITY ON GERMINATION AND- 



GROWTH OF RADICLES (ROOTS) AND 



HYPOCOTYLS** (STEMS) 



Of White Mustard (Brassica alba, Boiss) Rape (Brassica napus^ 

 L.) and Red Clover (Trifolium pratense, L.) 



TABLES IX.— XI. 



The experiments in these tables are similar to those given in tablea 

 I. — IV. with the exception that measurements were also taken of the 

 hypocotyls, in which case it was more convenient on account of the 

 greater maturity of the hypocotyls, to make the measurements at 

 the end of 96 hours instead of at 72 hours as in the previous tables. 

 In the following three tables the average lengths in centimeters of 

 the hy,jocotyls are given, having been determined in the same 

 manner as were the lengths of the radicles. 



**The term Hypocotyl is used by botanists to indicate tliat portion of the sten^ 

 below the cotyledons or seed leaves, see Figs. 10-11 and 12. 



