UPON ELECTRICAL STIMULI GENERALLY 53 



with the upward driving force, would appear to be the most 

 unnaturaL 



Tomatoes. 



Experiments with tomatoes gave curious results. Com 

 paratively high electrification (2 volts to a 10-inch pot 

 with negative pole to bottom of soil and positive to aerola3 

 of leaf induced rapid growth in the lowest cluster of fruit 

 but not in those above it. Side growths such as were 

 observed in the potatoes of the last experiment appeared 

 upon the stem, and the tomatoes ripened and turned red 

 before they had attained any size. Plants in other pots, 

 in which pieces of arc carbon had been placed just below 

 the surface of the soil not only made good progress but were 

 vigorous and healthy and fruited well. As, however, 

 there were no controls the experiments possess little value. 



Winter-Cherry Plants. 



These were interesting. There were two plants, identical 

 in size and condition. One was left untouched as a control 

 and the other electrified by means of a cell of 1 volt, positive 

 to soil and negative to aerolae of a leaf ; contact with the 

 latter being made with a steel needle joined to flexible 

 insulated wire. 



That the stimulated plant made better progress than the 

 control there could be no manner of doubt, but it soon 

 became evident that 1 volt was too much for it, because 

 the flowers displayed a tendency to fall off, and I came to 

 the conclusion that the flowering process should not be 

 unduly hurried and disconnected the cell for forty-eight 

 hours. This, however, was followed by a slackening of 

 growth and upon repeating alternate connection and dis- 

 connection noticed that the rate of growth varied accordingly, 

 that is to say, it decreased with disconnection and increased 

 when the current was again applied, but not at once : there 

 was always an interval of inertia. After a total of ten days 

 electrification the plant had four berries and twenty-three 

 flowers as against the three berries and eight flowers of the 



