200 
THE EFFECT OF ELECTRICITY UPON PLANTS. 
Another series of experiments with beans was started upon May 
25th, but in this case no difference in rate of germination was noted, 
while later the whole crop was so badly attacked by Aphis that further 
comparisons could not be made. 
The following table shows the results obtained with other plants by 
this method : — 
Wheat, no difference. 
Barley, Electrical, matured earlier. 
Maize, 
Cabbage, 
Radish, 
Carrot, 
Lettuce, 
the weaker plants, 
markedly better plants, 
ready for pulling earlier, 
larger, and with much more 
leaf development, 
better developed plants. 
The results are then inconclusive, though in most cases the plants 
where the current is passing have fared better. As an example of the 
strength of the currents used, with plates of area about 200 square 
inches, 4 feet apart, a current of 12 milli-amperes was passing, the soil 
being very damp. 
PHYSIOLOGICAL ACTION OF CURRENT. 
The chief aim in this paper has been to give an account of these 
large scale experiments with different methods, but it may be as well 
to give an <'iccount of some of the theories advanced to explain the 
physiological action of the current, and to describe the results of 
some further experimental work, though the results of the latter are 
negative in character. 
It is obvious that the practical application of any method of electri- 
fication can only be empirical until the physiological effect of the 
current upon the plant is understood. 
One suggestion, frequently made, is that the passage of water up the 
plant is aided by the electric current. Lemstrom advances this sugges- 
tion, and referred to experiments in which he had found that if a 
negatively charged wire is placed over a capillary tube which dips into 
water, the water climbs up the sides of the tube and collects in drops 
at a higher level. 
But if a positively charged pole is placed above the tube this did not 
happen, and with a positively charged overhead wire system he 
obtained the best results. 
J. Chundar Bose ^ explains the rise of sap on the assumption of a 
pumping action of the living cells throughout the course of the xylem ; 
the pumping action being a form of response to stimulus. 
If this theory is correct the current might be conceived as a stimulus 
giving rise to increased response, and therefore accelerating the flow 
of sap. 
^ J. C. Bose. Plant Response. Longmans, Green, & Co. 1906. 
