202 
THE EFFECT OF ELECTRICITY UPON PLANTS. 
As the result of further experiment, however, it has never been 
possible to demonstrate starch in an electrified leaf, if that leaf were 
quite free from starch at the commencement of the experiment. The 
presence of the starch in the earlier experiments seems to have been 
due to the inhibition of the normal transformation of starch into sugar^ 
owing to the excessive strength of current used. 
The experiments were made with Elodea, with Geranium and Coleus 
leaves, and also with green filamentous Algfe, such as Spirogya and 
Cladophora laid across platinum electrodes; the voltage used varied 
from 1 to 40 volts, above 40 the effect was usually fatal. 
With the object of ascertaining whether starch were produced by 
the action of the silent discharge in the dark, Mr. ISTewman kindly kept 
plants beneath the discharge points at Bitton during a continuous run 
of 27 hours, the leaves being afterwards picked and examined. No- 
starch was found in them. 
I find myself then, at present, unable to accept Pollacci’s conclusion 
that starch can be formed by a green plant in the dark if an electric 
current of suitable strength be passed through it. 
It has also been suggested that the effect produced on the soil by 
the electric current may be beneficial to the plant. Electrolysis, 
undoubtedly takes place, and Dr. Cook found the soil slightly acid 
near the anode, and alkaline near the kathode, in some of his- 
experiments. 
Ewart 1 suggests that the current increases the rate of solution and 
absorption of the insoluble food constituents present in the soil, but 
as the amount of electrolysis proceeding is not likely to make the soil 
locally very acid I do not see that this is likely to be the case. 
Finally, there is the possibility that in the case of the overhead dis- 
charge, oxides of nitrogen are formed by oxidation of either the nitrogen 
or ammonia present in the air. 
Samples of the soil from the electrified and unelectrified parts of the 
wheat field in the Evesham experiments were analysed at College, the 
samples having been taken in the autumn after both crops had been 
gathered. They showed, — 
Electrified ... ... 0T59 per cent, on dry weight. 
Unelectrified ... ... 0'056 per cent, on dry weight. 
But it is impossible to draw conclusions from isolated analyses of 
this kind ; however, following up this suggestion, it is intended to keep 
a continuous check upon the soils by analysis during the present season. 
Berthelot considers that the clue to advantage of the electric dis- 
charge is to be found in an entrance of atmospheric nitrogen into the 
plant metabolism, but suggests that this is due not only to the forma- 
tion of oxide of nitrogen, but also to the combination of gaseous nitrogen 
with carbohydrates within the plant. 
^ Ewart. Protoplasmic Streaming. P. 99. 
- Berthelot. Sur les conditions de mise en activite chimique de I’eletricite- 
silencieuse. Cornptes Rendus. Vol. 131, p. 772. 1900. 
