THE EFFECT OF ELECTFJCITY UPON PLANTS. 
197 
to chemical changes occuring upon electrification. Their investigations 
seem to show that the immunity of a plant to disease depends mainly 
upon the nature of the chemical substances in the cell sap in the tissues 
exposed to infection. This view of immunity is also supported by 
recent work upon the biologic forms of parasitic fungi found in the 
Uredinese ^ and Erysiphaceie.^ 
In the bleaching of flour by means of the brush discharge, a toxic 
action of the discharge upon the micro-organisms present has been 
noted, but if this were operative in the case of the cucumbers one 
would have expected the disease to have appeared later, or not at all, 
in the electrified houses, whereas it appeared simultaneously in all the 
cucumber houses. I find it difficult to believe that when once present 
the bacteria within the leaf suffer more from the direct action of the 
current than the leaf itself. 
During the whole period of the Bitton experiments Mr. Newman 
states that, apart from the difficulties with the influence machine and 
oil engine, the electrical installation gave very little trouble, and only 
required attention in keeping the wires clear of cobwebs, stray shoots, &c. 
A somewhat similar installation was working during 
Gloucester, the same year over a vegetable garden in Gloucester, 
Here a somewhat higher voltage was given by the in- 
fluence machine, and the discharging points were kept five feet above 
the ground instead of sixteen inches above the tops of the plants as at 
Bitton. With the crops under electrification,- — 
Beet showed 33 per cent, increase ; 
Carrots showed 50 per cent, increase ; and 
Turnips showed an increase — not determined quantitatively, 
because of ihe destructive ravages of slugs on both crops. 
The amount of sugar in the beets was determined at the College. 
The unelectrified yielded 7*7 per cent, total sugar. 
The electrified ,, 8-8 per cent. ,, ,, 
Considering the total increase in the root crop this suggests that this 
method of electrification may find a valuable field of application in the 
cultivation of the sugar beet.^ 
The results of some small trials with wheat that were made at 
Gloucester were very favourable, and arrangements were made by 
Mr. Newman to try the effect of the overhead discharge system upon 
wheat and barley on a larger scale. 
Thanks to the interest taken in the work by Mr. R. 
Evesham. Bomford, of Bevington Hall, near Evesham, Mr. Newman 
was enabled to use some forty acres of this estate for 
experimental work in 1906, and experiments commenced on this ground 
in the Spring of that year, and are still being continued. 
^ Marshall Ward. Effect of Mineral Starvation on Parasitism of a Uredine 
Fungus. Procs. Royal Society. VoL 71. 1902. 
'^Salmon. Cultural Experiments with Biologic Forms of the Erysiphacese. 
Phil. Trans, of Royal Society. 197 B. 
^Lemstrom. Loc. cit., p. 47 and p. 55. 
