This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
In a late number of the New York Herald, we find an article from Mr. John F. Bennett, Pittsburgh, Pa., upon the rot in grapes. Mr. Bennett we know to be a close observer, and to have traveled widely, ever having his eyes and ears open. In this art-cle, he takes the ground that grape-rot is the result of blows, local, and produced by lightning. After rehearsing the various soils and the elemepts of growth - heat, light, water, etc. - and the various supposed causes of the disease, he goes on to say that "It is not caused from within by disease of the plant in roots or branches, otherwise all the branches and berries would be affected and not (as is the case) individual berries on some of the branches. Then it is caused by some external influence; and if external it must be mechanical - an effect.
In its manner of action it is shown to be local; a blow or wound received, more or less minute, causing death to the part receiving it, and spreading its decomposition into the parts surrounding. What is there in nature gives blows causing death? Lightning does. Lightning is an effect, and therefore mechanical. It is prevalent in summer and not in winter. It always takes place during close, damp, sultry weather, which it clears in showers of rain."
He then explains the manner in which lightning gives this deadly stroke which is the burning thereby of oxygen and hydrogen, producing steam which, in even minute particles, is destructive of life. He says:
"If the point struck is so minutely struck as to bear a small relative proportion to the whole of the living object, the part struck and become dead is ejected from the living body, leaving a scar or wound; if it bears so large a proportion that the remaining living part of the body canuot recover, the decay extends, and, in a longer or shorter time, the whole body perishes. If the body struck, by reason of the free and nascent elements within it, is capable of being ignited, and so continues the flash through its whole body, instant death in all its parts takes place. In all cases where vivid flashes of lightning occur, the influence extends a considerable distance around; and although the flash may appear to kill only where it strikes, it yet ignites the suitable free elements around it, and kills in part, or so as to injure more or less severely, all around. Also, where there is no vivid lightning or flash during the moist sultry weather, the same processes are taking place, minutely wounding every vegetable and animal life - in vegetables showing itself by small scars on the leaves, and in animals by a tendency to diarrhaea. During this hot wet weather, the earth become-a bad conductor away of these free elements, and the more so when from the nature of the soil water is retained.
Thus, the plants growing on clayey, marly soils are more subject to the attacks of this silent lightning or electricity than those growing on porous, sandy soils.