PLANT DISEASES AND FUNGI.
27
The remaining six seeds, when removed from the soil, were decayed
and noisome.
In another experiment, eight seeds were placed on blotting
paper, moistened with distilled water, and covered. A duplicate set
were similarly watered with a solution containing bacteria from a
decaying cucumber. The first series all germinated with their usual
vigour, while those which came in contact with the bacterial germs
failed to germinate, and soon decayed.
"The pure virus was next introduced into the growing stems and
green fruits of the tomato, and in both cases quickly produced a
decay that caused the stems to fall, and the fruit to become a watery
mass enclosed by the skin, similar to the cucumber from which the
bacteria were taken for inoculation. At the time of the experiments
some boxes of young tomato plants were close at hand, and into the
centre of one of these a decaying cucumber was placed. In six hours
some of the stems of the tomato plant, six inches in height, had
rotted off close to the ground, where the liquid from the decaying
fruit had come in contact with the young plants. In ten hours all
the plants in the vicinity of the decaying cucumber were destroyed."
This account seems to be rather conclusive, especially when inde-
pendently and collaterally supported by evidence given by other
observers in respect to other plants, having similar results. From
the report of the New York Agricultural Station for 1887, we gather
that bacteria are found in great abundance in actively blighting
tissues of "pear blight," so as to be easily demonstrable to the naked
eye, and occur in less abundance in proportion as the disease is less
active. This disease may be introduced into healthy tissue by
inoculation with germs from diseased tissue. It is communicated
with equal certainty when the germs are separated from all accom-
panying juices of the diseased tissue, by a series of fractional cul-
tures. It is not communicated by the juices of the disease after the
germs are removed by filtration.
Without following this part of our subject further, it is essential
that we indicate some mode of escape or amelioration of this class of
plant diseases. It should be unnecessary to insist upon some similar
line of action to that pursued in similar diseases in man or animals.
In the first place there must be a scientifically accurate diagnosis of
the disease, and this must be followed by the special remedy which
has been proved effectual in that class of disease. There is no specific
for plant disease, as there is none for animal disease. We can point