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INCIDENTAL EFFECTS OF TREATMENT WITH CARBON BISULPHID. 
EFFECT OF THE VAPOR UPON PLANTS. 
In using carbon bisulphid against the grape phylloxera in France, 
it was soon learned that direct contact of the liquid with the roots 
will always prove fatal to the plant, but that roots will withstand a 
considerable amount of the vapor without injury. The difference 
between the minimum of vapor which will destroy the insects and the 
maximum amount which can be used without injury to the plant con- 
stitutes the range of usefulness of this insecticide. Extensive experi- 
ments were made by two French investigators. Their first experiments 
were made by treating two series of plants, the first with varying 
amounts of carbon bisulphid emulsified in water, the second with the 
same amounts without the water. The results showed that the water 
moderated the action of the liquid. Succeeding experiments confirmed 
this result and also showed that different plants possessed different 
powers of resistance to the insecticide. The moderating influence of the 
water was doubtless due to its having increased the humidity of the 
soil, which, as previously stated, would retard evaporation and dif- 
fusion. Of all the plants tried, the grape appeared the most resistant. 
Strong, vigorous vines will also resist heavier doses than will vines 
enfeebled by insects or disease. 
INFLUENCE UPON THE GROWTH OF CROPS. 
As a general rule, the crops grown upon soil treated with carbon 
bisulphid are very good. This fact suggests several questions: Is 
the vapor itself a vegetable excitant? Does it produce chemical decom- 
positions which render more assimilable certain nutritive elements 
already present in the soil? Has it some particular effect upon the 
humus? Or is its benefit wholly due to the destruction of the lower 
plant and animal organisms which, living in the soil upon the roots of the 
plants, steal nourishment therefrom and thus weaken the vitality of 
their host? None of these questions seems to have been satisfactorily 
answered. However, it is an acknowledged fact that the growth fol- 
lowing treatment is unusually good, and the few records which we 
find indicate that the increase is considerable. Treatment of a corn- 
field yielded an increase of 46.8 per cent in the grain and 21.73 per 
cent in the stover. Potatoes showed an increase in weight varying 
from 5.3 per cent to 38.7 per cent. Ina series of experiments upon 
corn, oats, beets, potatoes, and clover, much the same results were 
obtained, but, strange as it may seem, the most marked increase was in 
the clover. It was found that the vapor was not detrimental to the 
active bacteria causing the nodules upon the roots of this legume, but 
rather seemed to favor their multiplication. Furthermore, it was found 
upon these same plats that the beneficent influence of the treatment 
