78 
i Abstracts from Farmer's Bulletin No. 145. Pages 78 to 1)5 inclusive. > 
CARBON BISULPHID AS AN INSECTICIDE. 
FIRST USE AS AN INSECTICIDE. 
So far as the writer can learn, the use of carbon bisulphid 
as an insecticide was made in 1856 and 1857 by M. Doyere, who 
demonstrated that a small amount of the liquid poured into a 
pit of corn or barley would kill all the weevils and their eggs; 
that this chemical agent did not alter at all the quality of the 
grain; that it left only a slight odor, which was not, however, 
persistent, but disappeared promptly upon the exposure of the 
grain to the free air. Since that time its use has steadily in- 
creased and it is now generally recognized as one of the most 
useful insecticides. 
APPLICABILITY TO VARIOUS INSECTS. 
Carbon bisulphid is applicable to a large number of insect 
pests living under very different conditions, which, therefore, 
require different modes of application. These insects can be 
divided into groups, according to certain similarities of their 
habits of life or of their habitats. The members of each group 
have been found to be susceptible to practically the same mode 
of treatment with such minor variations as the individual life 
histories may require for greatest effectiveness. In a general 
way we may say that carbon bisulphid is applicable only where 
its vapor can be more or less confined. Its field of usefulness 
is among those insects which can not be reached through poison- 
ing their food and those that are very difficult to reach with 
contact insecticides by spraying. Such insects are found both 
indoors and out of doors, and the general methods of treatment 
in these two environments must necessarily vary considerably. 
DIFFUSION OF THE VAPOR. 
This vapor diffuses through the air very rapidly and must, 
therefore, be closely confined in order to maintain a sufficient 
proportion of it in the atmosphere to prove fatal to insect life.' 
It tends most strongly to spread outward and downward on 
account of its being so heavy, and, though it will gradually work 
upward, its greatest density will be at the lowest levels. . The 
usual calculation is to employ one pound of liquid carbon 'bisul- 
phid to each 1,000 cubic feet of space treated, whether for the 
treatment of insects in buildings or for Insects in the ground. 
This amount gives an atmosphere, if confined to that space, 
composed . approximately of 1 part in 90 of carbon bisulphid 
vapor, which, as we shall see, is a fatal strength in a short 
time. However, where the atmosphere cannot be absolutely 
confined and there is considerable opportunity for the vapor 
to escape, it is frequently necessary to apply from two to four 
times that amount, under circumstances where there is no 
danger of killing plant life. 
INSECTICIDAL POWER. 
In 1876 two French investigators, Cornu and Mouillefert, 
performed a series of experiments to determine the insecticidal 
power of carbon bisulphid vapor. They were working primarily 
upon the grape Phylloxera, but, in addition to that insect, they 
experimented with caterpillars, butterflies, cicadas, wasps and 
