8 
This point has been discussed rather fully, not because there is any 
particular danger or need for fear in handling this insecticide, but in 
order to lessen the fear of its use and to neutralize whatever danger 
there may be in its application by giving an intelligent understanding 
of the precise nature and effects of the chemical. When these are 
known, it can be handled with much greater safety and far less fear 
than is possible where the user knows there is danger, but does not 
know just what the danger is. The danger from its use is practically 
of the same kind as that from gasoline, which is in common use in 
thousands of homes. Really, the danger is very much less, since every 
precaution is taken to keep carbon bisulphid from the proximity of 
fire, while gasoline is used principally in connection with fire. 
CARBON BISULPHID AS AN INSECTICIDE. 
FIRST USE AS AN INSECTICIDE. 
So far as the writer can learn, the first use of carbon bisulphid as an 
insecticide was made in 1856 and 1857 by M. Doyere, who demon- 
strated 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 increased,.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 dif- 
ferent 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 poisoning 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, there- 
fore, be closely confined in order to maintain a sufficient proportion 
