362 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
The chlorpicrin available for the earlier experiments contained a 
small amount of chlorine and nitrogen peroxide. With this material 
a slight bleaching of No. 1 and No. 7 was noted. When chemically 
pure chlorpicrin was used at the rate of two pounds per 1,000 cubic feet 
no bleaching was observed. Chlorpicrin may, therefore, be used to 
fumigate clothing, providing it does not contain impurities of chlo¬ 
rine and nitrogen peroxide. Even with the impurities the bleaching 
was not so great as would result from the washing of either of these 
materials. 
Conclusion 
Chlorpicrin cannot, at the present time, be obtained on the market, 
but the writer has been assured, through correspondence with chemical 
firms, that after the war it will be possible to manufacture this chemical 
for about thirty cents a pound in large quantities. Even if retailing 
for from seventy-five cents to one dollar a pound it would be a cheaper 
fumigant than carbon bisulphide. These results are published in 
order that others may try out this interesting compound. Chlorpicrin 
is a very poisonous compound, hence care should be exercised 
in its use. Owing to its irritation to the eyes and nasal passages it 
could never be used on a large scale or where it would be difficult to 
remove the vapor after the fumigation. It may prove of value in the 
fumigation of small quantities of grain or seeds, samples of grain such 
as the agronomist wishes to preserve, for the destruction of ant nests or 
gophers, while light doses may prove of value for the destruction of 
mosquitoes in yellow fever regions. 
The following points summarize the experiments: 
1. Chlorpicrin used at the rate of from one-half pound to one pound 
to 1,000 cubic feet will destroy insects, which require from three to 
eight pounds of carbon bisulphide. 
2. There is more likelihood of injury to germination than in the use 
of carbon bisulphide, but with normal doses, if the grain is dry and is 
thoroughly aired after fumigation, no injury results. 
3. Chlorpicrin is able to penetrate through fifty pound sacks of 
flour in twenty-four hours at a temperature of 70° killing all the 
insects. 
4. Chlorpicrin has a slight injurious influence on the baking quali¬ 
ties of flour. 
5. Chlorpicrin free from impurities of chlorine and nitrogen peroxide 
will injure neither dress materials nor their color. 
