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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
the cyanide radical were discarded for various reasons, the principal 
reason being the inability to build up and maintain a sufficiently high 
concentration in the field owing to their low density. When the 
Public Health Service in 1922 requested the assistance of the Chemical 
Warfare Service in finding either a compound which could be released 
with hydrocyanic acid to make the presence of hydrocyanic acid more 
noticeable or to develop a substitute for hydrocyanic acid in ship fumi¬ 
gation this data on cyanide compounds was made available to them. 
After some little experimental work it was found that although a 
lachrymator could be very readily released with hydrocyanic acid the 
lachrymator persisted after the cyanide had been cleared out of the 
ship’s hold. Work was then begun on a substitute for hydrocyanic acid. 
This substitute was to be as toxic to rodents and vermin as hydrocyanic 
acid; must either have a powerful odor or be a lachrymator so that its 
presence could be easily detected. It must also be readily generated in 
place in similar fashion to that used for generating hydrocyanic acid, 
i.e. by dropping a relatively inert cyanide compound into an acid where 
a more active cyanide gas was formed. The compound must also be 
very volatile and as readily cleared out of the ship’s hold as hydrocyanic 
acid. After considerable experimentation in conjunction with the 
Public Health Service cyanogen chloride, generated by dropping the 
desired amount of granulated sodium cyanide and sodium chlorate into 
dilute hydrochloric acid, was selected as possessing all the qualifications 
of hydrocyanic acid. Cyanogen chloride is almost as toxic to insects 
and vermin as is hydrocyanic acid and in addition is a vigorous lachrym¬ 
ator. It was found to be a very good germicide which is not true for 
hydrocyanic acid. Cyanogen chloride, generated in this manner, was 
tried out and proved effective in ridding various buildings at Edgewood 
Arsenal of rats, mice, bats, roaches and bedbugs. In addition work has 
been carried out by the Public Health Service against other sorts of 
vermin and germs, both in the laboratories and on board ship. This 
gas will soon be used by the Public Health Service on all ship fumigation 
carried on under that bureau. 
The Quartermaster of Washington Barracks requested the Chief of 
Chemical Warfare Service to try cyanogen to rid various buildings at 
Washington Barracks and the Army War College of roaches and ants 
which had increased to such a number, despite insect powders of all 
sorts, that they had reached the proportions of a plague. This report 
covers the fumigation of these buildings at Washington Barracks and the 
Army War College. The buildings included the Post Quartermaster’s 
