21 
EFFECT OF HYDROCYANIC-ACID GAS FUMIGATION ON SEED MATERIAL. 
As to the effect of hydrocyanic-acid gas on the germination of 
seeds, a series of tests was conducted by Dr. C. O. Townsend, now 
of this Department, when connected with the Maryland state horti- 
‘cultural department, with the resulting conclusion that dry grains 
and other seeds can be treated with hydrocyanic-acid gas for insect 
pests at the usual strength and time, or even for several days, without 
in any way poisoning the grain, from which it was deduced that in 
the ordinary process this method of fumigation can be employed 
without injuring seeds either for planting or as food. Damp grains 
and other seeds, however, are more susceptible to the influence of 
hydrocyanic-acid gas, and some precaution must be observed in such 
cases to avoid moisture. 
OTHER REMEDIES. 
While the object of the present circular is to furnish information 
for the fumigation of mills and other buildings by hydrocyanic-acid 
gas as a remedy for the flour moth, it would be unwise to omit stat- 
ing that there are several other good remedies, which, however, are 
not always possible of application. 
Bisulphid of carbon.—One of these is bisulphid of carbon, especially 
for small inclosures. It is claimed by some millers to be of value for 
a first fumigation, following with hydrocyanic-acid gas.t When 
forced into the spouts, machinery, and other portions of the mill, it 
is a factor in killing the moth and other insects. 
Cleanliness.—The maintenance of scrupulous cleanliness through- 
out the mill undoubtedly does much toward preventing the introduc- 
tion of the flour moth as well as in restraining its increase after it 
has once obtained a foothold in the mill. Directions for cleaning 
have been given on page 13. Prominent millers in some of our large 
cities, e. g., in Louisville, Ky., and in Kansas City, Mo., as elsewhere, 
have attributed immunity from the flour moth to the fact that they 
maintain the most rigid system of cleanliness in their mills. 
Sulphur was used somewhat extensively as a remedy for the flour 
moth several years before the general employment of hydrocyanic- 
acid gas, and it is still valuable and in constant use by millers in some 
States. Lack of space prevents further discussion of this method. 
Freezing is an inexpensive and valuable remedy where practicable. 
Where an infested mill can be left open to a temperature of zero or 
lower, three to ten nights of such exposure continuously or at inter- 
a Details in regard to the employment of bisulphid of carbon for fumigating build- 
ings are given in Farmers’ Bulletin No. 145, pp. 19-20. Other valuable information 
regarding this insecticide is also furnished. Copies may be obtained gratis on appli- 
cation to Members of Congress or to the Secretary of Agriculture. 
[Cir. 112] 
