64 BULLETIN" 647, U. S. DEPARTMENT OF AGRICULTURE. 
It seemed desirable to give this chemical a thorough trial in the 
field, but it was necessary to devise a means of protecting the mer- 
curic salt from rain. The ant tapes and liquids on the market were 
useless for outdoor work, because their value was quickly destroyed 
by moisture. 
In original experiments performed by the writer it was found 
that the corrosive sublimate could be made impervious to water by 
dissolving this salt in an alcoholic solution of shellac. A consider- 
able experimentation, in which both methyl and ethyl alcohol and 
various strengths of the mercury were used, resulted in the following 
formula, which was most satisfactory : 
Corrosive sublimate gra__ 20 
Ethyl alcohol c. c__ 60 
Shellac gm__ 31 
The corrosive sublimate is first dissolved in the alcohol, then the 
shellac added, and the mixture shaken until all is dissolved. 
In the few tests made with this mixture in the field it proved 
effective against the ants for about two months under the most 
trying conditions. It is less effective, however, than the adhesive 
mixture previously described, and too expensive for use on a large 
scale. It must never be applied directly to trees, as it will quickly 
kill the bark clear through and ultimately destroy the tree. It may 
be used by first applying thickly to strips of cloth, or soaking the 
latter in the solution, and then allowing them to dry out thoroughly. 
This method is, however, too tedious and expensive for practical use. 
Shellac solution of corrosive sublimate, made after the foregoing 
formula and painted in bands from 6 to 8 inches wide on the legs of 
tables, refrigerators, etc., where food is kept, ordinarily will keep 
che ants away for a year or more. The banding material will not 
long retain its strength when applied to metal surfaces, such as 
stove legs and galvanized-iron garbage pails. 
There is considerable danger attendant upon the careless use of 
corrosive sublimate, but if the precaution is taken not to get it into 
a cut or abrasion, or into the mouth or eyes while mixing, there is 
nothing to fear from it. It is much safer to handle in the form of a 
shellac solution than in that of an ant tape, being applied with a 
paint brush and not requiring any direct handling whatever. Once 
the " paint " has become dry there is no chance for the corrosive 
sublimate to shake loose and get into food. In making ant tape, 
on the contrary, there is danger of splashing the solution into the 
face or of getting it into a slight cut on the hands in soaking and 4 
drying the cloth strips, and when these are applied the loose poison 
in the fibers of the cloth is a constant source of danger to young 
children and domestic pets. 
