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 gm 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 

 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. 



