26 BULLETIN 965, U. S. DEPARTMENT OF AGRICULTURE. 
being dissolved in lukewarm water, to which the dissolved arsenic and 
honey were then added. No tartaric acid was used, for an alkaline 
sirup, which might prove more attractive to ants, was desired. 
During the first week the ants fed more freely on the unboiled sirup 
than on the boiled sirup in an adjacent plot, and at the end of the 
first month both sirups proved equally attractive. The unboiled 
sirup then started to turn dark and decompose, after which its 
attractiveness to ants was greatly decreased. The boiled sirup, how- 
ever, was in perfect condition at the end of the month and its attrac- 
tiveness continued. This plainly shows that the unst ability of an 
unboiled sirup renders it less useful than the boiled sirup. 
Saccharin.— The shortage of sugar in 1918 led to experiments with 
substitutes, and of these saccharin, supposedly 600 times sweeter than 
sugar, was one of the first tried. A formula was prepared using 
three-fourths of an ounce of saccharin, 2 pounds of honey, and three- 
fourths of an ounce of sodium arsenite to 2 gallons of water. Three- 
fourths of an ounce of saccharin is equivalent to 28 pounds of sugar, 
and at this rate the sweetness of the sirup was approximately twice 
that of the regular Barber formula. This sirup was lightly attended 
by ants during the first few days following its distribution, but there- 
after proved repellent. Other formulas were made containing de- 
creased amounts of saccharin, but in all cases the sirup proved 
unattractive to the ants. 
Glucose. — Glucose was used in several different formulas as a sub- 
stitute for sugar. In no case did it prove as attractive or effective 
as the original or modified Barber formulas. 
MODIFIED BARBER FORMULA AND CHLORAL HYDRATE. 
A sugar sirup with chloral hydrate as the poison proved highly 
attractive to ants but did not possess the required killing properties. 
It was thought, therefore, that chloral hydrate added to the modified 
arsenical formula might increase the attractiveness of the latter to 
ants and result in their very rapid eradication. Accordingly, 3 
ounces of chloral hydrate in solution was added to 1 gallon of the 
arsenical sirup and the mixture distributed in containers on ant- 
infested trees. The ants attended the cans slightly at first, but the 
sirup proved repellent. Other formulas with greatly reduced chloral 
hydrate proved equally repellent. 
FINAL FORMULA. 
The thickening of the sirup in modified FormulaT during the sum- 
mer and its frequent crystallization after protracted exposure to cold 
weather during the winter led to the preparation of a still more dilute 
ant sirup, in which 11 pints of water were used instead of 8 pints as 
previously. This new sirup was first prepared during the spring of 
