THE ARGENTINE ANT: DISTRIBUTION AND CONTROL. -15 
greatly modified sirup. In all the experiments the sirup proved very 
attractive and palatable to the ants at first, but their visits gradually 
decreased until the sirup was avoided, although in some instances the 
trails continued to pass by the poison jars. The period of attendance 
at the sirup varied somewhat with the seasons, being longer in winter. 
Even in the winter, however, a repellent action was apparent. In 
preparing the solution it had been noticed that the sirup turned 
brown, becoming darker the longer it was boiled, although it was 
made in a pail which in turn was placed in a bath to prevent burning. 
Another objection was the crystallization of the sirup to a greater 
or less extent upon cooling. On the advice of a sugar chemist the 
proportion of water was increased to make a saturated sugar solu- 
tion ; 10 pounds of water to 20 pounds of sugar and 1 ounce of sodium 
arsenite were used. The Nickels sirup contained one-fourth per cent 
arsenic, while this more dilute sirup contained one-fifth per cent, 
but the dilute sirup was quite effective. With the exception of the 
first application, the dilute sirup was used throughout the length 
of the Hattiesburg experiment. Crystallization of from 5 to 15 
per cent of the weight of sirup still occurred in short periods, but 
as high as 50 per cent when the sirup had been in the jars for several 
months. This of course had the effect of proportionally increasing 
the percentage of poison in the liquid and consequently its repellent 
power. Newly made sirup appeared to be less repellent than that 
which had stood for several weeks. 
The repellent action of the sirup is illustrated by an experiment 
conducted in a private residence, which was badly overrun with ants. 
The ants were abundant in the refrigerator, safe, and sink, and literally 
covered the floors. Six fruit jars containing the Nickels sirup and 
sponges were placed in different rooms in the house, and 6 paraffined 
paper bags containing the same sirup and a sponge were placed 
around the house outdoors on trees, fence, and back porch. ‘The 
sirup was about a month old. The experiment was begun at 1 p. m. 
At 5 p.m. hardly an ant was to be seen in the house, although a few 
were to be found at each jar and many were visiting the bags. Two 
days later not an ant could be found in the house and only three of 
the bags were attended by ants. As it seemed impossible that the 
colonies could have been exterminated so quickly, the adjacent vacant | 
lot was inspected. This lot was overgrown with weeds, and in a 
corner near the house there was a pile of old lumber. Ants were 
found in abundance nesting in the lumber, and many were present 
wherever they could find dry quarters in the lot. It was quite evident 
that the ants had been repelled by the poison. 
A series of experiments to obtain definite data on the repellent 
properties of the sirup were conducted in the Horticultural Hall, 
