86 THE ARGENTINE A^T. 
of the same room and " rediscovered " by the workers they seemed not 
to recognize its dangerous nature and would take it as before. After 
a few experiences of this kind the colony would move away from the 
vicinity. Only in rare instances were these migrations actually wit- 
nessed, as they seemed usually to take place during the night. A 
solution containing more than one-fourth of 1 per cent of arsenic did 
not give as good results for, in such cases, many of the workers died 
while sipping up the poison or on their way to the colony. Thus the 
poisonous nature of the substance was more quickly detected by the 
ants and work on it was stopped proportionately sooner. In all cases 
the ants removed the dead and dying from along their trails and from 
the vicinity of the poisoned mixture. 
A number of experiments were made to determine whether or not 
the ants could distinguish between poisoned and nonpoisoned foods, 
with the result that they evidently could not do so; this perhaps being 
the reason that they moved their colonies away from the vicinity. 
One of these experiments was as follows : 
On July 9 a fruit jar containing honey was placed on the floor of a 
small shed, where the ants had been very abundant for weeks. By 
the following day all honey had been removed by the workers and more 
was placed in the jar. Between the 9th and the 12th the jar was 
replenished several times, the ants during this time carrying away 
more than a half pint of honey. At noon on July 12 a small glass 
vessel containing a mixture composed of one-half of 1 per cent of 
arsenic and 20 per cent of sugar was placed about 3 inches from the 
hone}^ jar. The ants commenced taking this solution at once, and 
in the course of five minutes the vessel was black with them. At 4 
p. m. on the same day they were still working with undiminished 
vigor on both the honey and the poisoned solution. At 8 a. m. on 
July 13 there were only about one-fourth as many ants visiting the 
jars as on the previous day. They were still working on both the 
honey and the solution and many dead ants lay about. At noon of 
the same da}" very few were visiting the vessels, but many were 
engaged in carrying away the dead bodies of their erstwhile sisters. 
A few were still taking the arsenic solution, but it was evident that the 
ants did not know which of the food supplies was destroying them. 
At 2 p. m. on July 14 only two workers were in the vicinity of the ves- 
sels and neither of these was feeding. On July 15 all ants, both alive 
and dead, were gone, and not a single worker could be found in the 
building. Plenty of the nonpoisoned honey still remained in the jar. 
On July 16 and 17, also, no ants were to be found in the shed, even 
though heavy rainstorms in the meantime drove them indoors in 
many other buildings and decreased their available outdoor food sup- 
ply. This experiment and many others demonstrated not only the 
effect of the poison in driving the ants from the vicinity, but also that 
