In June 1869, very soon after the formation of my
garden, the leaf-cutting ants came down upon it, and
at once commenced denuding the young bananas, orange,
and mango trees of their leaves. I followed up
the paths of the invading hosts to their nest, which
was about one hundred yards distant, close to the edge
of the forest. The nest was not a very large
one, the low mound of earth covering it being about
four yards in diameter. At first I tried to stop
the holes up, but fresh ones were immediately opened
out: I then dug down below the mound, and laid
bare the chambers beneath, filled with ant-food and
young ants in every stage of growth; but I soon found
that the underground ramifications extended so far,
and to so great a depth, while the ants were continually
at work making fresh excavations, that it would be
an immense task to eradicate them by such means; and
notwithstanding all the digging I had done the first
day, I found them the next as busily at work as ever
at my garden, which they were rapidly defoliating.
At this stage, our medical officer, Dr.
J.H.
Simpson,* came to my assistance, and suggested pouring
carbolic acid, mixed with water, down their burrows.
(* This gentleman, beloved by all who knew him, of
rare talent, and with every prospect of a prosperous
career before him, died at Jamaica from hydrophobia,
between two and three months after being bitten by
a small dog that had not itself shown any symptoms
of that disease.) The suggestion proved a most valuable
one. We had a quantity of common brown carbolic
acid, about a pint of which I mixed with four buckets
of water, and, after stirring it well about, poured
it down the burrows; I could hear it rumbling down
to the lowest depths of the formicarium four or five
feet from the surface. The effect was all I could
have wished: the marauding parties were at once
drawn off from my garden to meet the new danger at
home. The whole formicarium was disorganised.
Big fellows came stalking up from the cavernous regions
below, only to descend again in the utmost perplexity.
Next day I found them busily employed bringing up
the ant-food from the old burrows, and carrying it
to a new one a few yards distant; and here I first
noticed a wonderful instance of their reasoning powers.
Between the old burrows and the new one was a steep
slope. Instead of descending this with their
burdens, they cast them down on the top of the slope,
whence they rolled down to the bottom, where another
relay of labourers picked them up and carried them
to the new burrow. It was amusing to watch the
ants hurrying out with bundles of food, dropping them
over the slope, and rushing back immediately for more.
They also brought out great numbers of dead ants that
the fumes of the carbolic acid had killed. A few
days afterwards, when I visited the locality again,
I found both the old burrows and the new one entirely
deserted, and I thought they had died off; but subsequent
events convinced me that the survivors had only moved
away to a greater distance.
