of
two among them. The two sanguineae are so touched by this gesture, which
turns their instinct topsy-turvy, that they disgorge their honeyed store
and feed the young enemy. Thenceforward all is well. An offensive and
defensive alliance is formed between the little pratensis and the
sanguineae against the ants of the young one's own species. The alliance
becomes irrevocable.

Let me adduce another example; the results of a common danger. Forel
places in a bag a nest of sanguineae and another of pratenses. He shakes
them together, and leaves them in the bag for an hour. Thereafter he
opens the bag and places it in direct contact with an artificial nest.
At first we witness a general state of confusion, a delirium of fear.
The ants cannot recognise one another apart; they show their mandibles,
and then sidle away in a panic. But by degrees calm is restored. The
sanguineae begin by removing the pupae, taking indifferently those of
both species. Some of the pratenses follow their example. From time to
time fights take place, but these are merely single combats, and they
grow less and less fierce. From the next day onwards, all work
together. In four days the pact is sealed; the pratenses disgorge food
to the sanguineae. At the end of a week, Forel transports them to the
neighbourhood of an abandoned ant-hill. They settle in, helping one
another in the house-moving, carrying one another, and so forth. No more
than a few isolated individuals of the respective species,
irreconcilable nationalists no doubt, keep up their sacred enmity, and
end by killing one another. A fortnight later, the mixed community is
flourishing; perfect concord prevails. The summit of the ant-hill, which
at ordinary times is covered with pratenses for the most part, reddens
with the martial sanguineae directly danger threatens the common state.
Next month, Forel, carrying the experiment a stage further, went to the
old nest for a number of the pratenses and put them down just outside
the hill of the mixed community. The newcomers promptly fell upon the
sanguineae. But these latter defended themselves without animosity,
merely knocking the aggressors head over heels, and then letting them
alone. The pratenses could not make it out. As for the other pratenses,
those belonging to the mixed community, they avoided their sometime
sisters, would not fight with them, but carried the pupae into the nest.
The hostility was all on the side of the newcomers. Ne