of them is decidedly in the way of the other. At such a period, which
is almost a diplomatic crisis, great excitement is observed in the two
camps; there is a continual coming and going. One fine day, as the
result of some unknown act,--some mysterious _casus belli_ or
declaration of war,--two armies place themselves on the march against
each other. They advance in serried ranks. All ants do not follow the
same tactics; some throw themselves out in a thicker line, while
others form in squares. But as soon as action commences the individual
regains his rights. It is a series of duels, of fierce hand-to-hand
struggles. Legs are torn away, heads are cut off by strokes of the
jaws, abdomens are disembowelled; a terrible fury animates the
combatants, and nothing will disturb them from the battle. (Fig. 8.)
By-and-by victory remains with the fiercest or the strongest; the
vanquished draw in, carrying away as far as possible their wounded and
their dead. Nothing more is seen on the field of carnage but separated
limbs or heads which strew the ground like a multitude of small black
points. Often the enmity is not extinguished after a battle, and
several defeats are necessary before the weaker swarm is destroyed or
forced to emigrate.[36]

[36] P. Huber, _Moeurs des Fourmis indigenes_, chap. ix.
Many of the chief observations--given in the words of the
original observers--as well as a summary of the facts known
regarding the social activities of ants generally, will be
found in the useful volume by Romanes in the International
Scientific Series, _Animal Intelligence_, 1882.

CHAPTER III.

METHODS OF DEFENCE.

FLIGHT--FEINT--RESISTANCE IN COMMON BY SOCIAL
ANIMALS--SENTINELS.

Studying the animal kingdom in the manner here adopted, that is to say
by passing in review the various manifestations of zoological life, we
are necessarily led to find certain industries which are opposed to
others. We have seen the various methods of hunting; but attack calls
forth defence. In the struggle for life we find the action of beings
on other beings, and the re-action of these latter; the final result
is the expression of the difference between the two according as one
or the other is stronger.

_Flight._--Just as the most rudimentary method of attack is simple
pursuit, so the most simple and natural method of defence is flight;
but if very fleet animals like hares, gazelles, a