utton
that the young chickens of the parent stock, the Gallus bankiva, when
reared in India under a hen, are at first excessively wild. So it is
with young pheasants reared in England under a hen. It is not that
chickens have lost all fear, but fear only of dogs and cats, for if
the hen gives the danger chuckle they will run (more especially young
turkeys) from under her and conceal themselves in the surrounding grass
or thickets; and this is evidently done for the instinctive purpose of
allowing, as we see in wild ground-birds, their mother to fly away.
But this instinct retained by our chickens has become useless under
domestication, for the mother-hen has almost lost by disuse the power of
flight.

Hence, we may conclude that under domestication instincts have been
acquired and natural instincts have been lost, partly by habit and
partly by man selecting and accumulating, during successive generations,
peculiar mental habits and actions, which at first appeared from what we
must in our ignorance call an accident. In some cases compulsory habit
alone has sufficed to produce inherited mental changes; in other cases
compulsory habit has done nothing, and all has been the result of
selection, pursued both methodically and unconsciously; but in most
cases habit and selection have probably concurred.

SPECIAL INSTINCTS.

We shall, perhaps, best understand how instincts in a state of nature
have become modified by selection by considering a few cases. I will
select only three, namely, the instinct which leads the cuckoo to lay
her eggs in other birds' nests; the slave-making instinct of certain
ants; and the cell-making power of the hive-bee: these two latter
instincts have generally and justly been ranked by naturalists as the
most wonderful of all known instincts.

INSTINCTS OF THE CUCKOO.

It is supposed by some naturalists that the more immediate cause of
the instinct of the cuckoo is that she lays her eggs, not daily, but
at intervals of two or three days; so that, if she were to make her own
nest and sit on her own eggs, those first laid would have to be left
for some time unincubated or there would be eggs and young birds of
different ages in the same nest. If this were the case the process of
laying and hatching might be inconveniently long, more especially as
she migrates at a very early period; and the first hatched young would
probably have to be fed by the male alone. But the American cuckoo is
in this pr