readily the creatures may be educated to perform
feats which they were not accustomed to do in their wild state.
Something of the same elasticity of constitution may be observed in the
bodies of our pigeons as they have been affected by selection. Not only
has the plumage been greatly altered by the breeder's art and in
pursuance of his plans, but the form and proportions of the bones have
coincidently and unintentionally been greatly changed. So considerable
are these alterations that if these creatures were submitted for
dissection to a naturalist who knew nothing of the history of the bird,
he would have no hesitation in classing them as belonging not only in
different species, but as members of diverse genera.

It must be regarded as unfortunate that the experiments which have been
made on pigeons have been limited to their features of form, color, and
slight peculiarities in their habits. If the breeders had sought to
modify the intellectual parts with anything like the insistence which
they have given to the development of these bodily peculiarities, we
might now have a most valuable store of knowledge as to the limitations
of animal minds. The facts gained in the breeding of the carriers show
clearly that certain of the instincts of these birds can be readily
modified. There is every reason to suppose that their mental capacities
in other directions have something of the same pliability.

[Illustration: The English Pheasant]

Although the pigeon is the only free-flying form which has been won to
intimate relations with man, there are numerous other species of these
volant creatures which have been reduced to partial domestication,
though they cannot be trusted to abide with us without being more or
less completely caged. Experience has shown that by far the greater part
of the arboreal birds may be kept and will breed in captivity. From the
host of these feathered creatures men have from time to time selected
species which grace their habitations by their beauty, their song, or by
the sympathetic relations which they form with their captors. Our
successes in these efforts toward domestication of these birds have been
most eminent with those varieties which in their wilderness state have a
well-developed social life, which abide in families or flocks, and have
the pairing habit well affirmed. The reason for this has been already
indicated. It is due to the sympathetic motive which is developed in
such communal l