d has been developed
until the creatures display their unornamental tail feathers with all
the dignity with which a peacock shows his marvellous decorations. The
pouters have in some unaccountable way learned to take air into their
crop; and the habit has been developed by selection until the bird
destroys all trace of his original shapeliness, though he seems to take
pride in his diseased appearance. The tumbler, probably derived from
some ancestor afflicted with a disease of an epileptic character,
manages to go through his convulsions in the air without serious
consequences and apparently with some pleasure to himself. There are
over one hundred less conspicuous varieties, of which only one deserves
notice, and this for the reason that it has some possible utility to
man and is now much attended to. This is known as the carrier pigeon.

[Illustration: The Giant Crowned Pigeon of India]

In early time, before the invention of the railway and telegraph, some
ingenious breeder of pigeons, observing the constant way in which these
creatures returned to the place where they were bred, invented the plan
of using them to convey information. This service was found convenient
not only for ordinary correspondence, but was exceedingly valuable where
a place was beleaguered by an enemy. In such cases carrier pigeons could
often be used to convey information across the otherwise impassable
lines. Even in modern times, as, for instance, during the last siege of
Paris, these swift and sure flying birds proved of great use in keeping
up communications between the people of the invested town and the French
armies in the field. Letters in cipher, sometimes photographed down
until the characters were microscopically fine, were made into packages
of small weight in order not to impede the flight of the bird, carefully
affixed to its body, and thus sent away. Very generally these curious
shipments came to the hands of those for whom they were destined. The
birds can be trusted to fly at night; they retain for a long time the
memory of their home, and spare no pains to return to it.

The homing power of the carrier pigeon appears to be a special
development of a natural capacity, as is also its swiftness and
endurance in flight. Our other breeds and the wild species whence they
have all come are not disposed to undertake long journeys; they rarely,
indeed, wander far from their abiding places. Our experience with the
carriers shows how