fibers. Recent observations have established a great law in reference to the development of nerves, viz., the sensory fibers arise outside and grow into the central nervous system, motor fibers start within the central nervous system and grow outward. This applies even to the highest developed sensory nerves. For example, the fibers of the optic nerve begin in the retina of the eye and grow toward the brain, instead of starting in the brain and growing outward to the eye. Besides sensory and motor fibers there are those that regulate the nutrition and the tone of organs, called trophic nerves; those that carry impulses which stimulate secretion, called secretory nerves; and some others. The twelve pairs of cranial nerves are as follows: The first pair connected with smell; the second pair with sight; the third, fourth and sixth pairs with muscles that move the eyeball; the fifth pair with the teeth, tongue and face; the seventh pair the muscles of the face, the eighth pair the ears; the ninth pair the tongue, as nerves of taste, and with the muscles of the pharynx. The tenth pair (pneumogastric) are very important and widely distributed, going to the heart, lungs, stomach and intestines. The eleventh pair supply certain muscles in the neck; and the twelfth pair form the muscles of the tongue. Besides all these, there are nerves belonging to the sympathetic nervous system. The object of nerves is to connect the different parts of the body with the controlling nervous system. They are simply conductors and not originators of nervous impulses.
Nesting-Boxes. Birds may be attracted
about the home by putting up nesting-boxes.
If new material can not be had, use waste
or worn materials, for birds apparently prefer
rusty metal or weather-beaten lumber.
When I was a boy, I once secured four
HOLLOW-LIMB BOX
old shingles and a piece of board, made a
rough box with hatchet and saw, and put it up
in a tree. Many a pair of bluebirds nested
there. Such a shingle-box may be put against
the side of a building or on a tall pole or
tree-trunk where cats can not easily climb.
Better nail a shingle or some thin board
flat on the top, and have it project on
every side. If the board projects well out
over the entrance, it will prevent the rain
BARK BOX
from driving in as well as make the roof
rainproof. When hollow limbs are pruned from a
tree, cut them into sections, and roof, bore and
mount them. (See first illustration.) A
handsome as well as durable box may be made
of bark. It must be made late in June, when
the bark peels readily. It is made by peeling
off both the outer and the inner bark. Then
saw a slice off each end of the stick for the
bottom and the top, tack the bark on the
BLUEBIRDS' BOX
ends, nail on the supporting stick, and finally,
in order to make the top watertight, cover it
with green bark. (See second cut.) These
small boxes are suitable for the chickadee.
Chestnut-bark makes strong boxes, that can
be covered or roofed with zinc, for larger
birds. An objection to many bird-houses
is that they are not cat-proof. But a very
deep box, without a perch, but with an
overhanging cover or roof and with the
entrance well up under the eaves, makes
access difficult for the cat. The ordinary
bird-house for martins or tree-swallows
must stand on a tall, slim pole, these birds
preferring to be 15 to 30 feet above the
SLIDING-COVER BOX
ground. Be sure not to make the entrance
near the floor. Make a platform round the
box, and rail the platform up at least three
inches. Regulate the size and shape of
bird-boxes by the shape and habits of the
different birds. It is better to make them
comfortably large than too small. The size
of the entrance is most important. One
and seven-eighths inches diameter will do
for wrens; one and one-fourth for martins;
three and one-half for flickers and screech-owls.
Both bluebirds and tree-swallows have
been known to nest in boxes hung from a
wire. Provide every small nesting-box with
a sliding cover, or a door, through which
you can remove the contents. All the
boxes I have mentioned, except shingle and
bark boxes, provide for this, and these too
