The Abbeville press and banner. [volume] (Abbeville, S.C.) 1869-1924, 1880-05-05
HibernatiOn.

Most beasts do not hibernate, because
they have the power of keeping up a uni.
form body-temperature in spite of the
cold of winter. In the dormouse, mar.
mot and many allied forms, however,
rs also in the hedgehog and in bats, We
do find this winter sleep to occur. The
lower animals, such as reptiles, frogs
and efts, many fishes, spiders, shellfsll
and worms, also enter into this state
In preparing to hibernate, animals seek
secluded and sheltered hooks, or burrow
in the dry ground or in mud, or conceal
of trees. There they fall into sleep,
intervals of activity, which endures
more or less according to latitude and
consequent length of winter. During
this sleep the body heat of warm-b -blooded
animals falls greatly, US respiration and
circulation take place very gently and
slowly. The nutrition of the body is
also affected very slowly, the fat
of the body GENERALLY considerable
at the commencement of hiberna-
tion) being used up in the pro-
cess, unless occasional awaking has
given an opportunity for feeding. An
annual period of repose, analogous to
Information. also takes place during the
dry season in many tropical animals
as in many reptiles, frogs ard fishes.
| The tanrec, of Madagascar, which has q
superficial resemblance to the hedgehog,
also resembles it as to its annual torpor,
and certain lemuroids which inhabit the
same island, seem also to prepare for the
torpor of the dry season by storing up
a quantity of fat in their tails, which it
is alleged, disappears by the time the
period of activity has returned. Par
allel with the periodic repose of animals
is the winter inactivity Of many plants,
which (in temperate latitudes such as
our own) drop their leaves, or if herbs,
die down to shoot forth again with the
advent of spring. During this time the
sap retreats from the surface, and the
processes of life come almost to stand
still. to be renewed with rapidity and
suddenness not inaptly termed a "burst
of vegetation" at period which var.
les according to the species. The an
nual torpor of animals is a prolongation
for weeks or tor months of that process,
so familiar, yet so mysterious, called
sleep. During it the functions of life
are slackened in their operations, and
the refreshment which sleep produces is
not due to any accelerated nutrition,
but to a temporary cessation of the wear
and tear of activity.
The Immediate cause of sleep is not
yet satisfactorily known. 1t is init
mately connected with some condition
of the nervous centers, and it has been
supposed that its immediate cause was
4 diminished quantity of blood in the
brain; but as yet this view has not been
adequately supported by facts. During
sleep tue limbs are generally relaxed,
and the position assumed by the body
is often that which the embryo had
taken before birth. The nervous centers
are also more or less completely cut off
from external influences, the avenues of
special sense being more or less OBJ
structed by the position assumed by the
body, by the closure of the eyelids, etc.
Not only is this the case, but the very
stimuli received fail to excite re-
sponse unless they are ofmuch more than
ordinary intensity. Indeed, when ex-
haustion has been very great, and sleep
long deferred, the stimuli are powerless,
and the access of sleep becomes irresisti-
ble--as when Damiens slept on the rack.
Ordinarily, tae advent OF darkness is
the signal for sleep, but in nocturnal
animals the period of daily repose is in
verted. AS the process of refreshment,
induced by sleep, becomes more and
more perfected, slighter and slighter
stimulus is alone needed to awaken the
sleeper, till, at last, the mere changes of
organic life suffice to arouse the nerv-
Gus centers to their wonted activity
But although these centers are, during
sleep. more or less deprived Of COM
merce with the internal world, they
still maintain certain activity, rs
is evidenced by dreams which often
elicit sound and slight movements
even in the lower animals rs well as in
ourselves. 1t may, indeed, be that we
always dream when asleep. though our
dreams are generally forgotten immedi-
ately on awakening. This question can
not be absolutely determined, though
on the whole it seems more probable
that it is only in imperfect sleep that we
dream. That our nervous centers are
not entirely cut off from the external
world is proved by our dreams being
often influenced by sounds, smells or
touches. Indeed, a very active COM
merce with the external world must
take place n the abnormal sleep
of the sleep-walker, who may so
wonderfully adjust his movements
to varied conditions around him. A
mere local lethargy occurs in hypnot-
ism, when the patient not only sees,
hears and feels, but replies tosquestions
and exercises his imagination in re-
sponse to suggestions in the greatest
readiness, while remaining utterly
paralyzed as regards his voluntary
actions. Plants, since they have no
nervous system, can have nothing
really similar to the sleep of animals,
yet many plants assume special posi-
tions as to the parts of their frame with
the approach of night. Foliage leaves
will fold themselves, and flowers will
close. movements which as yet receive
no adequate explanation. -Contempor-
ary RevFew.