STILL MORE THEORIES
Sleep sits upon his brow;
His eye is closed; he sleeps, nor dreams of harm.
LONGFELLOW.
We have not yet exhausted all the theories, nor shown how much too much
some of them and how far too little all of them prove.
The two remaining scientific theories of sleep are the psychological
and the biological. The best modern exponent of the psychological
theory is Marie de Manacéïne, who defines sleep as “the resting-time
of consciousness.” Persons whose consciousness is but little developed,
young children, and those of weak intellect, usually require a great
deal of sleep, while persons whose minds are active, alert, responsive,
get along with comparatively little sleep.
For a long time it was believed that living creatures devoid of
consciousness would not sleep at all, but recent experiments have
apparently weakened that conclusion. Dogs, pigeons, and other animals
deprived of brains in the interest of scientific discovery, appear to
sleep, that is, they have periods of inactivity, just as those with
brains and consciousness. Belmondo, after repeated experiments, drew
the conclusion that sleep is not a purely cerebral function, as some
believe, but that the whole organism sleeps; and the brain sleeps only
because the organs of sense sleep. This, however, is doubtful.
And this is in sum and substance the biological theory of sleep,
that the whole organism sleeps, but even here there are exceptions.
It is true that the heart beats less rapidly; that we breathe less
frequently; that the brain cells cease their functioning because the
neuroglia contracts and shuts off or lessens their joint activity;
the motor consciousness rests; the nerves of sensation refuse to be
stimulated, we sleep. Yet we know that the spinal cord never sleeps,
that certain functions of the body continue uninterruptedly in the
sleeping-state as in the waking-state, and, after all these years of
theorizing and experimenting, we do not know definitely what sleep is.
We know the mechanism of sleep, its manifestations and its effects;
we know that continued sleeplessness means madness and death; that
sleep is essential to the physical and mental well-being of the human
organism, but we do not know what sleep is any more than we know what
life is. There is a limit to what material science can know.
Heubel, who is one of the recent supporters of the psychological
theory of sleep, says that “Mental activity depends on the incoming
peripheral sensory stimulations; when such peripheral sensory
stimulations are absent, mental activity is in abeyance and sleep
results.” This is, in effect, to say that, when things about us no
longer give us any sensation, when they do not attract or hold our
attention, we fall asleep. But we all know of exceptions to this rule.
We have seen others fall into “a brown study,” and have probably done
so ourselves, and become perfectly lost to all about them; absorbed in
their own reflections, they neither hear nor see the things happening
around them. For the time being “peripheral sensory stimulations” are
absent, and yet mental activity continues and sleep does not result.
The biological theory of sleep considers all the other theories, while
formulating its own, because biology considers the whole organism and
not only one organ or function of the body. From a different point of
view Binns’ theory is confirmed by Claperède, who points out that,
“biologically regarded, sleep has its significance not as a passive
state, but as an active instinct, like all the other instincts of
animal life.” There is a degree of satisfaction to be found in this
theory. It might be stated in this way, that, when man has had during
any period all the sensations and experiences he can digest, the
instinct to sleep takes possession of him. It is not that he becomes
helpless in the hands of those experiences, but that his whole nature,
like his stomach, knows when it has had food enough, and desires time
for digestion and assimilation before it takes in more. Obviously,
“utter separation from the phenomenal world,” as John Bigelow expresses
it, becomes necessary.
In his lectures on Botany at the Royal School of Medicine in Great
Britain, Professor Leo H. Grindon said: “Man is captured in sleep not
by death but by his better nature; to-day runs in through a deeper day
to become the parent of to-morrow, and to issue every morning, bright
as the morning of life, and of life-size, from the peaceful womb of
the cerebellum.” This is the result not of a passive state, but of an
active instinct; it accepts sleep as a time of growth, not merely a
time of rest. Bigelow says, “Something goes on during sleep which is
a preventive as well as an antidote to mania,” and, in furtherance of
this same idea, Dr. J. J. G. Wilkinson of the Royal College of Surgeons
of London, argues that it seems “as if a reason more perfect than
reason, and uninfluenced by its partialities, had been at work when
we were in our beds.” Even “biologically regarded,” Bigelow is not
far astray when he claims that “our desire for sleep is manifestly
designed to promote in us the growth and development of spiritual
graces.” In other words, we desire to sleep, that we may relate the
experiences of our every-day active life to the sum of knowledge we
already possess by inheritance and past experience, that we may thereby
get a fuller understanding of life and its purposes.
“It is not uncommon for those who have no habit or inclination
to sleep during the morning hours of secular days, to be overcome
with somnolency in church soon after the devotional exercises are
begun, and to find it impossible to derive any edification from them
until they have lost themselves for a moment or two in absolute
unconsciousness. Then they have no difficulty, sometimes a lively
pleasure, in attending to the exercises which follow. The worshiper is
then withdrawn from the familiar excitement of customary avocations.
It is idle to suppose that in these few moments of repose, upright
in his pew, he has rested enough, in the common acceptation of that
word, to repair any waste of tissue that would explain the new sense
of refreshment that ensues. He has received, in that brief retirement
from the world, some reinforcements which manifestly are not dependent
upon time or space for their efficacy—spiritual reinforcements, and
spiritual reinforcements only. He has removed himself, or been removed,
further away, out of sight or hearing or thinking, so to speak, of
his phenomenal life, and nearer to the Source of all life.” This
explanation may or may not be true. He adds:
“It was quite a common impression among the ancients that sleepers
in temples of religion were more apt to receive divine communications
there than elsewhere.” (“Mystery of Sleep,” John Bigelow, pp. 94-95.)