Richland beacon., 1873-02-22
Sleep.

The history of the opinions of physioio-
gists in regard to the cause of sleep pre-
sents an instructive example of the folly
of theOriZing on such a subject. in the
absence of any adequate basis of facts es-
tablished by observation. From the good
old times, when the ascension of vapOrs
from the stomach, their cOngelatiOn by |
the GOODNESS of the brain, and the conSe-
quent plugging of the vessels OF the head.
was deemed quite a lucid and satisfactory |
account of the matter, down TO compar-
atively recent period, there have been III |
Vulnerable opinions in regard to the cause
of sleep. The latest writer on the sub
ject, when setting up his own theory. de-
molished without difficulty those OF his
predecessors. At last the balance OF
scientific opinion. after many uncertain
oscillations, settled pretty steadily down
to the conviction, that the proXlmate
cause of sleep is state of funess or dis
tension of the bloOd-vesselS of the BRAIN.
Slumber is brought about, it was believed,
by pressure of the diStended vessels on
| the brain tissue. Though some men OF
| high standing could not rcprcSs their
! doubts that natural sleep is not caused III
| this way by a tight sanguneOus nightcap.
| this opinion was generally held, and the
dOubters could not give any better solu-
ton of the problem, but were rather in
cline,i to treat it as insOlublc. One thing
was certain: that a condition in some re-
spects resembling sleep could be artiiic'-
ally produced by pressure on the BRAIN:
This condition, though often identified
with sleep, was really its counterfeit
coma or stupOr, a state distinguishable
from true slumber by the great difficulty OF
arOusing the unfortunate subjects OF 1t.
This theory, after it had long held sway,
was at last proved to be at variance with
some established physiological principles
and with observations made on the brain
i'm cases where that organ had been eX'
posed by fracture of its bOny covering. II
was shown, besides, that a state in every
way resembling natural sleep could be Ill
duced by diminishing instead of increaS
ing the supply of blood to the brain. Ii
+ 1855. it occurred to DIR. Fleming, then ;
professor i'm Cork, to try the effect OF com
, pressing at the upper part OF the neck tht
/, carotid arteries. two of the vessels which
convey the vital fluid to the brain. fi
!, requested friend to make the experiment
! on himself. The result was the produc
: ton of state of complete unconscious
y ness, i'm which, however, the subject
; the somewhat hazardous expermen
y dreamed with great activity. few st
: conds appearing as hours, from the mum
: Der and rapid succession OF the Thought
:. passing through his mind. The effect
:. passed off on the removal of the pressrlr
: from the vessels. This was clearly
e very different condition from that
l. stupor. and one net distinguishable froI
ordinary sleep. DIR. + leming was caution
> i'm drawing conclusions, but he threw OF
N the suggestion that possibly after all o
Is binary sleep might be connected with
Al oppOsite cerebral condition to that con
Ie monty assigned as its cause. In fe
= wears this was placed beyond AL doub
u MIR. Durham, a London surgeon, anu
e most simultaneously DR.. Hammond
s. New York. showed, by a series OF ex, el
le ments on the lower animals, the resul
Q. of which were first published in lSGO, tn
IL during sleep the brain is in a compar
II, lively bloodless condition. The expel
al menters observed the brain becOmir
ne pale, and sinking down as sleep came OF
n, and as that condition passed of, they sa
III its surface rising up and becoming suifus
US with the red blush of the returning q
OF culation. At the period OF compile
ia awakening the vessels became more II
De and distended, and a large number spral
as into sight which had been invisible du
10 ing slumber. These experiments, VIII
Is viewed in connection with that OF L
re Fleming, formerly mentioned, prov
no cOnclusively that the immediate ante'
m dent of sleep is diminutiOn OF the stres
en- of blood flowing to the brain, which &C
IN ditiOn lasts uring the continuance
; a sleep.-Chambcr's Journal.