Year: 1866

sion upon the nerves-a blow, for exar


pie, or the prick of pin-is felt at tt


moment it is inflicted The nerves a


not the repositories of sensation; they al


but the conductors of the motion whic


produces sensation. The seat of sens


ton ID the brain, and to it the intelligenc


of any injury done to the nerves has to


transmitted, before that injury become


manifest in consciousness. The trans


mission, moreover, requires time, and til


consequece is, that wound, inflicted at


portion of the body distant from the brai


is more tardily appreciated than one in


fiicted adjacent to the brain BY an in


genious experimental arrangement, Helm


holtz has determined the velocity of ner


vous transmission both in warm bloode,


and old-blooded animals. In a frog, h.


found the velocity to be about eighty fee


a second, or less than one.thirteenth of th,


velocity of sound in air. If this hold


good, which it probably does, in the case


OF whale, then creature of this cIas


eighty feet long, if wounded in the tail


would not, as Helmholtz has remarked, be


conscious Of the injury till second after


the wound had been inflicted. But this


is not the only ingredient in the delay


that occurs between the impression on the


nerves and the consciousness of the i'm


preston. There can scarcely be doubt
that to every act of consciousness belongs
determinate molecular arrangement of
the brain-that every thought or feeling
has Its physical correlative in that organ !;
and nothing can be more certain than
that every physical change, whether mole
eular or mechanical, requires time for its
accomplishment. SO that even after the
intelligence OF an impression, made upon
distant portion of the body, has reach
ed the brain, still further time is neces-
sary for the brain itself to put its house
ID order-for its molecules to take up the
position necessary to the completion of
consciousness. Helmholtz considers one.
tenth of a second necessary for this pur
pose. Thus, in the case of the whale, we
have one second consumed in the trans
mission of intelligence through the censor
nerves from the tail to the head one
tenth of a second is required by the brain
to become conscious of the intelligence it
has received; and, if the velocity of trans
mission through the motor to the same as
that through the censor nerves, a second
would be consumed in sending a com
mand to the tail to defend itself. Thus
more than two seconds would elapse be-
fore an impression made upon its caudal
nerves could be responded to by whale
eighty feet long.


Now, it is quite conceivable that an in
Jury might be inflicted which would rem
der the nerves unfit to be the conductors
Of the motion which results in sensation :;
and if such thing occurred, no matter
how severe the injury might be, we should
not be conscious Of it. Or it may be, that
long before the time required for the brain
itself to complete the arrangement neces-
sary for the act Of consciousness, its pow
er of arrangement mi ght be wholly sus
pended. In such case alone, though the
injury might be of such a nature as to
cause death, this would occur not only
without pain, but absolutely without feel
lag of any kind. Death, in this case,
would be simply the sudden negation of
life, accomplished without any interven
ton Of consciousness. Doubtless, there
are many kinds of death of this character.
The passage of a musket bullet through
the brain Is case in point; and the placid
aspect of man thus killed is in perfect
accordance with the conclusion which
might be drawn q priOri from the exper-
ments of Helmholtz. Cases of insensi-
olllty, moreover, are not uncommon, which
10 not result in death, and after which
,he person affected has been able to testi |
y that no pain was felt prior to the loss
)f consciousness.


The time required for a rifle bullet to
pass through a mans head may be rough
y estimated at one-thousandth of sec |
md. Here, therefore, we should have no
'oom for sensation, and death would be |
painless. But there are other actions
which far transcend in rapidity that of the
life bullet. A flash Of lightning cleaves
cloud, appearing and disappearing in
ess than one-hundred thousanhth of
second and the velocity of electricity is
such as would carry it over distance
equal to that which separates the earth
nd moon in single second. 1t is well
lnown that luminous impression once
made upon the restina endures for about
,nesixth of second, and that this is the
'eason why we see ribbon of light when
| glowing coal is caused to pass rapidly
through the air. a body Illuminated by |
IN instantaneous flash continues to be |
cen for the sixth of second after the
lash has become extinct and if the BODY
hus Illuminated be in motion, it appears
It rest at the place which it occupied
when the fash fell upon it. The color
op is familiar to most Of us. BY this
Instrument disk with differently colored
ectors is caused to rotate rapidly the
'olors blend together, and if they are
'hosen in the proportions necessary to
orm white light, the disk appears white
When the motion is sufficiently rapid
Such a top, rotating in dark room, and