made by Prof. Barrett into cases of this kind, and that it is in
this direction we are to look for the explanation of many mysterious
phenomena formerly regarded as supernatural, but probably all
admitting (at least all that have been properly authenticated) of
being interpreted so soon as the circumstances on which consciousness
depends shall have been determined. Thus the following account of
experiments made at the village school in Westmeath seem especially
suggestive: 'Selecting some of the village children, and placing them
in a quiet room, giving each some small object to look at steadily,
he found one amongst the number who readily passed into a state of
reverie. In that state the subject could be made to believe the most
extravagant statements, such as that the table was a mountain, a
chair a pony, a mark on the floor, an insuperable obstacle. The girl
thus mesmerised passed on the second occasion into a state of deeper
sleep or trance, wherein no sensation whatever was experienced, unless
accompanied by pressure on the eyebrows of the subject. When the
pressure of the fingers was removed, the girl fell back in her chair
utterly unconscious of all around, and had lost all control over her
voluntary muscles. On reapplying the pressure, though her eyes remained
closed, she sat up and answered questions readily, but the manner in
which she answered them, her acts and expressions, were capable of
wonderful diversity, by merely altering the place on the head where the
pressure was applied. So sudden and marked were the changes produced
by a movement of the fingers, that the operation seemed very like
playing on some musical instrument. On a third occasion the subject,
after passing through these, which have been termed the biological
and phrenological states, became at length keenly and wonderfully
sensitive to the voice and acts of the operator. It was impossible for
the latter to call the girl by her name, however faintly and inaudibly
to those around, without at once eliciting a prompt response. If the
operator tasted, smelt, or touched anything, or experienced any sudden
sensation of warmth or cold, a corresponding effect was produced on
the subject, though nothing was said, nor could the subject have seen
what had occurred to the operator. To be assured of this he bandaged
the girl's eyes with great care, and the operator having gone behind
the girl to the other end of the room, he watched him and the girl, and
repeatedly assured himself of this fact.' Thus far, Professor Barrett's
observations, depending in part on what the operator experienced, may
be open to just so much doubt as may affect our opinion of the veracity
of a person unknown; but in what follows we have his own experience
alone to consider. 'Having mesmerised the girl himself, he took a card
at random from a pack which was in a drawer in another room. Glancing
at the card to see what it was, he placed it within a book, and in that
state brought it to the girl. Giving her the closed book, he asked
her to tell him what he had put within its leaves. She held the book
close to the side of her head, and said, 'I see something inside with
red spots on it; and she afterwards said there were five red spots on
it. The card was the five of diamonds. The same result occurred with
another card; and when an Irish bank-note was substituted for the card,
she said, 'Oh, now I see a number of heads--so many that I cannot
count them.' He found that she sometimes failed to guess correctly,
asserting that the things were dim; and she could give no information
of what was within the book unless he had previously known what it
was himself. More remarkable still, he asked her to go in imagination
to Regent Street, in London, and tell him what shops she had seen.
The girl had never been out of her remote village, but she correctly
described to him Mr. Ladd's shop, of which he happened to be thinking,
and mentioned the large clock that overhangs the entrance to Beak
Street. In many other cases he convinced himself that the existence of
a distinct idea in his own mind gave rise to an image of the idea (that
is, to a corresponding image) on the mind of the subject; not always
a clear image, but one that could not fail to be recognised as a more
or less distorted reflection of his own thought.' It is important to
notice the limit which a scientific observer thus recognised in the
range of the subjects' perception. It has been stated that subjects
in this condition have been able to describe occurrences not known to
any person, which yet have been subsequently verified. Although some
narratives of the kind have come from persons not likely to relate
what they _knew_ to be untrue, the possibility of error outweighs the
probability that such narratives can really be true. There is a form
of unconscious cerebration by which untruthful narratives come to be
concocted in the mind. For instance, Dr. Carpenter heard a scrupulously
conscientious lady asseverate that a table 'rapped' when nobody was
within a yard of it; but the story was disproved by the lady herself,
who found from her note-book, recording what really took place, that
the hands of six persons rested on the table when it rapped. And apart
from the unconscious fiction-producing power of the mind, there is
always the possibility, nay, often the extreme probability, that the
facts of a case may be misunderstood. Persons may be supposed to know
nothing about an event who have been conscious of its every detail;
nay, a person may himself be unconscious of his having known, and in
fact of his really knowing, of a particular event. Dual consciousness
in this particular sense is a quite common experience, as, for
instance, when a story is told us which we receive at first as new,
until gradually the recollection dawns upon us and becomes momentarily
clearer and clearer, not only that we have heard it before, but of the
circumstances under which we heard it, and even of details which the
narrator from whom a few moments before we receive it as a new story
has omitted to mention.[22]
The most important of all the questions depending on dual consciousness
is one into which I could not properly enter at any length in these
pages--the question, namely, of the relation between the condition of
the brain and responsibility, whether such responsibility be considered
with reference to human laws or to a higher and all-knowing tribunal.
But there are some points not wanting in interest which may be here
more properly considered.
In the first place it is to be noticed that a person who has passed
into a state of abnormal consciousness, or who is in the habit of doing
so, can have no knowledge of the fact in his normal condition except
from the information of others. The boy at Norwood might be told of
what he had said and done while in his less usual condition, but so
far as any experience of his own was concerned, he might during all
that time have been in a profound sleep. Similarly of all the other
cases. So that we have here the singular circumstance to consider, that
a person may have to depend on the information of others respecting
his own behaviour--not during sleep or mental aberration or ordinary
absence of mind--but (in some cases at least) while in possession of
all his faculties and unquestionably responsible for his actions. Not
only might a person find himself thus held responsible for actions
of which he had no knowledge, and perhaps undeservedly blamed or
condemned, but he might find himself regarded as untruthful because of
his perfectly honest denial of all knowledge of the conduct attributed
to him. If such cases were common, again, it would not improbably
happen that the simulation of dual consciousness would become a
frequent means of attempting to evade responsibility.
Another curious point to be noticed is this. Supposing one subject
to alternations of consciousness were told that in his abnormal
condition he suffered intense pain or mental anguish in consequence
of particular actions during his normal state, how far would he be
influenced to refrain from such actions by the fear of causing pain
or sorrow to his 'double,' a being of whose pains and sorrows, nay,
of whose very existence, he was unconscious? In ordinary life a man
refrains from particular actions which have been followed by unpleasant
consequences, reasoning, in some cases, 'I will not do so-and-so,
because I suffered on such and such occasions when I did so' (we set
religious considerations entirely on one side by assuming that the
particular actions are not contrary to any moral law), in others, 'I
will not do so-and-so because my so doing on former occasions has
caused trouble to my friend A or B:' but it is strange to imagine any
one reasoning, 'I will not do so-and-so because my so doing on former
occasions has caused my second self to experience pain and anguish,
of which I myself have not the slightest recollection.' A man may
care for his own well-being, or be unwilling to bring trouble on his
friends, but who is that second self that his troubles should excite
the sympathy of his fellow-consciousness? The considerations here
touched on are not so entirely beyond ordinary experience as might be
supposed. It may happen to any man to have occasion to enter into an
apparently unconscious condition during which in reality severe pains
may be suffered by another self, though on his return to his ordinary
condition no recollection of those pains may remain, and though to all
appearance he has been all the time in a state of absolute stupor; and
it may be a reasonable question, not perhaps whether he or his double
shall suffer such pains, but whether the body which both inhabit will
suffer while he is unconscious, or while that other consciousness comes
into existence. That this is no imaginary supposition is shown by
several cases in Abercrombie's treatise on the 'Intellectual Powers.'
Take, for instance, the following narrative:--'A boy,' he tells us, 'at
the age of four suffered fracture of the skull, for which he underwent
the operation of the trepan. He was at the time in a state of perfect
stupor, and after his recovery retained no recollection either of the
accident or of the operation. At the age of fifteen, however, during
the delirium of fever, he gave his mother an account of the operation,
and the persons who were present at it, with a correct description of
their dress, and other minute particulars. He had never been observed
to allude to it before; and no means were known by which he could
have acquired the circumstances which he mentioned.' Suppose one day
a person in the delirium of fever or under some other exciting cause
should describe the tortures experienced during some operation, when,
under the influence of anæsthetics, he had appeared to all around to be
totally unconscious, dwelling in a special manner perhaps on the horror
of pains accompanied by utter powerlessness to shriek or groan, or even
to move; how far would the possibilities suggested by such a narrative
influence one who had a painful operation to undergo, knowing as he
would quite certainly, that whatever pains his _alter ego_ might have
to suffer, not the slightest recollection of them would remain in his
ordinary condition?
There is indeed almost as strange a mystery in unconsciousness as there
is in the phenomena of dual consciousness. The man who has passed for
a time into unconsciousness through a blow, or fall, or fit, cannot
help asking himself like Bernard Langdon in that weird tale, Elsie
Venner, 'Where was the mind, the soul, the thinking principle all that
time?' It is irresistibly borne in upon him that he has been dead for
a time. As Holmes reasons, 'a man is stunned by a blow and becomes
unconscious, another gets a harder blow and it kills him. Does he
become unconscious too? If so, _when_, and _how does he come to his
consciousness_? The man who has had a slight and moderate blow comes
to himself when the immediate shock passes off and the organs begin to
work again, or when a bit of the skull is "pried" up, if that happens
to be broken. Suppose the blow is hard enough to spoil the brain and
stop the play of the organs, what happens then?' So far as physical
science is concerned, there is no answer to this question; but physical
science does not as yet comprehend all the knowable, and the knowable
comprehends not all that has been, is, and will be. What we know and
can know is nothing, the unknown and the unknowable are alike infinite.
FOOTNOTES:
[Footnote 21: Should any doubt whether these conditions of dual
existence are a reality (a doubt, however, which the next case dealt
with in the text should remove), we would remind them that a similar
difficulty unmistakably existed in the case of Eng and Chang, the
Siamese twins. It would have been almost impossible to inflict any
punishment on one by which the other would not have suffered, and
capital punishment inflicted on one would have involved the death of
the other.]
[Footnote 22: An instance of the sort turns up in Pope's correspondence
with Addison, and serves to explain a discrepancy between Tickell's
edition of the _Spectator_ and the original. In No. 253, Addison had
remarked that none of the critics had taken notice of a peculiarity in
the description of Sisyphus lifting his stone up the hill, which is
no sooner carried to the top of it but it immediately tumbles to the
bottom. 'This double motion,' says Addison, 'is admirably described
in the numbers of those verses. In the four first it is heaved up by
several spondees intermixed with proper breathing places, and at last
trundles down in a continual line of dactyls.' On this Pope remarks:
'I happened to find the same in Dionysius of Halicarnassus's Treatise,
who treats very largely upon these verses. I know you will think fit to
soften your expression, when you see the passage, which you must needs
have read, though it be since slipt out of your memory.' These words,
by the way, were the last (except 'I am, with the utmost esteem, &c.')
ever addressed by Pope to Addison. It was in this letter that Pope
with sly malice asked Addison to look over the first two books of his
(Pope's) translation of Homer.]
_ELECTRIC LIGHTING._
Although we certainly have no reason to complain of the infrequency
of attempts in newspapers, &c., as well as in scientific journals, to
explain the principles on which electric lighting depends, it does
not seem that very clear ideas are entertained on this subject by
unscientific persons. Nor is this, perhaps, to be wondered at, when
we observe that in nearly all the explanations which have appeared,
technical expressions are quite freely used, while those matters
about which the general reader especially desires information are
passed over as points with which every one is familiar. Now, without
going quite so far as to say that there is no exaggeration in the
picture presented some time back in _Punch_, of one who asked whether
the electric fluid was 'anything like beer, for instance,' I may
confidently assert that the very vaguest notions are entertained by
nine-tenths of those who hear about the electric light, respecting
the nature of electricity. Of course, I am not here referring to the
doubts and difficulties of electricians on this subject. It is well
known that Faraday, after a life of research into electrical phenomena,
said that when he had studied electricity for a few years he thought
he understood much, but when he had nearly finished his observational
work he found he knew nothing. In the sense in which Faraday spoke, the
most advanced students of science must admit that they know nothing
about electricity. But the greater number of those who read about
the electric light are not familiar even with electrical phenomena,
as distinguished from the interpretation of such phenomena. I am
satisfied that there is no exaggeration in a passage which appeared
recently in the 'Table Talk' of the _Gentleman's Magazine_, describing
an account of the electric light as obtained from some new kind of gas,
carried in pipes from central reservoirs, and chiefly differing from
common gas in this, that the heat resulting from its consumption melted
ordinary burners, so that only burners of carbon or platinum could be
safely employed.
I do not propose here to discuss, or even to describe (in the proper
sense of the word) the various methods of electric lighting which
have been either used or suggested. What I wish to do is to give a
simple explanation of the general principles on which illumination by
electricity depends, and to consider the advantages which this method
of illumination appears to promise or possess.
Novel as the idea of using electricity for illuminating large spaces
may appear to many, we have all of us been long familiar with the
fact that electricity is capable of replacing the darkness of night
by the light of broad day over areas far larger than those which our
electricians hope to illuminate. The lightning flash makes in an
instant every object visible on the darkest night, not only in the
open air, but in the interior of carefully darkened rooms. Nay, even
if the shutters of a room are carefully closed and the room strongly
illuminated, the lightning flash can yet be clearly recognised.
And it must be remembered that though the suddenness of the flash
makes us the more readily perceive it (under such circumstances, for
instance), yet its short duration diminishes its apparent intensity.
This may appear a contradiction in terms, but is not so in reality. The
perception that there has been a sudden lighting up of the sky or of a
room, is distinct from the recognition of the actual intensity of the
illumination thus momentarily produced. Now it is quite certain that
the eye cannot assign less than a twenty-fifth of a second or so to the
duration of the lightning flash, for, as Newton long since showed, the
retina retains the sensation of light for at least this interval after
the light has disappeared. It is equally certain, from Wheatstone's
experiments, that the lightning flash does not actually endure for the
100,000th part of a second. Adopting this last number, though it falls
far short of the truth--the actual duration being probably less than
1,000,000th of a second--we see that so far as the eye is concerned, an
amount of light which was really emitted during the 100,000th part of
a second is by the eye judged to have been emitted during an interval
4,000 times as long. It is certain, then, that the eye's estimate of
the intensity of the illumination resulting from a lightning flash is
far short of the truth. This is equally true even in those cases where
lightning is said to be for awhile continuous. If the flashes for a
time succeed each other at less intervals than a twenty-fifth of a
second, the illumination will appear continuous. But it is not really
so. To be so, the flashes should succeed each other at the rate of at
least 100,000, and probably of more than 1,000,000 per second.
While the lightning flash shows the brilliancy which the electric
illumination can attain, it shows also the intense heat resulting from
the electric discharge. This might, indeed, be inferred simply from the
brilliancy of the light, since we know that this brilliancy can only be
due to the intense heat to which the particles along the track of the
electric flash have been raised. But it is shown in a more convincing
manner to ordinary apprehension by the effects which the lightning
flash produces where--in the common way of speaking--it strikes. The
least fusible substances are melted. Effects are produced also which,
though at first not seemingly attributable to intense heat, yet in
reality can be no otherwise explained. Thus, when the trunk of a tree
is torn into fragments by the lightning stroke, though the tree is
scorched and blackened, a small amount of heat would account for that
particular effect, while the destruction of the tree seems attributable
to mechanical causes. It is, indeed, from effects such as these that
the idea of the fall of thunderbolts has doubtless had its origin,
the notion being that some material substance has struck the body thus
shattered or destroyed. In reality, however, such destructive effects
are due entirely to the intense heat excited during the passage of
the electricity. Thus, in the case of a tree destroyed by lightning,
the shattering of boughs and trunk results from the sudden conversion
of the moisture of the tree (that is, the moisture present in the
substance of the tree) into steam, a change accompanied of course by
great and sudden expansion. The tree is as certainly destroyed by the
effects of heat as is a boiler which has burst, though in each case the
expansive power of steam directly works the mischief.
It is the more useful for our present purpose thus to note at the
outset both the illuminating and the heating power of the lightning
flash (or rather of the electric discharge), because, as will presently
be seen, the electric light, while in all cases depending on intensity
of heat, may either be obtained in the form of a series of flashes
succeeding each other so quickly as to be to all intents and purposes
continuous, or from the incandescence of some suitable substance in the
path of the electric current.
Let us now consider briefly the general nature of electrical phenomena,
or at least of those electrical phenomena which are related to our
present subject.
Formerly, when light was supposed to be a material emanation, and
heat was regarded as an actual fluid, electricity was in like manner
regarded as some subtle fluid which could be generated or dispersed
in various ways. At present, it is safer to speak of electricity
as a state or condition of matter. If it were not that some very
eminent electricians (and one especially whose eminence as a practical
electrician is very great) are said to believe still that there is such
a thing as an electric fluid, we should have simply asserted that in
the present position of scientific research, with the known velocity
at which the so-called electric current flows, and the known relations
between electricity, heat, and light, the theory of an electric fluid
is altogether untenable. It will suffice, however, under the actual
circumstances, to speak simply of electrical properties, without
expressing any definite opinion respecting their interpretation.
A certain property, called electricity, is excited in any substance by
any cause affecting the condition of the substance, whether that cause
be mechanical, chemical, thermal, or otherwise. No change can take
place in the physical condition of any body without the generation of
a greater or less amount of electricity, although in far the greater
number of cases there may be no obvious evidence of the fact, while in
many cases no evidence may be obtainable even by the use of the most
delicate scientific tests.
I have spoken here of the generation of a greater or less amount of
electricity, but in reality it would be more correct to speak simply
of a change in the electrical condition of the substance. Electricians
speak of positive and negative electricity as though there actually
were two distinct forms of this peculiar property of matter. But it
may be questioned whether it would not be more correct to speak of
electricity as we do of heat. We might speak of cold as negative heat
precisely as electricians give the name of negative electricity to a
relative deficiency of what they call positive electricity; but in
the case of heat and cold it is found more convenient, and is more
correct, to speak of different degrees of one and the same quality. The
difficulty in the case of electricity is that at present science has
no means of deciding whether positive or negative electricity has in
reality the better claim to be regarded as absolute electricity. Making
comparison between electrical and thermal relations, the process which
we call the generation of positive electricity may in reality involve
the dispersion of absolute electricity, and so correspond to cooling,
not to heating. In this case the generation of what we call negative
electricity would in reality be the positive process. However, it is
not necessary to discuss this point, nor can any error arise from the
use of the ordinary method of expression, so long as we carefully hold
in remembrance that it is only employed for convenience, and must not
be regarded as scientifically precise.
Electricity may be excited, as I have said, in many ways. With the
ordinary electrical machine it is excited by the friction of a glass
disc or cylinder against suitable rubbers of leather and silk. The
galvanic battery developes electricity by the chemical action of acid
solutions on metal plates. We may speak of the electricity generated
by a machine as frictional electricity, and of that generated by
a galvanic battery as voltaic electricity; in reality, however,
these are not different kinds of electricity, but one and the same
property developed in different ways. The same also is the case with
magnetic electricity, of which I shall presently have much to say:
it is electricity produced by means of magnets, but is in no respect
different from frictional or voltaic electricity. Of course, however,
it will be understood that for special purposes one method of producing
electricity may be more advantageously used than another. Just as heat
produced by burning coal is more convenient for a number of purposes
than heat produced by burning wood, though there is no scientific
distinction between coal-produced heat and wood-produced heat, so for
some purposes voltaic electricity is more convenient than frictional
electricity, though there is no real distinction between them.