The Science Of Deduction
We met next day as he had arranged, and in-
spected the rooms at No. 221b, Baker Street, of
which he had spoken at our meeting. They con-
sisted of a couple of comfortable bed-rooms and a
single large airy sitting-room, cheerfully furnished,
and illuminated by two broad windows. So de-
sirable in every way were the apartments, and so
moderate did the terms seem when divided be-
tween us, that the bargain was concluded upon the
spot, and we at once entered into possession. That
very evening I moved my things round from the ho-
tel, and on the following morning Sherlock Holmes
followed me with several boxes and portmanteaus.
For a day or two we were busily employed in un-
packing and laying out our property to the best
advantage. That done, we gradually began to settle
down and to accommodate ourselves to our new
surroundings.
Holmes was certainly not a difficult man to live
with. He was quiet in his ways, and his habits were
regular. It was rare for him to be up after ten at
night, and he had invariably breakfasted and gone
out before I rose in the morning. Sometimes he
spent his day at the chemical laboratory, sometimes
in the dissecting-rooms, and occasionally in long
walks, which appeared to take him into the low-
est portions of the City. Nothing could exceed his
energy when the working fit was upon him; but
now and again a reaction would seize him, and
for days on end he would lie upon the sofa in the
sitting-room, hardly uttering a word or moving a
muscle from morning to night. On these occasions
I have noticed such a dreamy, vacant expression
in his eyes, that I might have suspected him of be-
ing addicted to the use of some narcotic, had not
the temperance and cleanliness of his whole life
forbidden such a notion.
As the weeks went by, my interest in him and
my curiosity as to his aims in life, gradually deep-
ened and increased. His very person and appear-
ance were such as to strike the attention of the most
casual observer. In height he was rather over six
feet, and so excessively lean that he seemed to be
considerably taller. His eyes were sharp and pierc-
ing, save during those intervals of torpor to which I
have alluded; and his thin, hawk-like nose gave his
whole expression an air of alertness and decision.
His chin, too, had the prominence and squareness
which mark the man of determination. His hands
were invariably blotted with ink and stained with
chemicals, yet he was possessed of extraordinary
delicacy of touch, as I frequently had occasion to observe when I watched him manipulating his fragile
philosophical instruments.
The reader may set me down as a hopeless busybody, when I confess how much this man stimu lated my curiosity, and how often I endeavoured to
break through the reticence which he showed on all
that concerned himself. Before pronouncing judgment, however, be it remembered, how objectless
was my life, and how little there was to engage my
attention. My health forbade me from venturing
out unless the weather was exceptionally genial,
and I had no friends who would call upon me and
break the monotony of my daily existence. Under
these circumstances, I eagerly hailed the little mystery which hung around my companion, and spent
much of my time in endeavouring to unravel it.
He was not studying medicine. He had him-
self, in reply to a question, confirmed Stamford’s
opinion upon that point. Neither did he appear to
have pursued any course of reading which might fit
him for a degree in science or any other recognized
portal which would give him an entrance into the
learned world. Yet his zeal for certain studies was
remarkable, and within eccentric limits his knowl-
edge was so extraordinarily ample and minute that
his observations have fairly astounded me. Surely
no man would work so hard or attain such precise
information unless he had some definite end in
view. Desultory readers are seldom remarkable for
the exactness of their learning. No man burdens
his mind with small matters unless he has some
very good reason for doing so.
His ignorance was as remarkable as his knowledge. Of contemporary literature, philosophy and
politics he appeared to know next to nothing. Upon
my quoting Thomas Carlyle, he inquired in the
naivest way who he might be and what he had
done. My surprise reached a climax, however,
when I found incidentally that he was ignorant
of the Copernican Theory and of the composition
of the Solar System. That any civilized human be-
ing in this nineteenth century should not be aware
that the earth travelled round the sun appeared to
be to me such an extraordinary fact that I could
hardly realize it.
“You appear to be astonished,” he said, smiling
at my expression of surprise. “Now that I do know
it I shall do my best to forget it.”
“To forget it!”
“You see,” he explained, “I consider that a
man’s brain originally is like a little empty attic,
and you have to stock it with such furniture as you
choose. A fool takes in all the lumber of every sort
that he comes across, so that the knowledge which
might be useful to him gets crowded out, or at best
is jumbled up with a lot of other things so that he
has a difficulty in laying his hands upon it. Now
the skilful workman is very careful indeed as to
what he takes into his brain-attic. He will have
nothing but the tools which may help him in doing
his work, but of these he has a large assortment,
and all in the most perfect order. It is a mistake to
think that that little room has elastic walls and can
distend to any extent. Depend upon it there comes
a time when for every addition of knowledge you
forget something that you knew before. It is of the
highest importance, therefore, not to have useless
facts elbowing out the useful ones.”
“But the Solar System!” I protested.
“What the deuce is it to me?” he interrupted
impatiently; “you say that we go round the sun.
If we went round the moon it would not make a
pennyworth of difference to me or to my work.”
I was on the point of asking him what that work
might be, but something in his manner showed
me that the question would be an unwelcome one.
I pondered over our short conversation, however,
and endeavoured to draw my deductions from it.
He said that he would acquire no knowledge which
did not bear upon his object. Therefore all the
knowledge which he possessed was such as would
be useful to him. I enumerated in my own mind
all the various points upon which he had shown
me that he was exceptionally wellinformed. I even
took a pencil and jotted them down. I could not
help smiling at the document when I had com-
pleted it. It ran in this way—
Sherlock Holmes—his limits.
1. Knowledge of Literature.—Nil.
2. Philosophy.—Nil.
3. Astronomy.—Nil.
4. Politics.—Feeble.
5. Botany.—Variable. Well up in belladonna,
opium, and poisons generally. Knows noth-
ing of practical gardening.
6. Geology.—Practical, but limited. Tells at a
glance different soils from each other. Af-
ter walks has shown me splashes upon his
trousers, and told me by their colour and
consistence in what part of London he had
received them.
7. Chemistry.—Profound.
8. Anatomy.—Accurate, but unsystematic.
9. Sensational Literature.—Immense. He ap-
pears to know every detail of every horror
perpetrated in the century.
10. Plays the violin well.
11. Is an expert singlestick player, boxer, and
swordsman.
12. Has a good practical knowledge of British
law
When I had got so far in my list I threw it into
the fire in despair. “If I can only find what the
fellow is driving at by reconciling all these accom-
plishments, and discovering a calling which needs
them all,” I said to myself, “I may as well give up
the attempt at once.”
I see that I have alluded above to his powers
upon the violin. These were very remarkable, but as
eccentric as all his other accomplishments. That he
could play pieces, and difficult pieces, I knew well,
because at my request he has played me some of
Mendelssohn’s Lieder, and other favourites. When
left to himself, however, he would seldom produce
any music or attempt any recognized air. Leaning
back in his arm-chair of an evening, he would close
his eyes and scrape carelessly at the fiddle which
was thrown across his knee. Sometimes the chords
were sonorous and melancholy. Occasionally they
were fantastic and cheerful. Clearly they reflected
the thoughts which possessed him, but whether
the music aided those thoughts, or whether the
playing was simply the result of a whim or fancy
was more than I could determine. I might have
rebelled against these exasperating solos had it not
been that he usually terminated them by playing
in quick succession a whole series of my favourite
airs as a slight compensation for the trial upon my
patience.
During the first week or so we had no callers,
and I had begun to think that my companion was
as friendless a man as I was myself. Presently, how-
ever, I found that he had many acquaintances, and
those in the most different classes of society. There
was one little sallow rat-faced, dark-eyed fellow
who was introduced to me as Mr. Lestrade, and
who came three or four times in a single week. One
morning a young girl called, fashionably dressed,
and stayed for half an hour or more. The same after-
noon brought a grey-headed, seedy visitor, looking
like a Jew pedlar, who appeared to me to be much
excited, and who was closely followed by a slip-
shod elderly woman. On another occasion an old
white-haired gentleman had an interview with my
companion; and on another a railway porter in his
velveteen uniform. When any of these nondescript
individuals put in an appearance, Sherlock Holmes
used to beg for the use of the sitting-room, and I
would retire to my bed-room. He always apolo-
gized to me for putting me to this inconvenience.
“I have to use this room as a place of business,”
he said, “and these people are my clients.” Again
I had an opportunity of asking him a point blank
question, and again my delicacy prevented me from
forcing another man to confide in me. I imagined
at the time that he had some strong reason for not
alluding to it, but he soon dispelled the idea by
coming round to the subject of his own accord.
It was upon the 4th of March, as I have good
reason to remember, that I rose somewhat earlier
than usual, and found that Sherlock Holmes had
not yet finished his breakfast. The landlady had
become so accustomed to my late habits that my
place had not been laid nor my coffee prepared.
With the unreasonable petulance of mankind I rang
the bell and gave a curt intimation that I was ready.
Then I picked up a magazine from the table and
attempted to while away the time with it, while my
companion munched silently at his toast. One of
the articles had a pencil mark at the heading, and I
naturally began to run my eye through it.
Its somewhat ambitious title was “The Book of
Life,” and it attempted to show how much an obser-
vant man might learn by an accurate and systematic
examination of all that came in his way. It struck me
as being a remarkable mixture of shrewdness and
of absurdity. The reasoning was close and intense,
but the deductions appeared to me to be far-fetched
and exaggerated. The writer claimed by a momen-
tary expression, a twitch of a muscle or a glance of
an eye, to fathom a man’s inmost thoughts. Deceit,
according to him, was an impossibility in the case
of one trained to observation and analysis. His con-
clusions were as infallible as so many propositions
of Euclid. So startling would his results appear to
the uninitiated that until they learned the processes
by which he had arrived at them they might well
consider him as a necromancer.
“From a drop of water,” said the writer, “a logi-
cian could infer the possibility of an Atlantic or a
Niagara without having seen or heard of one or the
other. So all life is a great chain, the nature of which
is known whenever we are shown a single link of
it. Like all other arts, the Science of Deduction
and Analysis is one which can only be acquired
by long and patient study nor is life long enough
to allow any mortal to attain the highest possi-
ble perfection in it. Before turning to those moral
and mental aspects of the matter which present
the greatest difficulties, let the enquirer begin by
mastering more elementary problems. Let him, on
meeting a fellow-mortal, learn at a glance to dis-
tinguish the history of the man, and the trade or
profession to which he belongs. Puerile as such
an exercise may seem, it sharpens the faculties of
observation, and teaches one where to look and
what to look for. By a man’s finger nails, by his
coat-sleeve, by his boot, by his trouser knees, by the
callosities of his forefinger and thumb, by his ex-
pression, by his shirt cuffs—by each of these things
a man’s calling is plainly revealed. That all united
should fail to enlighten the competent enquirer in
any case is almost inconceivable.”
“What ineffable twaddle!” I cried, slapping the
magazine down on the table, “I never read such
rubbish in my life.”
“What is it?” asked Sherlock Holmes.
“Why, this article,” I said, pointing at it with
my egg spoon as I sat down to my breakfast. “I see
that you have read it since you have marked it. I
don’t deny that it is smartly written. It irritates me
though. It is evidently the theory of some arm-chair
lounger who evolves all these neat little paradoxes
in the seclusion of his own study. It is not practical.
I should like to see him clapped down in a third
class carriage on the Underground, and asked to
give the trades of all his fellow-travellers. I would
lay a thousand to one against him.”
“You would lose your money,” Sherlock Holmes
remarked calmly. “As for the article I wrote it my-
self.”
“You!”
“Yes, I have a turn both for observation and for
deduction. The theories which I have expressed
there, and which appear to you to be so chimerical
are really extremely practical—so practical that I
depend upon them for my bread and cheese.”
“And how?” I asked involuntarily.
“Well, I have a trade of my own. I suppose I am
the only one in the world. I’m a consulting detec-
tive, if you can understand what that is. Here in
London we have lots of Government detectives and
lots of private ones. When these fellows are at fault
they come to me, and I manage to put them on the
right scent. They lay all the evidence before me,
and I am generally able, by the help of my knowl-
edge of the history of crime, to set them straight.
There is a strong family resemblance about mis-
deeds, and if you have all the details of a thousand
at your finger ends, it is odd if you can’t unravel
the thousand and first. Lestrade is a well-known
detective. He got himself into a fog recently over a
forgery case, and that was what brought him here.”
“And these other people?”
“They are mostly sent on by private inquiry
agencies. They are all people who are in trouble
about something, and want a little enlightening. I
listen to their story, they listen to my comments,
and then I pocket my fee.”
“But do you mean to say,” I said, “that with-
out leaving your room you can unravel some knot
which other men can make nothing of, although
they have seen every detail for themselves?”
“Quite so. I have a kind of intuition that way.
Now and again a case turns up which is a little
more complex. Then I have to bustle about and
see things with my own eyes. You see I have
a lot of special knowledge which I apply to the
problem, and which facilitates matters wonderfully.
Those rules of deduction laid down in that article
which aroused your scorn, are invaluable to me
in practical work. Observation with me is second
nature. You appeared to be surprised when I told
you, on our first meeting, that you had come from
Afghanistan.”
“You were told, no doubt.”
“Nothing of the sort. I knew you came from
Afghanistan. From long habit the train of thoughts
ran so swiftly through my mind, that I arrived at
the conclusion without being conscious of interme-
diate steps. There were such steps, however. The
train of reasoning ran, ‘Here is a gentleman of a
medical type, but with the air of a military man.
Clearly an army doctor, then. He has just come
from the tropics, for his face is dark, and that is
not the natural tint of his skin, for his wrists are
fair. He has undergone hardship and sickness, as
his haggard face says clearly. His left arm has been
injured. He holds it in a stiff and unnatural man-
ner. Where in the tropics could an English army
doctor have seen much hardship and got his arm
wounded? Clearly in Afghanistan.’ The whole
train of thought did not occupy a second. I then
remarked that you came from Afghanistan, and
you were astonished.”
“It is simple enough as you explain it,” I said,
smiling. “You remind me of Edgar Allen Poe’s
Dupin. I had no idea that such individuals did
exist outside of stories.”
Sherlock Holmes rose and lit his pipe. “No
doubt you think that you are complimenting me in
comparing me to Dupin,” he observed. “Now, in
my opinion, Dupin was a very inferior fellow. That
trick of his of breaking in on his friends’ thoughts
with an apropos remark after a quarter of an hour’s
silence is really very showy and superficial. He had
some analytical genius, no doubt; but he was by
no means such a phenomenon as Poe appeared to
imagine.”
“Have you read Gaboriau’s works?” I asked.
“Does Lecoq come up to your idea of a detective?”
Sherlock Holmes sniffed sardonically. “Lecoq
was a miserable bungler,” he said, in an angry voice;
“he had only one thing to recommend him, and that
was his energy. That book made me positively ill.
The question was how to identify an unknown pris-
oner. I could have done it in twenty-four hours.
Lecoq took six months or so. It might be made
a text-book for detectives to teach them what to
avoid.”
I felt rather indignant at having two characters
whom I had admired treated in this cavalier style.
I walked over to the window, and stood looking
out into the busy street. “This fellow may be very
clever,” I said to myself, “but he is certainly very
conceited.”
“There are no crimes and no criminals in these
days,” he said, querulously. “What is the use of
having brains in our profession? I know well that I
have it in me to make my name famous. No man
lives or has ever lived who has brought the same
amount of study and of natural talent to the de-
tection of crime which I have done. And what is
the result? There is no crime to detect, or, at most,
some bungling villany with a motive so transparent
that even a Scotland Yard official can see through
it.”
I was still annoyed at his bumptious style of
conversation. I thought it best to change the topic.
“I wonder what that fellow is looking for?” I
asked, pointing to a stalwart, plainly-dressed in-
dividual who was walking slowly down the other
side of the street, looking anxiously at the numbers.
He had a large blue envelope in his hand, and was
evidently the bearer of a message.
“You mean the retired sergeant of Marines,”
said Sherlock Holmes.
“Brag and bounce!” thought I to myself. “He
knows that I cannot verify his guess.”
The thought had hardly passed through my
mind when the man whom we were watching
caught sight of the number on our door, and ran
rapidly across the roadway. We heard a loud knock,
a deep voice below, and heavy steps ascending the
stair.
“For Mr. Sherlock Holmes,” he said, stepping
into the room and handing my friend the letter.
Here was an opportunity of taking the conceit
out of him. He little thought of this when he made
that random shot. “May I ask, my lad,” I said, in
the blandest voice, “what your trade may be?”
“Commissionaire, sir,” he said, gruffly. “Uni-
form away for repairs.”
“And you were?” I asked, with a slightly mali-
cious glance at my companion.
“A sergeant, sir, Royal Marine Light Infantry,
sir. No answer? Right, sir.”
He clicked his heels together, raised his hand in
a salute, and was gone.
