The Sign of Four
| Chapter 2: The Statement of the Case
The Science of Deduction
Sherlock Holmes took his bottle from the corner of the mantelpiece, and his hypodermic syringe from its neat morocco case.
With his long, white, nervous fingers he adjusted the delicate
needle and rolled back his left shirtcuff. For some little time his
eyes rested thoughtfully upon the sinewy forearm and wrist, all
dotted and scarred with innumerable puncture-marks. Finally, he
thrust the sharp point home, pressed down the tiny piston, and
sank back into the velvet-lined armchair with a long sigh of
Three times a day for many months I had witnessed this
performance, but custom had not reconciled my mind to it. On
the contrary, from day to day I had become more irritable at the
sight, and my conscience swelled nightly within me at the thought
that I had lacked the courage to protest. Again and again I had
registered a vow that I should deliver my soul upon the subject;
but there was that in the cool, nonchalant air of my companion
which made him the last man with whom one would care to take
anything approaching to a liberty. His great powers, his masterly
manner, and the experience which I had had of his many extraordinary qualities, all made me diffident and backward in crossing
Yet upon that afternoon, whether it was the Beaune which I
had taken with my lunch or the additional exasperation produced
by the extreme deliberation of his manner, I suddenly felt that I
could hold out no longer.
"Which is it to-day," I asked, "morphine or cocaine?"
He raised his eyes languidly from the old black-letter volume
which he had opened.
"It is cocaine," he said, "a seven-per-cent solution. Would
you care to try it?"
"No, indeed," I answered brusquely. "My constitution has
not got over the Afghan campaign yet. I cannot afford to throw
any extra strain upon it."
He smiled at my vehemence. "Perhaps you are right, Watson," he said. "I suppose that its influence is physically a bad
one. I find it, however, so transcendently stimulating and clarifying to the mind that its secondary action is a matter of small
"But consider!" I said earnestly. "Count the cost! Your brain
may, as you say, be roused and excited, but it is a pathological
and morbid process which involves increased tissue-change and
may at least leave a permanent weakness. You know, too, what
a black reaction comes upon you. Surely the game is hardly
worth the candle. Why should you, for a mere passing pleasure,
risk the loss of those great powers with which you have been
endowed? Remember that I speak not only as one comrade to
another but as a medical man to one for whose constitution he is
to some extent answerable."
He did not seem offended. On the contrary, he put his fingertips together, and leaned his elbows on the arms of his chair, like
one who has a relish for conversation.
"My mind," he said, "rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram, or
the most intricate analysis, and I am in my own proper atmosphere. I can dispense then with artificial stimulants. But I abhor
the dull routine of existence. I crave for mental exaltation. That
is why I have chosen my own particular profession, or rather
created it, for I am the only one in the world."
"The only unofficial detective?" I said, raising my eyebrows.
"The only unofficial consulting detective," he answered. "I
am the last and highest court of appeal in detection. When Gregson, or Lestrade, or Athelney Jones are out of their depths —
which, by the way, is their normal state — the matter is laid
before me. I examine the data, as an expert, and pronounce a
specialist's opinion. I claim no credit in such cases. My name
figures in no newspaper. The work itself, the pleasure of finding
a field for my peculiar powers, is my highest reward. But you
have yourself had some experience of my methods of work in the
Jefferson Hope case."
"Yes, indeed," said I cordially. "I was never so struck by
anything in my life. I even embodied it in a small brochure, with
the somewhat fantastic title of 'A Study in Scarlet.' "
He shook his head sadly.
"I glanced over it," said he. "Honestly, I cannot congratulate
you upon it. Detection is, or ought to be, an exact science and
should be treated in the same cold and unemotional manner. You
have attempted to tinge it with romanticism, which produces
much the same effect as if you worked a love-story or an
elopement into the fifth proposition of Euclid."
"But the romance was there," I remonstrated. "I could not
tamper with the facts."
"Some facts should be suppressed, or, at least, a just sense of
proportion should be observed in treating them. The only point
in the case which deserved mention was the curious analytical
reasoning from effects to causes, by which I succeeded in unravelling it."
I was annoyed at this criticism of a work which had been
specially designed to please him. I confess, too, that I was
irritated by the egotism which seemed to demand that every line
of my pamphlet should be devoted to his own special doings.
More than once during the years that I had lived with him in
Baker Street I had observed that a small vanity underlay my
companion's quiet and didactic manner. I made no remark
however, but sat nursing my wounded leg. I had had a Jezaii
bullet through it some time before, and though it did not prevent
me from walking it ached wearily at every change of the weather.
"My practice has extended recently to the Continent," said
Holmes after a while, filling up his old brier-root pipe. "I was
consulted last week by Francois le Villard, who, as you
probably know, has come rather to the front lately in the French
detective service. He has all the Celtic power of quick intuition
but he is deficient in the wide range of exact knowledge which is
essential to the higher developments of his art. The case was
concerned with a will and possessed some features of interest. I
was able to refer him to two parallel cases, the one at Riga in
1857, and the other at St. Louis in 1871, which have suggested
to him the true solution. Here is the letter which I had this
morning acknowledging my assistance."
He tossed over, as he spoke, a crumpled sheet of foreign
notepaper. I glanced my eyes down it, catching a profusion of
notes of admiration, with stray magnifiques, coup-de-maitres and
tours-de-force, all testifying to the ardent admiration of the
"He speaks as a pupil to his master," said I.
"Oh, he rates my assistance too highly," said Sherlock Holmes
lightly. "He has considerable gifts himself. He possesses two
out of the three qualities necessary for the ideal detective. He has
the power of observation and that of deduction. He is only
wanting in knowledge, and that may come in time. He is now
translating my small works into French."
"Oh, didn't you know?" he cried, laughing. "Yes, I have
been guilty of several monographs. They are all upon technical
subjects. Here, for example, is one 'Upon the Distinction between the Ashes of the Various Tobaccos.' In it I enumerate a
hundred and forty forms of cigar, cigarette, and pipe tobacco,
with coloured plates illustrating the difference in the ash. It is a
point which is continually turning up in criminal trials, and
which is sometimes of supreme importance as a clue. If you can
say definitely, for example, that some murder had been done by
a man who was smoking an Indian lunkah, it obviously narrows
your field of search. To the trained eye there is as much difference between the black ash of a Trichinopoly and the white fluff
of bird's-eye as there is between a cabbage and a potato."
"You have an extraordinary genius for minutiae," I remarked.
"I appreciate their importance. Here is my monograph upon
the tracing of footsteps, with some remarks upon the uses of
plaster of Paris as a preserver of impresses. Here, too, is a
curious little work upon the influence of a trade upon the form of
the hand, with lithotypes of the hands of slaters, sailors, cork-cutters, compositors, weavers, and diamond-polishers. That is a
matter of great practical interest to the scientific detective —
especially in cases of unclaimed bodies, or in discovering the
antecedents of criminals. But I weary you with my hobby."
"Not at all," I answered earnestly. "It is of the greatest
interest to me, especially since I have had the opportunity of
observing your practical application of it. But you spoke just
now of observation and deduction. Surely the one to some extent
implies the other."
"Why, hardly," he answered, leaning back luxuriously in his
armchair and sending up thick blue wreaths from his pipe. "For
example, observation shows me that you have been to the Wigmore
Street Post-Office this morning, but deduction lets me know that
when there you dispatched a telegram."
"Right!" said I. "Right on both points! But I confess that I
don't see how you arrived at it. It was a sudden impulse upon
my part, and I have mentioned it to no one."
"It is simplicity itself," he remarked, chuckling at my
surprise — "so absurdly simple that an explanation is superfluous;
and yet it may serve to define the limits of observation and of
deduction. Observation tells me that you have a little reddish
mould adhering to your instep. Just opposite the Wigmore Street
Office they have taken up the pavement and thrown up some
earth, which lies in such a way that it is difficult to avoid
treading in it in entering. The earth is of this peculiar reddish tint
which is found, as far as I know, nowhere else in the neighbourhood. So much is observation. The rest is deduction."
"How, then, did you deduce the telegram?"
"Why, of course I knew that you had not written a letter,
since I sat opposite to you all morning. I see also in your open
desk there that you have a sheet of stamps and a thick bundle of
postcards. What could you go into the post-office for, then, but
to send a wire? Eliminate all other factors, and the one which
remains must be the truth."
"In this case it certainly is so," I replied after a little thought.
"The thing, however, is, as you say, of the simplest. Would you
think me impertinent if I were to put your theories to a more
"On the contrary," he answered, "it would prevent me from
taking a second dose of cocaine. I should be delighted to look
into any problem which you might submit to me."
"I have heard you say it is difficult for a man to have any
object in daily use without leaving the impress of his individuality upon it in such a way that a trained observer might read it.
Now, I have here a watch which has recently come into my
possession. Would you have the kindness to let me have an opinion
upon the character or habits of the late owner?"
I handed him over the watch with some slight feeling of
amusement in my heart, for the test was, as I thought, an
impossible one, and I intended it as a lesson against the somewhat dogmatic tone which he occasionally assumed. He balanced
the watch in his hand, gazed hard at the dial, opened the back,
and examined the works, first with his naked eyes and then with
a powerful convex lens. I could hardly keep from smiling at his
crestfallen face when he finally snapped the case to and handed it
"There are hardly any data," he remarked. "The watch has
been recently cleaned, which robs me of my most suggestive
"You are right," I answered. "It was cleaned before being
sent to me."
In my heart I accused my companion of putting forward a
most lame and impotent excuse to cover his failure. What data
could he expect from an uncleaned watch?
"Though unsatisfactory, my research has not been entirely
barren," he observed, staring up at the ceiling with dreamy,
lack-lustre eyes. "Subject to your correction, I should judge that
the watch belonged to your elder brother, who inherited it from
"That you gather, no doubt, from the H. W. upon the back?"
"Quite so. The W. suggests your own name. The date of the
watch is nearly fifty years back, and the initials are as old as the
watch: so it was made for the last generation. Jewellery usually
descends to the eldest son, and he is most likely to have the same
name as the father. Your father has, if I remember right, been
dead many years. It has, therefore, been in the hands of your
"Right, so far," said I. "Anything else?"
"He was a man of untidy habits — very untidy and careless.
He was left with good prospects, but he threw away his chances,
lived for some time in poverty with occasional short intervals of
prosperity, and finally, taking to drink, he died. That is all I can
I sprang from my chair and limped impatiently about the room
with considerable bitterness in my heart.
"This is unworthy of you, Holmes," I said. "I could not have
believed that you would have descended to this. You have made
inquiries into the history of my unhappy brother, and you now
pretend to deduce this knowledge in some fanciful way. You
cannot expect me to believe that you have read all this from his
old watch! It is unkind and, to speak plainly, has a touch of
charlatanism in it."
"My dear doctor," said he kindly, "pray accept my apologies. Viewing the matter as an abstract problem, I had forgotten
how personal and painful a thing it might be to you. I assure
you, however, that I never even knew that you had a brother
until you handed me the watch."
"Then how in the name of all that is wonderful did you get
these facts? They are absolutely correct in every particular."
"Ah, that is good luck. I could only say what was the balance
of probability. I did not at all expect to be so accurate."
"But it was not mere guesswork?"
"No, no: I never guess. It is a shocking habit — destructive to
the logical faculty. What seems strange to you is only so because
you do not follow my train of thought or observe the small facts
upon which large inferences may depend. For example, I began
by stating that your brother was careless. When you observe the
lower part of that watch-case you notice that it is not only dinted
in two places but it is cut and marked all over from the habit of
keeping other hard objects, such as coins or keys, in the same
pocket. Surely it is no great feat to assume that a man who treats
a fifty-guinea watch so cavalierly must be a careless man. Neither is it a very far-fetched inference that a man who inherits one
article of such value is pretty well provided for in other respects."
I nodded to show that I followed his reasoning.
"It is very customary for pawnbrokers in England, when they
take a watch, to scratch the numbers of the ticket with a pinpoint upon the inside of the case. It is more handy than a label as
there is no risk of the number being lost or transposed. There are
no less than four such numbers visible to my lens on the inside
of this case. Inference — that your brother was often at low water.
Secondary inference — that he had occasional bursts of prosperity, or he could not have redeemed the pledge. Finally, I ask you
to look at the inner plate, which contains the keyhole. Look at
the thousands of scratches all round the hole — marks where the
key has slipped. What sober man's key could have scored those
grooves? But you will never see a drunkard's watch without
them. He winds it at night, and he leaves these traces of his
unsteady hand. Where is the mystery in all this?"
"It is as clear as daylight," I answered. "I regret the injustice
which I did you. I should have had more faith in your marvellous
faculty. May I ask whether you have any professional inquiry on
foot at present?"
"None. Hence the cocaine. I cannot live without brainwork.
What else is there to live for? Stand at the window here. Was
ever such a dreary, dismal, unprofitable world? See how the
yellow fog swirls down the street and drifts across the duncoloured houses. What could be more hopelessly prosaic and
material? What is the use of having powers, Doctor, when one
has no field upon which to exert them? Crime is commonplace,
existence is commonplace, and no qualities save those which are
commonplace have any function upon earth."
I had opened my mouth to reply to this tirade when, with a
crisp knock, our landlady entered, bearing a card upon the brass
"A young lady for you, sir," she said, addressing my
"Miss Mary Morstan," he read. "Hum! I have no recollection of the name. Ask the young lady to step up, Mrs. Hudson.
Don't go, Doctor. I should prefer that you remain."
The Sign of Four
| Chapter 2: The Statement of the Case