Thorndyke Retraces the Trail
Apparently Thorndyke had seen me from the window as I crossed the
Walk, for, when I reached the landing, I found him standing in the
open doorway of his chambers; and at the sight of him, whatever traces
of unreasonable resentment may have lingered in my mind, melted away
instantly. He grasped my hand with almost affectionate warmth, and
looking at me earnestly and with the most kindly solicitude, said:
“I am glad you have come, Mayfield. I couldn’t bear to think of you
alone in your chambers, haunted by this horrible tragedy.”
“You have heard, then—about Barbara, I mean?”
“Yes. Miller called and told me. Of course, he is righteously angry
that she has escaped, and I sympathize with him. But for us—for you
and me—it is a great deliverance. I was profoundly relieved when I
heard that she was gone; that the axe had fallen once for all.”
“Yes,” I admitted, “it was better than the frightful alternative of a
trial and what would have followed. But still, it was terrible to see
her, lying dead, and to know that it was my hand—the hand of her
oldest and dearest friend—that had struck the blow.”
“It was my hand, Mayfield, not yours that actually struck the blow.
But even if it had been yours instead of your agent’s, what could have
been more just and proper than that retribution should have come
through the hand of the friend and guardian of that poor murdered
girl?”
I assented with a shudder to the truth of what he had said, but still
my mind was too confused to allow me to see things in their true
perspective. Barbara, my friend, was still more real to me than
Barbara the murdress. He nodded sympathetically enough when I
explained this, but rejoined, firmly:
“You must try, my dear fellow, to see things as they really are.
Shocking as this tragedy is, it would have been immeasurably worse if
that terrible woman had not received timely warning. As it is, the
horrible affair has run its course swiftly and is at an end. And do
not forget that if the axe has fallen on the guilty its menace has
been lifted from the innocent. Madeline Norris and Anthony Wallingford
will sleep in peace to-night, free from the spectre of suspicion that
has haunted them ever since Harold Monkhouse died. As to the woman
whose body you found this morning, she was a monster. She could not
have been permitted to live. Her very existence was a menace to the
lives of all who came into contact with her.”
Again, I could not but assent to his stern indictment and his
impartial statement of the facts.
“Very well, Mayfield,” said he. “Then try to put it to yourself that,
for you, the worst has happened and is done with. Try to put it away
as a thing that now belongs to the past and is, in so far as it is
possible, to be forgotten.”
“As far as is possible,” I repeated. “Yes, of course, you are quite
right, Thorndyke. But forgetfulness is not a thing which we can
command at will.”
“Very true,” he replied. “But yet we can control to a large extent the
direction of our thoughts. We can find interests and occupations. And,
speaking of occupations, let me show you some of Polton’s
productions.”
He rose, and putting a small table by the side of my chair, placed on
it one or two small copper plaques and a silver medallion which he had
taken from a drawer. The medallion was the self-portrait of Stella
which had lain dormant in the wax mould through all the years which
had passed since her death, and as I took it in my hand and gazed at
the beloved face, I found it beautiful beyond my expectations.
“It is a most charming little work,” I said, holding it so that the
lamp light fell most favourably on the relic, “I am infinitely obliged
to you, Thorndyke.”
“Don’t thank me,” said he. “The whole credit is due to Polton. Not
that he wants any thanks, for the work has yielded him hours of
perfect happiness. But here he is with the products of another kind of
work.”
As he spoke, Polton entered with a tray and began in his neat,
noiseless way, to lay the table. I don’t know how much he knew, but
when I caught his eye and his smile of greeting, it seemed to me that
friendliness and kindly sympathy exuded from every line of his quaint,
crinkly face. I thanked him for his skilful treatment of my treasures
and then, observing that he was apparently laying the table for
supper, would have excused myself. But Thorndyke would hear of no
excuses.
“My dear fellow,” said he, “you are the very picture of physical
exhaustion. I suspect that you have had practically no food to-day. A
meal will help you to begin to get back to the normal. And, in any
case, you mustn’t disappoint Polton, who has been expecting you to
supper and has probably made a special effort to do credit to the
establishment.”
I could only repeat my acknowledgments of Polton’s goodness (noting
that he certainly must have made a special effort, to judge by the
results which began to make themselves evident) and, conquering my
repugnance to the idea of eating, take my place at the table.
It is perhaps somewhat humiliating to reflect that our emotional
states, which we are apt to consider on a lofty spiritual plane, are
controlled by matters so grossly material as the mere contents of our
stomachs. But such is the degrading truth, as I now realized. For no
sooner had I commenced a reluctant attack on the products of Polton’s
efforts and drunk a glass of Burgundy—delicately warmed by that
versatile artist to the exact optimum temperature—than my mental and
physical unrest began to subside and allow a reasonable, normal
outlook to develop, with a corresponding bodily state. In effect, I
made quite a good meal and found myself listening with lively interest
to Thorndyke’s account of the technical processes involved in
converting my little plaster plaques and the wax mould into their
final states in copper and silver.
Nevertheless, in the intervals of conversation the unforgettable
events of the morning and the preceding night tended to creep back
into my consciousness; and now a question which I had hitherto hardly
considered began to clamour for an answer. Towards the end of the
meal, I put it into words. Apropos of nothing in our previous
conversation, I asked:
“How did you know, Thorndyke?” and as he looked up inquiringly, I
added: “I mean, how were you able to make so confident a guess, for,
of course, you couldn’t actually know?”
“When do you mean?” he asked.
“I mean that when you applied for a Home Office authority you must
have had something to go on beyond a mere guess.”
“Certainly I had,” he replied. “It was not a guess at all. It was a
certainty. When I made the application I was able to say that I had
positive knowledge that Stella Keene had been poisoned with arsenic.
The examination of the poor child’s body was not for my information. I
would have avoided it if that had been possible. But it was not. As
soon as my declaration was made, the exhumation became inevitable. The
Crown could not have prosecuted on a charge of poisoning without an
examination of the victim’s body.”
“But, Thorndyke,” I expostulated, “how could you have been certain—I
mean certain in a legal sense? Surely it could have been no more than
a matter of inference.”
“It was not,” he replied. “It was a matter of demonstrated fact. I
could have taken the case into court and proved the fact of arsenical
poisoning. But, of course, the jury would have demanded evidence from
an examination of the body, and quite properly, too. Every possible
corroboration should be obtained in a criminal trial.”
“Certainly,” I agreed. “But still I find your statement
incomprehensible. You speak of demonstrated fact. But what means of
demonstration had you? There was my diary. I take it that that was the
principal source of your information; in fact I can’t think of any
other. But the diary could only have yielded documentary evidence,
which is quite a different thing from demonstrated fact.”
“Quite,” he agreed. “The diary contributed handsomely to the train of
circumstantial evidence that I had constructed. But the
demonstration—the final, positive proof—came from another source. A
very curious and unexpected source.”
“I suppose,” said I, “as the case is finished and dealt with, there
would be no harm in my asking how you arrived at your conclusion?”
“Not at all,” he replied. “The whole investigation is a rather long
story, but I will give you a summary of it if you like.”
“Why a summary?” I objected. “I would rather have it in extenso if it
will not weary you to relate it.”
“It will be more likely to weary you,” he replied. “But if you are
equal to a lengthy exposition, let us take to our easy chairs and
combine bodily comfort with forensic discourse.”
We drew up the two arm-chairs before the hearth, and when Polton had
made up the fire and placed between us a small table furnished with a
decanter and glasses, Thorndyke began his exposition.
“This case is in some respects one of the most curious and interesting
that I have met with in the whole of my experience of medico-legal
practice. At the first glance, as I told you at the time, the problem
that it presented seemed hopelessly beyond solution. All the evidence
appeared to be in the past and utterly irrecoverable. The vital
questions were concerned with events that had passed unrecorded and of
which there seemed to be no possibility that they could ever be
disinterred from the oblivion in which they were buried. Looking back
now on the body of evidence that has gradually accumulated, I am
astonished at the way in which the apparently forgotten past has given
up its secrets, one after another, until it has carried its revelation
from surmise to probability and from probability at last to
incontestible proof.
“The inquiry divides itself into certain definite stages, each of
which added new matter to that which had gone before. We begin,
naturally, with the inquest on Harold Monkhouse, and we may consider
this in three aspects: the ascertained condition of the body; the
evidence of the witnesses; and the state of affairs disclosed by the
proceedings viewed as a whole.
“First, as to the body: there appeared to be no doubt that Monkhouse
died from arsenical poisoning, but there was no clear evidence as to
how the poison had been administered. It was assumed that it had been
taken in food or in medicine—that it had been swallowed—and no
alternative method of administration was suggested or considered. But
on studying the medical witnesses’ evidence, and comparing it with the
descriptions of the patient’s symptoms, I was disposed to doubt
whether the poison had actually been taken by the mouth at all.”
“Why,” I exclaimed, “how else could it have been taken?”
“There are quite a number of different ways in which poisonous doses
of arsenic can be taken. Finely powdered arsenic is readily absorbed
by the skin. There have been several deaths from the use of ‘violet
powder’ contaminated with arsenic, and clothing containing powdered
arsenic would produce poisonous effects. Then there are certain
arsenical gases—notably arsine, or arseniureted hydrogen—which are
intensely poisonous and which possibly account for a part of the
symptoms in poisoning from arsenical wall-papers. There seemed to me
to be some suggestion of arsenical gas in Monkhouse’s case, but it was
obviously not pure gas-poisoning. The impression conveyed to me was
that of a mixed poisoning; that the arsenic had been partly inhaled
and partly applied to the skin, but very little, if any, taken by the
mouth.”
“You are not forgetting that arsenic was actually found in the
stomach?”
“No. But the quantity was very minute; and a minute quantity is of no
significance. One of the many odd and misleading facts about arsenic
poisoning is that, in whatever way the drug is taken, a small quantity
is always found in the stomach and there are always some signs of
gastric irritation. The explanation seems to be that arsenic which has
got into the blood in any way—through the skin, the lungs or
otherwise—tends to be eliminated in part through the stomach. At any
rate, the fact is that the presence of minute quantities of arsenic in
the stomach affords no evidence that the poison was swallowed.”
“But,” I objected, “what of the Fowler’s Solution which was found in
the medicine?”
“Exactly,” said he. “That was the discrepancy that attracted my
attention. The assumption was that deceased had taken in his medicine
a quantity of Fowler’s Solution representing about a grain and a half
of arsenious acid. If that had been so we should have expected to find
a very appreciable quantity in the stomach: much more than was
actually found. The condition of the body did not agree with the dose
that was assumed to have been taken; and when one came to examine the
evidence of the various witnesses there was further room for doubt.
Two of them had noticed the medicine at the time when the Fowler’s
Solution had not been added; but no witness had noticed it after the
alleged change and before the death of deceased. The presence of the
Fowler’s Solution was not observed until several days after his death.
Taking all the facts together, there was a distinct suggestion that
the solution had been added to the medicine at some time after
Monkhouse’s death. But this suggestion tended to confirm my suspicion
that the poison had not been swallowed. For the discovery of the
Fowler’s Solution in the medicine would tend to divert inquiry—and
did, in fact, divert it—from any other method of administering the
poison.
“To finish with the depositions: not only was there a complete lack of
evidence even suggesting any one person as the probable delinquent;
there was not the faintest suggestion of any motive that one could
consider seriously. The paltry pecuniary motive applied to all the
parties and could not be entertained in respect of any of them. The
only person who could have had a motive was Barbara. She was a young,
attractive woman, married to an elderly, unattractive husband. If she
had been attached to another man, she would have had the strongest and
commonest of all motives. But there was nothing in the depositions to
hint at any other man; and since she was absent from home when the
poisoning occurred, she appeared to be outside the area of possible
suspicion.
“And now to look at the evidence as a whole: you remember Miller’s
comment. There was something queer about the case; something very
oddly elusive. At the first glance it seemed to bristle with
suspicious facts. But when those facts were scrutinized they meant
nothing. There were plenty of clues but they led nowhere. There was
Madeline Norris who prepared the victim’s food—an obvious suspect. But
then it appeared that the poison was in the medicine, not in the food.
There was Wallingford who actually had poison in his possession. But
it was the wrong poison. There was the bottle that had undoubtedly
contained arsenic. But it was nobody’s bottle. There was the bottle
that smelled of lavender and had red stains in it and was found in
Miss Norris’s possession; but it contained no arsenic. And so on.
“Now all this was very strange. The strongest suspicion was thrown on
a number of people collectively. But it failed every time to connect
itself with any one individually. I don’t know precisely what Miller
thought of it, but to me it conveyed the strong impression of a
scheme—of something arranged, and arranged with extraordinary skill
and ingenuity. I had the feeling that, behind all these confusing and
inconsistent appearances, was a something quite different, with which
they had no real connection; that all these apparent clues were a sort
of smoke-screen thrown up to conceal the actual mechanism of the
murder.
“What could the mechanism of the murder have been? That was what I
asked myself. And by whom could the arrangements have been made and
carried out? Here the question of motive became paramount. What motive
could be imagined? And who could have been affected by it? That seemed
to be the essential part of the problem, and the only one that offered
the possibility of investigation.
“Now, as I have said, the most obvious motive in cases of this kind is
that of getting rid of a husband or wife to make room for another. And
ignoring moral considerations, it is a perfectly rational motive; for
the murder of the unwanted spouse is the only possible means of
obtaining the desired release. The question was, could such a motive
have existed in the present case; and the answer was that, on
inspection, it appeared to be a possible motive, although there was no
evidence that it actually existed. But, assuming its possibility for
the sake of argument, who could have been affected by it? At once, one
saw that Madeline Norris was excluded. The death of Harold Monkhouse
did not affect her, in this respect, at all. There remained only
Barbara and Wallingford. To take the latter first: He was a young man,
and the wife was a young, attractive woman; he had lived in the same
house with her, appeared to be her social equal and was apparently on
terms of pleasant intimacy with her. If he had any warmer feelings
towards her, her husband’s existence formed an insuperable obstacle to
the realization of his wishes. There was no evidence that he had any
such feelings, but the possibility had to be borne in mind. And there
were the further facts that he evidently had some means of obtaining
poisons and that he had ample opportunities for administering them to
the deceased. All things considered, Wallingford appeared, prima
facie, to be the most likely person to have committed the murder.
“Now to take the case of Barbara. In the first place, there was the
possibility that she might have had some feeling towards Wallingford,
in which case she would probably have been acting in collusion with
him and her absence from home on each occasion when the poisoning took
place would have been part of the arrangement. But, excluding
Wallingford, and supposing her to be concerned with some other man,
did her absence from home absolutely exclude the possibility of her
being the poisoner? There were suggestions of skilful and ingenious
arrangements to create false appearances. Was it possible that those
arrangements included some method by which the poison could be
administered during her absence without the connivance or knowledge of
any other person?
“I pondered this question carefully by the light of all the details
disclosed at the inquest; and the conclusion that I reached was that,
given a certain amount of knowledge, skill and executive ability, the
thing was possible. But as soon as I had admitted the possibility, I
was impressed by the way in which the suggestion fitted in with the
known facts and served to explain them. For all the arranged
appearances pointed to the use of Fowler’s Solution, administered by
the mouth. But this could not possibly have been the method if the
poisoner were a hundred miles away. And as I have said, I was strongly
inclined to infer, from the patient’s symptoms and the condition of
the body, that the poison had not been administered by the mouth.
“But all this, as you will realize, was purely hypothetical. None of
the assumptions was supported by a particle of positive evidence. They
merely represented possibilities which I proposed to bear in mind in
the interpretation of any new evidence that might come into view.
“This brings us to the end of the first stage; the conclusions arrived
at by a careful study of the depositions. But following hard on the
inquest was your visit to me when you gave me the particulars of your
past life and your relations with Barbara and Monkhouse. Now your
little autobiographical sketch was extremely enlightening, and, as it
has turned out, of vital importance. In the first place, it made clear
to me that your relations with Barbara were much more intimate than I
had supposed. You were not merely friends of long standing; you were
virtually in the relation of brother and sister. But with this very
important difference: that you were not brother and sister. An adopted
brother is a possible husband; an adopted sister is a possible wife.
And when I considered your departure to Canada with the intention of
remaining there for life, and your unexpected return, I found that the
bare possibility that Barbara might wish to be released from her
marriage had acquired a certain measure of probability.
“But further; your narrative brought into view another person who had
died. And the death of that person presented a certain analogy with
the death of Monkhouse. For if Barbara had wished to be your wife,
both these persons stood immovably in the way of her wishes. Of course
there was no evidence that she had any such wish, and the death of
Stella was alleged to have been due to natural causes. Nevertheless,
the faint, hypothetical suggestions offered by these new facts were
strikingly similar to those offered by the previous facts.
“The next stage opened when I read your diary, especially the volume
written during the last year of Stella’s life. But now one came out of
the region of mere speculative hypothesis into that of very definite
suspicion. I had not read very far when, from your chance references
to the symptoms of Stella’s illness, I came to the decided conclusion
that, possibly mingled with the symptoms of real disease, were those
of more or less chronic arsenical poisoning. And what was even more
impressive, those symptoms seemed to be closely comparable with
Monkhouse’s symptoms, particularly in the suggestion of a mixed
poisoning partly due to minute doses of arsine. I need not go into
details, but you will remember that you make occasional references to
slight attacks of jaundice (which is very characteristic of arsine
poisoning) and to ‘eye-strain’ which the spectacles failed to relieve.
But redness, smarting and watering of the eyes is an almost constant
symptom of chronic arsenic poisoning. And there were various other
symptoms of a decidedly suspicious character to which you refer and
which I need not go into now.
“Then a careful study of the diary brought into view another very
impressive fact. There were considerable fluctuations in Stella’s
condition. Sometimes she appeared to be so far improving as to lead
you to some hopes of her actual recovery. Then there would be a rather
sudden change for the worse and she would lose more than she had
gained. Now, at this time Barbara had already become connected with
the political movement which periodically called her away from home
for periods varying from one to four weeks; and when I drew up a table
of the dates of her departures and returns, I found that the periods
included between them—that is the periods during which she was absent
from home—coincided most singularly with Stella’s relapses. The
coincidence was so complete that, when I had set the data out in a
pair of diagrams in the form of graphs, the resemblance of the two
diagrams was most striking. I will show you the diagrams presently.
“But there was something else that I was on the lookout for in the
diary, but it was only quite near the end that I found it. Quite
early, I learned that Stella was accustomed to read and work at night
by the light of a candle. But I could not discover what sort of candle
she used; whether it was an ordinary household candle or one of some
special kind. At last I came on the entry in which you describe the
making of the wax mould; and then I had the information that I had
been looking for. In that entry you mention that you began by lifting
the reflector off the candle, by which I learned that the receptacle
used was not an ordinary candlestick. Then you remark that the candle
was of ‘good hard wax’; by which I learned that it was not an ordinary
household candle—these being usually composed of a rather soft
paraffin wax. Apparently, it was a stearine candle such as is made for
use in candle-lamps.”
“But,” I expostulated, “how could it possibly matter what sort of
candle she used? The point seems to be quite irrelevant.”
“The point,” he replied, “was not only relevant; it was of crucial
importance. But I had better explain. When I was considering the
circumstances surrounding the poisoning of Monkhouse, I decided that
the probabilities pointed to Barbara as the poisoner. But she was a
hundred miles away when the poisoning occurred; hence the question
that I asked myself was this: Was there any method that was possible
and practicable in the existing circumstances by which Barbara could
have arranged that the poisoning could be effected during her absence?
And the answer was that there was such a method, but only one. The
food and the medicine were prepared and administered by those who were
on the spot. But the candles were supplied by Barbara and by her put
into the bedside candle-box before she went away. And they would
operate during her absence.”
“But,” I exclaimed, “do I understand you to suggest that it is
possible to administer poison by means of a candle?”
“Certainly,” he replied. “It is quite possible and quite practicable.
If a candle is charged with finely powdered arsenious acid—‘white
arsenic’—when that candle is burnt, the arsenious acid will be partly
vaporized and partly converted into arsine, or arseniureted hydrogen.
Most of the arsine will be burnt in the flame and reconverted into
arsenious acid, which will float in the air, as it condenses, in the
form of an almost invisible white cloud. The actual result will be
that the air in the neighbourhood of the candle will contain small
traces of arsine—which is an intensely poisonous gas—and considerable
quantities of arsenious acid, floating about in the form of infinitely
minute crystals. This impalpable dust will be breathed into the lungs
of any person near the candle and will settle on the skin, from which
it will be readily absorbed into the blood and produce all the
poisonous effects of arsenic.
“Now, in the case of Harold Monkhouse, not only was there a special
kind of candle, supplied by the suspected person, but, as I have told
you, the symptoms during life and the appearances of the dead body,
all seemed to me to point to some method of poisoning through the
lungs and skin rather than by way of the stomach, and also suggested a
mixed poisoning in which arsine played some part. So that the candle
was not only a possible medium of the poisoning; it was by far the
most probable.
“Hence, when I came to consider Stella’s illness and noted the strong
suggestion of arsenic poisoning; and when I noted the parallelism of
her illness with that of Monkhouse; I naturally kept a watchful eye
for a possible parallelism in the method of administering the poison.
And not only did I find that parallelism; but in that very entry, I
found strong confirmation of my suspicion that the candle was
poisoned. You will remember that you mention the circumstance that on
the night following the making of the wax mould you were quite
seriously unwell. Apparently you were suffering from a slight attack
of acute arsenical poisoning, due to your having inhaled some of the
fumes from the burning candle.”
“Yes, I remember that,” said I. “But what is puzzling me is how the
candles could have been obtained. Surely it is not possible to buy
arsenical candles?”
“No,” he replied, “it is not. But it is possible to buy a
candle-mould, with which it is quite easy to make them. Remember that,
not so very long ago, most country people used to make their own
candles, and the hinged moulds that they used are still by no means
rare. You will find specimens in most local museums and in curio shops
in country towns and you can often pick them up in farm-house sales.
And if you have a candle-mould, the making of arsenical candles is
quite a simple affair. Barbara, as we know, used to buy a particular
German brand of stearine candles. All that she had to do was to melt
the candles, put the separated wicks into the mould, stir some
finely-powdered white arsenic into the melted wax and pour it into the
mould. When the wax was cool, the mould would be opened and the
candles taken out—these hinged moulds usually made about six candles
at a time. Then it would be necessary to scrape off the seam left by
the mould and smooth the candles to make them look like those sold in
the shops.”
“It was a most diabolically ingenious scheme,” said I.
“It was,” he agreed. “The whole villainous plan was very completely
conceived and most efficiently carried out. But to return to our
argument. The discovery that Stella had used a special form of candle
left me in very little doubt that Barbara was the poisoner and that
poisoned candles had been the medium used in both crimes. For we were
now out of the region of mere hypothesis. We were dealing with genuine
circumstantial evidence. But that evidence was still much too largely
inferential to serve as the material for a prosecution. We still
needed some facts of a definite and tangible kind; and as soon as you
came back from your travels on the South-Eastern Circuit, fresh facts
began to accumulate. Passing over the proceedings of Wallingford and
his follower and the infernal machine—all of which were encouraging,
as offering corroboration, but of no immediate assistance—the first
really important accretion of evidence occurred in connection with our
visit to the empty house in Hilborough Square.”
“Ha!” I exclaimed. “Then you did find something significant, in spite
of your pessimistic tone at the time? I may say, Thorndyke, that I had
a feeling that you went to that house with the definite expectation of
finding some specific thing. Was I wrong?”
“No. You were quite right. I went there with the expectation of
finding one thing and a faint hope of finding another; and both the
expectation and the hope were justified by the event. My main purpose
in that expedition was to obtain samples of the wall-paper from
Monkhouse’s room, but I thought it just possible that the soot from
the bedroom chimneys might yield some information. And it did.
“To begin with the wall-paper: the condition of the room made it easy
to secure specimens. I tore off about a dozen pieces and wrote a
number on each, to correspond with numbers that I marked on a rough
sketch-plan of the room which I drew first. My expectation was that
if—as I believed—arsenical candles had been burnt in that room,
arsenic would have been deposited on all the walls, but in varying
amounts, proportionate to the distance of the wall from the candle.
The loose piece of paper on the wall by the bed was, of course, the
real touchstone of the case, for if there were no arsenic in it, the
theory of the arsenical candle would hardly be tenable. I therefore
took the extra precaution of writing a full description of its
position on the back of the piece and deposited it for greater safety
in my letter-case.
“As soon as I reached home that day I spread out the torn fragment on
the wide stage of a culture microscope and examined its outer surface
with a strong top light. And the very first glance settled the
question. The whole surface was spangled over with minute crystals,
many of them hardly a ten-thousandth of an inch in diameter, sparkling
in the strong light like diamonds and perfectly unmistakable; the
characteristic octahedral crystals of arsenious acid.
“But distinctive as they were, I took nothing for granted. Snipping
off a good-sized piece of the paper, I submitted it to the
Marsh-Berzelius test and got a very pronounced ‘arsenical mirror,’
which put the matter beyond any possible doubt or question. I may add
that I tested all the other pieces and got an arsenic reaction from
them all, varying, roughly, according to their distance from the table
on which the candle stood.
“Thus the existence of the arsenical candle was no longer a matter of
hypothesis or even of mere probability; it was virtually a
demonstrated fact. The next question was, who put the arsenic into the
candle? All the evidence, such as it was, pointed to Barbara. But
there was not enough of it. No single fact connected her quite
definitely with the candles, and it had to be admitted that they had
passed through other hands than hers and that the candle-box was
accessible to several people, especially during her absence. Clear
evidence, then, was required to associate her—or some one else—with
those poisoned candles, and I had just a faint hope that such evidence
might be forthcoming. This was how I reasoned:
“Here was a case of poisoning in which the poison was
self-administered and the actual poisoner was absent. Consequently it
was impossible to give a calculated dose on a given occasion, nor was
it possible to estimate in advance the amount that would be necessary
to produce the desired result. Since the poison was to be left within
reach of the victim, to be taken from time to time, it would be
necessary to leave a quantity considerably in excess of the amount
actually required to produce death on any one occasion. It is probable
that all the candles in the box were poisoned. In any case, most of
them must have been; and as the box was filled to last for the whole
intended time of Barbara’s absence, there would be a remainder of
poisoned candles in the box when Monkhouse died. But the incident of
the ‘faked’ medicine showed that the poisoner was fully alive to the
possibility of an examination of the room. It was not likely that so
cautious a criminal would leave such damning evidence as the arsenical
candles in full view. For if, by chance, one of them had been lighted
and the bearer had developed symptoms of poisoning, the murder would
almost certainly have been out. In any case, we could assume that the
poisoner would remove them and destroy them after putting ordinary
candles in their place.
“But a candle is not a very easy thing to destroy. You can’t throw it
down a sink, or smash it up and cast it into the rubbish-bin. It must
be burnt; and owing to its inflammability, it must be burnt carefully
and rather slowly; and if it contains a big charge of arsenic, the
operator must take considerable precautions. And finally, these
particular candles had to be burnt secretly.
“Having regard to these considerations, I decided that the only safe
and practicable way to get rid of them was to burn them in a fireplace
with the window wide open. This would have to be done at night when
all the household was asleep, so as to be safe from interruption and
discovery; and a screen would have to be put before the fireplace to
prevent the glare from being visible through the open window. If there
were a fire in the grate, so much the better. The candles could be cut
up into small pieces and thrown into the fire one at a time.
“Of course the whole matter was speculative. There might have been no
surplus candles, or if there were, they might have been taken out of
the house and disposed of in some other way. But one could only act on
the obvious probabilities and examine the chimneys, remembering that
whereas a negative result would prove nothing for or against any
particular person, a positive result would furnish very weighty
evidence. Accordingly I collected samples of soot from the various
bedroom chimneys and from that of Barbara’s boudoir, labelling each of
them with the aid of the cards which you had left in the respective
rooms.
“The results were, I think, quite conclusive. When I submitted the
samples to analysis I found them all practically free from
arsenic—disregarding the minute traces that one expects to find in
ordinary soot—with one exception. The soot from Barbara’s bedroom
chimney yielded, not mere traces, but an easily measurable
quantity—much too large to have been attributable to the coal burnt in
the grate.
“Thus, you see, so far as the murder of Monkhouse was concerned, there
was a fairly conclusive case against Barbara. It left not a shadow of
doubt in my mind that she was the guilty person. But you will also see
that it was not a satisfactory case to take into court. The whole of
the evidence was scientific and might have appeared rather
unconvincing to the ordinary juryman, though it would have been
convincing enough to the judge. I debated with myself whether I should
communicate my discoveries to the police and leave them to decide for
or against a prosecution, or whether I should keep silence and seek
for further evidence. And finally I decided, for the present, to keep
my own counsel. You will understand why.”
“Yes,” said I. “You suspected that Stella, too, had been poisoned.”
“Exactly. I had very little doubt of it. And you notice that in this
case there was available evidence of a kind that would be quite
convincing to a jury—evidence obtainable from an examination of the
victim’s body. But here again I was disposed to adopt a waiting policy
for three reasons. First, I should have liked to avoid the exhumation
if possible. Second, if the exhumation were unavoidable, I was
unwilling to apply for it until I was certain that arsenic would be
found in the body; and third, although the proof that Stella had been
poisoned would have strengthened the case enormously against Barbara,
it would yet have added nothing to the evidence that a poisoned candle
had been used.
“But the proof of the poisoned candle was the kernel of the case
against Barbara. If I could prove that Stella had been poisoned by
means of a candle, that would render the evidence absolutely
irresistible. This I was not at present able to do. But I had some
slight hopes that the deficiency might be made up; that some new facts
might come into view if I waited. And, as there was nothing that
called for immediate action, I decided to wait, and in due course, the
deficiency was made up and the new facts did come into view.”
As he paused, I picked up Stella’s medallion and looked at it with a
new and sombre interest. Holding it up before him, I said:
“I am assuming, Thorndyke, that the new facts were in some way
connected with this. Am I right?”
“Yes,” he replied, “you are entirely right. The connection between
that charming little work and the evidence that sent that monster of
wickedness to her death is one of the strangest and most impressive
circumstances that has become known to me in the whole of my
experience. It is no exaggeration to say that when you and Stella were
working on that medallion, you were forging the last link in the chain
of evidence that could have dragged the murdress to the gallows.”
He paused, and, having replenished my glass, took the medallion in his
hand and looked at it thoughtfully. Then he knocked out and refilled
his pipe and I waited expectantly for the completion of this singular
story.