The Science of Sherlock Holmes: From Baskerville Hall to the Valley of Fear, the Real Forensics Behind the Great Detective's Greatest Cases

by E. J. Wagner

  Eventually, public opinion roused on behalf of Dreyfus, and he was retried. Incredibly, he was once again found guilty. Riots ensued. Proof that French Intelligence had manufactured evidence against Dreyfus was found. Officially, Dreyfus was “pardoned.” The guilty verdict against him was finally overturned in 1906.

  Bertillon’s reputation was tarnished, and the public’s trust in document examination was severely shaken. It would take the genius of Edmond Locard to change things.

  During World War I, in the year 1917, citizens of the French city of Tulle began receiving nasty anonymous letters. The recipients found themselves accused of a variety of repellent acts, usually of an interesting sexual nature. Women were informed that their husbands away at war were unfaithful; men from Tulle who were in the service got mail accusing their wives of general debauchery.

  The letters and their envelopes were subjected to the sort of scrutiny that Holmes applied in “The Man with the Twisted Lip” (“The envelope was a very coarse one and was stamped with the Gravesend postmark and with the date of that very day, or rather of the day before, for it was considerably after midnight. ‘Coarse writing,’ murmured Holmes”), but it didn’t solve the case. The first letters had been mailed, but when the post office was placed under surveillance, the letters began to be surreptitiously delivered by hand. Everyone was suspected, but no one was caught.

  Söderman, writing of the case, tells us that a priest, walking down the street, found a letter tucked into the door of the apothecary. Thinking it might be important, he retrieved it and brought it inside. Waving aside a thank-you drink, he insisted that the apothecary read it first, as it might be important news. The apothecary did so, then, with a cry of anguish, leaped upon the priest, clearly intent on doing bodily harm. The two were separated by neighbors who heard the sounds of fierce battle amid the breaking of medicine bottles. It seems the letter had accused the innocent priest of sleeping with the apothecary’s wife. Less amusing was the plight of a man who grew so depressed after receiving a letter that he had to be placed in an asylum, where he eventually died.

  The letters continued throughout the war, into the early twenties, poisoning the atmosphere. Finally, a clue emerged. A young woman of sterling reputation and strong religious principles, Angèle Laval, was heard discussing the contents of a letter before it had been received. Suspicion focused on her, but proof was needed. Dr. Locard was asked to consult. Locard perused over three hundred of the anonymous letters, as well as samples of Angèle Laval’s writing and those of her mother, since the two women lived together.

  The suspect missives were printed in block characters, so Locard needed to see similar specimens written by the Lavals. To obtain these he dictated to Angèle for most of a day, removing the samples as she finished them. At intervals she had hysterics. It was soon obvious that the writing was hers in most cases. Even though she tried to disguise her penmanship, she couldn’t remember from hour to hour what she had improvised, and a distinctive Y soon made an appearance. In similar fashion, Locard established that the other letters had been written by Angèle’s mother. Knowing that arrest was near, the two women decided on suicide by drowning and jumped into a reservoir. The elder died instantly. Angèle was fished out by passersby and stood trial. She was sentenced to only two months in prison and fined 500 francs.

  Commenting on the prisoner’s vaunted piety, Locard remarked, “Il n’y a rien plus sale que le rêve d’un saint” (There is nothing dirtier than the dream of a saint).

  By the end of the nineteenth century, the poison pen was often replaced by a machine. But if malefactors thought this would serve to disguise their handiwork, they were disappointed. In 1891, when “A Case of Identity” was published, Conan Doyle has Holmes note:

  “It is a curious thing … that a typewriter has really quite as much individuality as a man’s handwriting. Unless they are quite new, no two of them write exactly alike. Some letters get more worn than others, and some wear only on one side.”

  This was an exceedingly clever, if not entirely accurate, observation. Typewriters that used both lowercases and uppercases were not in common use until 1878, and their usefulness as evidence was not yet established when “Identity” was written. As it happens, typewriters, even when spanking new, showed enough individual quirks to firmly establish identity. Locard, devoted admirer of the Great Detective that he was, managed to prove the point.

  Poisonous letters began to appear in the city of Lyon nailed to the doorways of houses. They drew so much attention that the Sûreté was asked to investigate. Some of the letters were typed, others constructed of letters cut from newspapers. Locard—reasoning as Holmes did in A Study in Scarlet that if a man writes on a wall or pins something there, he instinctively does it at eye level—focused his inquiries on a father and son who were of appropriate height and who had access to typewriters. One of the typewriters in the father’s office was identified as the one used in constructing the obscene posted letters. Fingerprints discovered on one of the letters provided additional evidence.

  The crime, committed by parent and offspring with no clear motive, was very similar to the case in Tulle. The penalty was precisely the same—two months in prison and a fine of 500 francs. (As Holmes observed in A Study in Scarlet, “There is nothing new under the sun. It has all been done before.”)

  The storytelling skills of Conan Doyle sparked the imagination of scientists and provided a great contribution by making the public aware of the function of police laboratories. But when it came to handwriting, or chirography, as it was called in the nineteenth century, Sherlock Holmes was sometimes a bit overly enthusiastic. In spite of popular belief, even a highly trained forensic document examiner cannot reliably tell handedness, gender, or age from handwriting. The additional claim, largely made by graphologists, that psychological traits can be deciphered from handwriting has no basis in empirical evidence. Like astrology, it belongs to the realm of pseudoscience.

  Scientifically oriented forensic document examiners test ink, paper, styles of writing, and impressions made on written material. They photograph and enlarge specimens so that they can observe tiny discrepancies. They are wisely cautious in drawing conclusions.

  Consider the embarrassment of the graphologists asked to examine the doodles found on British prime minister Tony Blair’s desk at the Davos World Economic Forum. As Reuters gleefully reported in January 2005, the “handwriting experts” concluded that Mr. Blair was “struggling to concentrate, … stressed and tense,” and, most damning, “not a natural leader.” It was later discovered that the doodles were not the work of Mr. Blair but of Bill Gates, the founder of Microsoft, who had shared a table with the prime minister at the summit.

  As Mr. Holmes once remarked in “The Adventure of the Six Napoleons,” “The Press, Watson, is a most valuable institution, if you only know how to use it.”

  Whatever remains

  • In 1910, Albert S. Osborn published his reference work on the examination and identification of handwriting. It became the unofficial bible of the subject in the United States.

  • In 1935, at the trial of Bruno Richard Hauptmann for the kidnapping and murder of the infant son of Colonel Charles A. Lindbergh, Osborn’s testimony on the ransom notes proved devastating for the defense.

  • In 1945, the mutilated body of a woman named Frances Brown was found on her bed. Scrawled in lipstick on the wall above the corpse were the words “For God’s sake catch me before I kill more, I cannot control myself.” A student named William Heirens was arrested for the murder. He confessed to the killing of Brown as well as to other homicides. The writing on the wall was compared to Heirens’s usual hand and considered in terms of the height of the suspect, just as Holmes and Locard would have suggested. It was believed to be corroborative evidence. Heirens, still in prison, now insists that his confession was coerced and that the handwriting experts were mistaken.

  • In the 1950 trial of accused traitor Alger Hiss for perjury, the
American elder statesman was found guilty largely on evidence given by document experts who testified that the stolen papers were typed on an old Woodstock typewriter belonging to Hiss. The e’s and g’s on the machine were said to be distinctive by FBI laboratory examiner Ramos Feehan.

  CHAPTER 12

  A Voice in the Blood

  “Let us have some fresh blood.” —Sherlock Holmes in A Study in Scarlet

  Sherlock holmes’s passion for science and his innovative intellect are displayed with striking clarity as he announces his development of a chemical test for hemoglobin. Watson describes this amazing event in the 1887 A Study in Scarlet:

  Broad, low tables were scattered about, which bristled with retorts, test-tubes, and little Bunsen lamps, with their blue flickering flames. There was only one student in the room, who was bending over a distant table absorbed in his work. At the sound of our steps he glanced round and sprang to his feet with a cry of pleasure. “I’ve found it! I’ve found it,” he shouted to my companion, running towards us with a test-tube in his hand. “I have found a reagent which is precipitated by hemoglobin, and by nothing

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  else.” Had he discovered a gold mine, greater delight could not have shone upon his features… .

  “Why, man, [said Holmes,] it is the most practical medicolegal discovery for years. Don’t you see that it gives us an infallible test for blood stains?”

  Holmes was understandably elated. Determining whether a stain was truly blood was an old and difficult problem in criminal investigation. All sorts of attempts had been made to establish a reliable test. In France in the early nineteenth century, Ambrose Tardieu had even experimented with an olfactory method, but although a number of blindfolded volunteers had sniffed diligently at various sanguinary specimens, the results were too erratic to be of use.

  Blood is a marvelously changeable fluid. When fresh it is usually frankly red, but its odor as well as its appearance may be modified by a number of things, including the kind of material on which it has fallen. Blood on a polished metal surface glistens, for instance, while on soft fabric it is usually absorbed quickly and takes on a stiffened aspect. The color can change rapidly, from red to brown to gray-green. If attempts to remove the stain have been made by the use of water or chemicals, the color will be affected and the stain may not be easily visible. Blood is often adulterated by other bodily fluids or contaminated by poison, which may also affect its appearance. Some foods, such as garlic, affect its odor. Even a meticulous Sherlockian examination of suspicious stains with a magnifying glass is not sufficient to definitely identify blood.

  Medical jurisprudence addressed the problem in three basic ways. Sherlock Holmes is aware of two of them, as he makes clear when he says, “The old guaiacum test was very clumsy and uncertain. So is the microscopic examination for blood corpuscles. The latter is valueless if the stains are a few hours old.”

  The guaiacum test, which Holmes disdains, was based on the fact that the resin of the West Indian guaiacum tree turns the deep blue color of sapphires when oxidized. This change in color will result as well if a mixture of blood and hydrogen peroxide is added to the guaiacum. The difficulty with this test lies in the fact that a number of substances besides blood may produce positive results, including bile, saliva, and red wine. As wine would take several hours longer than blood to achieve the blue color, a careful operator could distinguish it from blood. Still, the existence of blood was not directly established by the guaiacum test, but the presence of hemoglobin was inferred by a positive result. There were a number of other chemical tests in use at the time, but they were no more conclusive.

  The microscopic test for blood was also, as Holmes said, by itself of limited value. Charles Meymott Tidy described the laborious process in 1882, advising the experimenter to cut out a small portion of the stained fabric and place it on a microscope glass and then moisten it with an appropriate solution before covering it with a coverslip. He warns against using water, which will cause the corpuscles to swell. (Tidy lists chloral hydrate solution along with a few other choices as adequate.)

  The slide, he says, should then be examined with a 1⁄4-inch power and the corpuscles measured with a micrometer. “All structures associated with a blood stain should be examined with great care,” he continues, explaining that if hair, biliary or fecal matter, spermatozoa, epithelial cells, or brain tissue are found mixed with the sample, they may help in determining the origin of the stain. Charts were available that listed, more or less accurately, the size and shape of corpuscles in a variety of creatures. Researchers were expected to compare the cells under their microscope with the chart to attempt to identify the source. The problem lay in the wide range of possibilities. Tidy writes:

  The blood-corpuscles in man and in all mammalia (excepting the camel tribe) are circular, flattened, transparent, non-nucleated cells presenting (as generally seen) concave sides with a central bright spot. This bright spot, however, by a small change of focus or of light may be made to appear shaded.

  The diameter of the blood-corpuscles in a man varies from 1-2800th of an inch to 1-4000th.

  These corpuscles vary in size and shape in different animals.

  It was a very complex system, and when the cells were dehydrated, they lost their shape, making identification even more difficult. And dried bloodstains were often precisely the issue in criminal cases, as Holmes informs Watson:

  “Criminal cases are continually hinging upon that one point. A man is suspected of a crime months perhaps after it has been committed. His linen or clothes are examined and brownish stains discovered upon them. Are they blood stains, or mud stains, or rust stains, or fruit stains, or what are they? That is a question which has puzzled many an expert, and why? Because there was no reliable test. Now we have the Sherlock Holmes’s test, and there will no longer be any difficulty.”

  His eyes fairly glittered as he spoke, and he put his hand over his heart and bowed as if to some applauding crowd conjured up by his imagination.

  Alas, the Great Detective overstates the case. In 1887, when Holmes made this claim in A Study in Scarlet, there was already one very reliable test in use for the presence of blood, which he left unmentioned—spectrum analysis. Dr. Tidy, in his text, tells us that this method was used by Henry Letheby, professor of chemistry at London Hospital, as early as 1864, in the celebrated murder trial of Franz Müller.

  On July 9 of that year at a quarter after ten in the evening, two bank clerks boarded an empty first-class train compartment at the Hackney station of the North London line. One of the pair casually placed his hand on the seat, only to feel it was coated with an upsettingly sticky substance. In the dim light of the oil lamps, he could just make out its red color. The guard was called before the train started and the car was searched. What appeared to be more blood was found on the cushions, the window, one of the door handles, and a walking stick. A small black bag and a black beaver hat stamped with the maker’s name, J. H. Walker, completed the scene. If the sticky red fluid was really blood, what and where was its source?

  There were no witnesses to what might have occurred in the carriage. In those days, there was no corridor connecting railway cars and there were no windows between them. Robberies, some of them violent, were not infrequent, particularly at night. Suspecting this was a similar event, the police ordered the car locked, detached, and sent first to Chalk Farm and then to Bow Station for further examination. The hat, stick, bag, and cushions were given to the Metropolitan Police so that the stains could be tested and identified as blood if possible.

  At roughly the same time that the carriage was being searched, the driver of a train going in the opposite direction saw a figure slumped on a six-foot-wide stretch of ground that ran along the tracks between Hackney Wick and Bow Stations. Stopping the train, the driver got out and discovered an unconscious man who had obviously been severely beaten. Taken to a nearby public house, he was identified by the contents of his pockets as Thomas Briggs
, the seventy-year-old head clerk at the banking house of Robarts on Lombard Street. Mr. Briggs had a fractured skull, among other injuries, and died the following morning without regaining consciousness. His distraught son, summoned by the police, identified the bag and walking stick as belonging to his father but said he had never before seen the hat found in the carriage. A top hat, which Mr. Briggs had worn to the train, was missing, and so were his gold watch and chain.

  Inspector Dick Tanner reasoned that the crime was an unplanned robbery and that the assailant had, in the stress of the moment, taken the wrong hat away with him. He put out a description of the hat left behind as well as of the watch and chain. As the attack on Mr. Briggs was the first known homicide in an English railway car, the resultant publicity was enormous. It was quickly rewarded when a jeweler, with the singularly appropriate name of Death (disappointingly, it is pronounced “Deeth”), came forward with the missing jewelry and explained that a customer had exchanged them for a similar set of the same value.

  Hearing of this, a cab driver named Matthews told the police that a family friend named Franz Müller had given Matthew’s tenyear-old daughter a jewel box to play with that bore the label “Death,” and that Müller owned a beaver hat made by J. H. Walker. A photograph of Müller was given to the police by Matthews, and Death identified it as that of his customer.

  But Müller was gone. Inspector Tanner questioned Müller’s landlady and was told he had left for New York on the sailing ship Victoria. Foreshadowing Inspector Dew’s efforts forty-five years later in the Crippen case, Tanner boarded the steamship City of Manchester and arrived in New York weeks before the arrival of the Victoria. Müller was apprehended still in possession of Mr. Briggs’s hat, which had been cut down to allow the removal of Briggs’s name. The suspect was promptly extradited and returned to England to stand trial at the Old Bailey on October 27.