The American legal writers Francis Wharton and Moreton Stille cited a case in Norwich, England, in which a little girl was found dead in a field, her throat cut.8 The mother seemed strangely calm about the killing, so police detained her for questioning. She claimed she had gotten separated from her child while looking for flowers and denied any knowledge of how the girl died. Police found a long knife in her possession with a few tiny hairs adhering to its handle. She said the hairs had come from a rabbit she had slaughtered for dinner. A microscopist identified the hairs as those from a squirrel. The child had been wearing a squirrel-fur scarf, and the fibers from the scarf matched those on the knife. Faced with the evidence, the mother confessed.
Other clues came to light by examining dust, which not even the most scrupulous of criminals could remove. Dust—collected in the lining of a pocket, the weave of a coat, the groove of a pocketknife—could reveal where the suspect had been or what he or she did for a living. Gross cited the case of a jacket abandoned at a crime scene.9 It contained no overt clue as to its owner’s identity, but investigators put the coat in a heavy paper bag and beat it with sticks, then collected and analyzed the dust. It consisted largely of sawdust, which led to the preliminary deduction that the suspect was a carpenter or worked in a sawmill. But they also found gelatin and powdered glue, which carpenters did not widely use at the time. “The further deduction was drawn that the garment belonged to a joiner,” wrote Gross, a fact that eventually was substantiated.
A combination of microscopic and chemical techniques helped investigators identify bloodstains. Dried blood could resemble many different substances, such as rust, spores, chewing tobacco, paint, or vegetable matter. In order to distinguish blood from the other substances, experts made use of chemical tests, most notably one developed by the Dutch scientist J. Izaak Van Deen.10 To a suspected blood sample, the examiner would add tincture of guaiac, a resin derived from the bark of a tropical tree, and then add hydrogen peroxide. If the sample was blood, the chemicals would react with the hemoglobin of red blood cells and within seconds turn sapphire blue. For a more sensitive diagnosis, they could use a spectroscope, as Lacassagne did in the Badoil case.
Frequently when police found a suspect with bloody clothing or hands, especially in the countryside, he or she would claim to have recently slaughtered an animal. So it became important to distinguish human blood from that of animals, which they did by having an expert microscopically examine the size and shape of the red cells. The cells of no two species are identical: Birds, fish, and reptiles have oblong red corpuscles, with noticeable nuclei; mammalian cells are disk-shaped, with a depression in the center and no apparent nuclei. Among mammals, blood cells vary according to size, although not in relation to the size of the creature: A mouse’s red cells are larger than a lion’s, while a human’s are larger than those of an ox or a horse. George Gulliver, a British surgeon who spent decades examining the blood cells of some six hundred species, wrote that humans had the largest red cells, at 1/3200 of an inch, followed closely by dogs, at 1/3395 of an inch.11 The size difference seemed minuscule but was easily detected with the calibrated microscopes of the day. After the turn of the century, the German scientist Paul Uhlenhuth developed a fast, simple test for human blood based on antibody reactions, a method that is used to this day.
Experts learned to analyze blood patterns, as well. They learned to look for blood in unlikely places, such as the underside of tables, where it might have splashed up following an assault at floor level. Candlelight revealed blood on dark cloth more effectively than daylight. Patterns had meaning. Smear marks meant the body had been dragged, which argued against a finding of suicide. Blood droplets falling from a height of several feet made a larger splash pattern than those falling from only a few inches. Those falling straight down produced a round splatter, while those falling from a body in motion produced an oblong splash, with the narrower part of the drop indicating the direction.
Traces of sperm were also left at many crime scenes. In general, semen stains had irregular shapes and a sheen produced by the dried albumin. When soaked, they gave off a characteristic starchy smell. That provided a rough identification, but the only way to identify the residue positively was to microscopically identify individual spermatozoa, with their pear-shaped heads and long, whippy tails. Most examiners considered this process relatively simple, provided they viewed the entire sperm and not a collection of separated parts. It was too easy to mistake miscellaneous granules in the liquid for detached sperm heads or to mistake microscopic filaments for tails.
When the victim or his clothing had been washed, finding unbroken sperm could become almost impossible. “I … myself spent three weeks in isolating a few complete spermatozoa in a case of rape of a four-year-old child,” wrote Dr. Albert Florence, a colleague of Lacassagne at the Institute of Legal Medicine.12 Lacassagne had similar experiences, and he challenged Florence to come up with a sperm test that was as simple, fast, and reliable as the Van Deen test for blood. Florence threw himself at the problem and presented a study that was as broad as it was deep. In a series of papers, he surveyed the history of human knowledge about sperm (it wasn’t until 1824 that scientists discovered that the unity of sperm and egg creates life) and gave a thorough description of sperm—its structure, its chemistry, and the various stains that made it more visible under the microscope. Then he searched for simple chemical tests, experimenting with one reagent after another that would react exclusively to semen. Eventually, he found that if he prepared a solution of one part potassium and three parts iodine (potassium triiodide), chilled it, and added it to semen, dramatic brownish red crystals appeared.
He felt he had found the holy grail of testing for sex crimes. It was “incontestably the procedure of choice, to which it is necessary to have recourse in all difficult cases,” he wrote.13 Unfortunately, a couple of years later a German scientist found that when he added the solution to other substances that contained decomposed albumin, such as rotten egg whites, the rhomboid crystals also appeared. Still, nothing produced crystals faster or in greater profusion than seminal fluid, and so Florence’s solution remained a valuable preliminary test until a better one replaced it in the mid-1940s.
Footprints left important clues to a criminal’s identity, especially in an era when shoes were custom-made.14 The nail patterns of no two shoes were identical, so researchers developed a variety of ways to capture footprints in the soil by using gels or plaster of Paris, or even in snow (salts created an ice layer around the impression, which allowed a mold to be taken). A surprising number of murderers went barefoot.15 The shape of the foot, the height of the arch, and irregularities in the soles produced a positive identity. “There is a physiognomy of the foot just as there is of the face,” wrote Lacassagne’s colleagues Coutagne and Florence.16 Lacassagne instructed that in addition to making molds of footprints in soil, one could duplicate them with a pantograph, an instrument consisting of a framework of parallelograms that made it possible to trace objects and documents. He also developed a process to make invisible prints of bare feet on a hard floor come into view. He would soak the suspect area in silver nitrate (the same chemical used on photographic plates) and leave it for several days in the light. During that time, the salt in sweat left behind by the foot would react with the chemical and a print would appear.
The interpretation of footprints became quite a subtle art. Investigators used it to determine the height, stature, and emotional state of people at the crime scene (for example, excited people tend to walk faster and take longer strides). Gross noted that a deeper footprint did not necessarily indicate obesity: In normal firm soil, an increase of twenty kilograms in body weight made no difference in depth. But he asserted that obese people tended to walk with their toes pointed outward. One German specialist maintained that an outward-pointed gait indicated a “man of distinction,” in contrast to a man of the people, although French researchers disagreed.17
Fingerprints wou
ld not become common in police work until the first decade of the twentieth century, although their characteristics were being studied in England, India, and Argentina. Bertillon started attaching fingerprints to his anthropomorphic cards, although his method of classifying the cards did not change. He also worked increasingly with photography. He developed a technique called “metric photography,” whereby he mounted the camera on a large enough tripod to look down on the crime scene and circumscribed the area with measuring tape.18 Later, he developed metered frames, in which he could insert crime-scene photographs. This, he felt, got beyond the common problem that “the eye sees only what is already in the mind.”19
In considering the variety of methods Lacassagne and his colleagues employed, it is impossible not to compare them to a fictional detective whose career ran contemporaneously to theirs. Arthur Conan Doyle wrote the first novel featuring Sherlock Holmes, A Study in Scarlet, in 1887 and sustained the character over a period of forty years—despite the author’s attempt to kill him off at Reichenbach Falls in 1893, the same year that Hans Gross’s book was published. Real-life investigators found the character fascinating. Lacassagne’s disciple Edmond Locard said what in part motivated his career choice, aside from his mentor, was the Sherlock Holmes stories. Doyle’s own inspiration came from Dr. Joseph Bell, his medical instructor at the University of Edinburgh, whose powers as a medical diagnostician translated into those of an amateur detective; in addition, he took note of contemporary experts. In more than one instance, Holmes speaks about the work of Alphonse Bertillon. In the short story “The Adventure of the Naval Treaty,” Watson records a discussion with Holmes: “His conversation, I remember, was about the Bertillon system of measurements, and he expressed his enthusiastic admiration of the French savant.”20 In The Hound of the Baskervilles, Watson reports the following exchange between a client and Holmes:
“Recognizing, as I do, that you are the second highest expert in Europe—”21
“Indeed, sir! May I inquire who has the honor of being first?” asked Holmes, with some asperity.
“To the man of precisely scientific mind the work of Monsieur Alphonse Bertillon must always appeal strongly.”
“Then had you not better consult him?”
“I said, sir, to the precisely scientific mind. But as a practical man of affairs it is acknowledged that you stand alone. I trust, sir, that I have not inadvertently—”
“Just a little,” said Holmes.
Lacassagne admired the work of Conan Doyle, but he, like his colleagues, had reservations about Holmes’s methods and the misleading impression they gave to the public. Holmes worked with blinding speed, never expressed doubt, and presented his results with “mathematical” certainty (not unlike the CSI television shows of today). In contrast, Lacassagne’s investigations could continue for weeks. He made a point of maintaining uncertainty, right up until the end of the investigation. He famously told students, “One must know how to doubt.”22
Still, Lacassagne, like many colleagues, remained fascinated with the character. He published two reviews of Holmes stories in his journal and supervised a thesis by one of his students, comparing Holmes’s methods with those of actual forensic scientists. The student, Jean-Henri Bercher, archly referred to Holmes as “a veritable Robinson Crusoe of legal medicine” for his ability to accomplish alone what normally required a team of medical experts.23 He did find that Holmes and Lacassagne held certain values in common: their appreciation for careful observation and the methodical compilation of evidence; their belief that each case should be approached with a logical plan; their appreciation for how even the tiniest bits of evidence could point to a solution; and their belief in the necessity of preserving an untrammeled crime scene. In one story, Holmes excoriates an officer for allowing his men to trample through the site of a murder. “If a herd of buffalo had passed along there could not be a greater mess.”24 Like real-life investigators, Holmes appreciated the value of footprints, and he used plaster of Paris to preserve them. “There is no branch of detective science which is so important and so much neglected as the art of tracing footsteps,” said Holmes.25 “Happily, I have always laid great stress upon it.”
Sometimes the opinions of Holmes and Lacassagne were strikingly similar.26
Holmes (as quoted by Bercher): “It is a grave error to warm to a theory without having put together all the necessary materials: It could lead to false judgments.”
Lacassagne: “Avoid hasty theories and hold yourself back from flights of imagination.”
Yet their differences eclipsed their similarities. For example, Holmes deduced the height of a suspect by the length of his or her stride. Real medical examiners knew that the stride could vary depending on the suspect’s walking speed and emotional state. Holmes would take a single object from a person—a watch, for example—and use it to build an entire life history. Real examiners would never base conclusions on so narrow a piece of evidence. They collected, analyzed, and filed every piece of material they could find, and couched their conclusions in the understated language of science. Holmes knew the ash content of every popular cigar and cigarette—a useless piece of knowledge in real life. He had a cavalier approach to medicine, an understanding of anatomy that Watson himself characterized as “accurate but unsystematic.”27
Bercher found it particularly galling that Holmes never conducted autopsies, the cornerstone of legal medicine.28 For example, in A Study in Scarlet, Holmes deduces poisoning—probably by strychnine—with an examination that takes no more than a few minutes. “Arriving at the scene of the crime, Sherlock Holmes proceeds with several preliminary investigations to inquire into the circumstances, the habits of the victim … and he looks to see if he can’t find some suspect objects or traces of poison,” wrote Bercher.
Next he approaches the cadaver, and he makes a diagram of the position of the corpse, the state of his clothing, and traces of stains, marks of blows or wounds.… Moving the arms and legs, he investigates the state of rigor mortis, and gives an approximate time of death. We see him next approach the nostrils of the victim, and in one move discovers a characteristic odor.
The curtain falls on the first act: The corpse is removed and the autopsy is unnecessary!
There’s no question of doing research on lividity to reveal the position at death, which is of considerable importance. What matters the degree of putrefaction? A Sherlock Holmes has no need to surround himself with all that information to arrive at a conclusion! It is equally unnecessary to tire himself by doing an autopsy, and to get his hands dirty with pathological lesions that could present themselves in the thoracic and abdominal organs. Why dream of withdrawing some blood or viscera to try to discover traces of toxic substance?
As it happened, the same year A Study in Scarlet was published, Lacassagne also investigated a sudden death that turned out to have been strychnine-related.29 A pregnant woman in the countryside near Lyon drank some medicine for bronchial congestion and suffered a rapid and agonizing death. Unlike Holmes, the professor did much more than sniff the victim’s lips. Bringing in two other doctors as witnesses, he made extensive notes on the body’s position, lividity stains, and state of rigor mortis. Then he conducted a detailed autopsy, noting any internal hemorrhaging, blood clots, or other signs that might indicate the cause of death. He removed the brain, stomach, liver, kidney, uterus, segments of intestine and spleen, sealed them in jars, and had them sent back to his laboratory. Several other jars were sent back to the lab, as well; they contained stomach liquid, amniotic fluid, urine, and blood. Back at the institute, with the help of a physiology professor, Lacassagne injected samples of the victim’s stomach fluid into two frogs and into one medium-size laboratory dog. He injected a third frog with distilled water as a control. The frog injected with water survived, but all the other animals perished; the latter exhibited convulsions, contraction of the jaw muscles, stomach swelling, asphyxia, and then a rapid onset of rigor mortis—typical signs of strychnine po
isoning. The same symptoms had appeared in the woman. He gave the liquids to a chemistry professor, who found strychnine in the stomach fluid. Altogether, five doctors participated in the inquiry, which took place over a period of more than two days. In the end, a court convicted the woman’s pharmacist of negligence for accidentally contaminating her medicine.
Interspersed throughout the pages of Bercher’s thesis are comments in Lacassagne’s spidery handwriting, giving the impression that he, too, was debating Holmes’s methods and philosophy. On a strictly academic point, he questioned whether Holmes used “deductive” reasoning (arriving at specifics by starting at a general principle) or “inductive” reasoning (working from specifics to a more general idea). More fundamentally, he wondered how forensic detection could ever be considered the exact, almost mathematical science that Conan Doyle portrays. To his mind, there was art and intuition involved. Lacassagne commented that legal medicine involved three important components: craft, knowledge of science, and art. “One can learn craft,” he wrote.30 “By patience and work, one can become educated in science. But art springs from natural qualities, and is almost exclusively attributed to one’s [natural] mind.” He questioned whether the kind of cool, detached analysis employed by Holmes was always sufficient to arrive at the truth. “Isn’t there also ‘Inspiration,’ a spontaneous element, that ‘Quid Divinum’ [Divine Something] … between geometry and finesse?”
The inspirational quality pushed Lacassagne forward and resulted in his remarkable success rate. As he saw it, criminals were always moving into new territories of cleverness and depravity, and the modern investigator needed to develop new ways to pursue them. “All the silent witnesses … the place, the body, the prints … can speak if one knows how to properly interrogate them.”
The Killer of Little Shepherds Page 13
