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  The next major advance in the use of lenses was around 1590, when the Dutch spectacle makers, father and son Hans and Zaccharias Janssen, began experimenting with lenses by spacing several out along the inside of a tube. They found when placing an object under a lens and looking at it through the lenses in the tube, the object was greatly magnified. They had created the compound microscope (a microscope that uses more than one lens).

  The Janssens later claimed to have invented both the microscope and the telescope, though who was ultimately responsible for the successful creation of either remains open to debate as both work in very similar ways. A microscope uses a short focal lens to magnify a close-range object, then this image is viewed through a long focal-length lens in the eyepiece. A telescope, on the other hand, uses a long focal lens to magnify objects far away, and a short focal lens is used in the eyepiece to view the magnified image. A lens-maker named Hans Lippershey (c. 1570—c. 1619) lived yards apart from the Janssens in Middelberg and also claimed the credit for both inventions. As Lippershey was the first to apply for the design patent of the telescope, he is now usually attributed with its invention, while Janssen is credited with the invention of the single-lens and compound optical microscope. Aside from this there is no evidence to prove conclusively in favor of either claimant. There are a whole series of confusing and conflicting claims taken from the testimony of friends and family during the many investigations that took place over the issue. In any case, the date of invention for the microscope is commonly given as between 1590 and 1595.

  Despite such significant developments in the use of lenses for magnification, it was not until the mid-seventeenth century that the microscope was used in Europe for in-depth scientific examination. One of the first examples is the publication of The Fly’s Eye in 1644. This detailed study of the anatomy of insects using a microscope was by the Italian astronomer and priest Giambattista Odierna, who was self-educated in science.

  However, it was another Italian, the physician and biologist Marcello Malpighi (1628–1694), who truly pioneered the use of microscopes in biological study. While examining the structure of the lungs under a microscope in 1661, he observed that the lining of the lungs contained balloon-shaped sacs (alveoli), which were in turn connected to branch-like structures leading from small arteries and veins (capillaries). This historic discovery not only explained how oxygen is moved from the lungs into the blood, but also founded the science of microscopic anatomy, a field in which Malpighi made many significant discoveries throughout his career.

  Following this, one of the greatest contributions to microscopy came from Dutch microscopist Antonie van Leeuwenhoek (1632–1723). Leeuwenhoek’s fascination with developing and improving microscope lenses eventually enabled him to examine objects as small as one millionth of a meter. In 1674 he was the first man to discover single-cell organisms (now called microorganisms), including bacteria and sperm. In 1684, his advancements in microscopy enabled him to publish the first accurate observation of red blood cells. His work was confirmed by philosopher Robert Hooke (1635–1703), whose earlier work Micrographia, published in 1665, was widely respected for its intricate and accurate drawings of insects and organisms seen through a microscope. Leeuwenhoek’s development of the microscope laid the foundations for future microbiology as well as promoting the use of microscopes for scientific study from the late seventeenth century onward.

  Further improvements to the microscope came in 1893 when the German scientist August Köhler developed a method to better illuminate microscope samples. He wanted to produce high-quality photographs from a microscope but was hindered by the uneven distribution of light supplied by then-achievable methods of illumination such as gas lamps. To remedy this, he used a collector lens to focus an image of an illuminating lamp into the front focal plane of the microscope, producing an evenly illuminated field of view without optical glare. Köhler illumination is still a central process in contemporary light microscopy.

  Eighteenth-century microscopes on display at the Musée des Arts et Métiers in Paris. August Köhler’s methods of illumination were to radically improve the images obtainable from microscopes such as these. This technology increasingly found its way into contemporary biology and, by extension, forensic science.

  In 1891, before Köhler had even invented his new method of illumination, microscopic techniques finally made their way into the field of criminal investigation with the publication of Handbuch für Untersuchungsrichter, Polizeibeamte, Gendarmen (Handbook for Coroners, Police Officials, Military Policemen). Written by Austrian professor and judge Hans Gross (1847–1915), this groundbreaking book laid out why examining evidence under a microscope could be a vital step in solving crime. As this was the first book to combine the two fields of microscopy and criminal investigation, Hans Gross is considered by many to be the father of criminalistics.

  Gross said of the emerging field: “A large part of a criminalist’s work is nothing more than a battle against lies. He has to discover the truth and must fight the lie. He meets the lie at every step.” Of course, the trick is not only recognizing a lie, but also proving that it is a lie. It is the forensic scientist’s job to see through the criminal’s “cleverness” and get to the truth. At times this can be extraordinarily difficult, particularly if one is dealing with a criminal of great cunning.

  Gross highlights such a case, which he came across in an old record, in which a young man was believed to have burned down the house of a farmer. The young man was the prime suspect for the crime, as it was widely known that he resented the farmer and used to work at the mill opposite the farmer’s home. However, having left his occupation nine months previously, he was nowhere near the farmhouse at the time of the incident. On examining the scene, the investigating officers found evidence that, while still employed at the mill, the young man had constructed a device to set fire to the farmer’s home at a later time. First he had stretched a strong spring and cord across a skylight in the granary that faced the house. Securing the spring with pitch, he had then arranged flammable material and a magnifying glass underneath the cord. Nine months later, the lens caused the sun’s rays to focus onto the flammable material and ignite it. This in turn ignited the cord, which snapped, causing flaming pitch to catapult from the skylight onto the farmer’s house.

  While the complexity of the contraption might make us suspect this story to be apocryphal, for Gross it was a prime example of it being the criminalist’s role to examine the evidence, see through the criminal’s ingenuity, and expose the truth.

  The reason that Gross’s Handbook for Coroners, Police Officials, Military Policemen is such an important publication in the history of forensics is that it combined in one volume information from several different fields of knowledge, including psychology and science, and presented it in such a way as to maximize its usefulness for those involved in criminal investigation. The contents also reflected the latest emerging trends in detection; by this time the work of Bertillon had lost much appeal with criminologists outside of France. Bertillon himself had been somewhat disgraced over the theft of the Mona Lisa in 1911; a palm print was found and Bertillon had no way of discovering whose it was, despite, as it turned out, having taken the measurements of the thief (an unbalanced Italian named Vincenzo Perugia) some years before. Gross’s book placed far more emphasis on fingerprinting, and additionally pointed to the value of analysis of dust, hairs, wood fibers, and other kinds of trace evidence.

  Gross went on to found the Institute of Criminalistics in 1912 (which later became the Institute of Criminology) as part of the University of Graz Law School. This was to be the first of many similar institutes opened all over the world, formalizing Gross’s conception of criminalistics as a discipline in its own right.

  One case that Gross investigated serves as an excellent example of the value of gathering trace evidence for analysis under a microscope. While walking their dog by the sea one day, three little girls underwent a frightening ordeal.
They were accosted by a man who first exposed himself to them, then sexually assaulted them, placing his penis inside their underwear. When they returned home, terrified, they immediately informed their parents, who called the police. The police followed standard procedure and collected all the clothing that the girls had been wearing at the time. When examined, the underwear of all three girls was found to have semen stains inside the crotch.

  The following day one of the girls was out walking with her mother and was shocked to see the man who had assaulted her. The girl pointed him out and he was quickly arrested. Semen stains were discovered in and around the flies of his trousers. This seemed to confirm the girls’ story but on its own was hardly conclusive proof of his guilt. However, a dog hair was also recovered from the trousers, as well as some colored wool fibers. When these were examined under a microscope, the hair turned out to be an exact match for those from the girls’ terrier and the fibers to be an exact match for the dresses that the girls had been wearing. The case was proven. This was not just a triumph for justice and for Gross, but also an eloquent demonstration of the power of the microscope in dealing with trace evidence.

  An unlikely leader in the field of forensic microscopy was Georg Popp (1863–1941) from Frankfurt, Germany, who had originally trained as a chemist. Although experienced in microscopic techniques from his work in laboratories, it was only in 1900 that he gained his first taste of forensic microscopy, when a criminal investigator asked him to use his expertise to examine some evidence. It was the beginning of a lifelong fascination and a career in criminology. In 1889 he even founded his own laboratory, the Institute of Forensic Chemistry and Microscopy, which dealt with toxicological scientific analysis for the purpose of criminal investigations.

  Influenced by Gross’s book, he was a firm believer in the importance of fingerprints and in the practice of photographing them. He was even able to use his knowledge in this area—and in chemistry—to solve a crime that had occurred in his own lab. During the course of a theft, the culprit had touched a piece of platinum. Popp exposed this to vapors of ammonium sulphohydrate which caused fingerprints to show up in black wherever the thief had touched. From these it was soon possible to identify the perpetrator as a man who used the laboratory on a regular basis.

  Fingerprints were also involved in one of the first cases to bring Popp to the attention of the public, when he was instrumental in solving the murder of a piano dealer in Frankfurt—he discovered and photographed prints at the scene of the crime and then compared them with suspects until he got a match. However, the case that really made him famous revolved around trace evidence, not fingerprints.

  In October 1904, a young woman named Eva Disch was found dead in a bean field in Frankfurt. The postmortem examination showed that she had been raped then strangled to death with a scarf. A stained handkerchief had been found at the scene. Popp examined it under a microscope and found nasal mucus containing traces of coal, snuff, and the mineral hornblende.

  Using this evidence, a man by the name of Karl Laubach soon became the prime suspect. He was known to use snuff and worked in a coal-burning gasworks as well as part-time in a local gravel pit that contained a large quantity of hornblende. Popp examined Laubach’s fingernails and found coal and grains of minerals including hornblende underneath them. On examining Laubach’s trousers, he found further evidence. Soil samples taken from them revealed two layers; the sample from the lower layer, directly in contact with the cloth, contained minerals that matched those taken from the crime scene. The upper layer contained particles of crushed mica mineral, which matched soil samples taken from the path from the murder scene to Laubach’s home. Popp concluded that Laubach had picked up the first layer of minerals from the crime scene, before the layer of mica was added on top of it on his way home. Once confronted with this evidence, Laubach confessed. One of the Frankfurt newspapers of the day carried the headline “The Microscope as Detective” in homage to Popp’s painstaking investigation.

  Popp garnered further nationwide acclaim in 1908 when he was instrumental in bringing the murderer of a woman named Margarethe Filbert to justice. On May 29 that year, in Rockenhausen in Bavaria, an architect reported his housekeeper—Filbert—missing. She had taken a train to a nearby village the previous afternoon in order to go on a walk through the valley of Falkenstein, to see its ruined castle. She had failed to return home that evening.

  After several days of searching, the police discovered her headless corpse in the woods. The initial impression given by the gruesome scene was that it had been some kind of sex crime; Filbert was lying on her back with her legs apart and her skirts pushed up. However, a later postmortem showed no sign of sexual assault. It was also noted that her purse, hat, and parasol were missing, meaning that robbery could not be ruled out as a motive. The pathologist who examined the body concluded that she had been strangled before having her head removed using a sharp knife. Hairs were discovered in her hands.

  A local magistrate, alarmed by the savagery of the crime and aware of Popp by reputation, traveled to Frankfurt to seek his guidance in the case. He quite rightly felt that the hairs might be a vital clue that would reveal the identity of the killer and asked Popp to examine the evidence. Unfortunately, Popp quickly ascertained that the hairs came from Filbert’s own head. However, he was now intrigued by the case and offered to continue his investigation.

  The main suspect was a local factory worker named Andreas Schlicher, who was also a poacher whom witnesses claimed they had seen near the field on the day of the crime. When questioned he became indignant, denying any involvement with the murder. When a pair of his trousers, his gun, and its ammunition were discovered at the nearby castle, he claimed to have left them there the day before the murder, saying he often did this to avoid alerting people to his poaching. Bloodstains were found on the knees of the trousers. When Popp soaked them in salt water and carried out the Uhlenhuth test, the reaction of the serum indicated that it was human blood. Further spots of blood were found on Schlicher’s jacket, though it seemed that he had tried to wash them out. The evidence against him was mounting, though for the time being was still inconclusive.

  Popp then became interested in the encrusted soil on Schlicher’s shoes. It had been established that Schlicher’s wife had cleaned his shoes the day before the murder and that he had not worn that particular pair since the day of the murder. Together with a geologist, Popp collected soil samples from the area near the murder, from the area where Schlicher’s possessions were found, and from near his house. Popp found that the samples taken from the murder scene contained decomposed red sandstone, angular quartz, ferruginous clay, and a little vegetation. In distinct contrast, the samples from Schlicher’s home contained fragments of porphyry, milky quartz, and mica, as well as root fibers, weathered straw, and leaves. The area around the house was also littered with greenish goose droppings. Finally, the sample from the area where Schlicher’s possessions had been found contained brick dust, coal, and pieces of cement that had fallen away from the crumbling castle walls.

  Armed with this information, Popp examined Schlicher’s shoes. He found the sole encrusted with a thick layer of soil. Given that the shoes had been cleaned and then not worn except on the day of the murder, Popp reasoned that the soil could only have accumulated on that day and that therefore each layer would contain a sequence of deposits from where Schlicher had been on the day of the murder.

  He carefully removed the layers one by one. The earliest layer, attached directly to the shoe, consisted of goose droppings. On top of this was a layer of grains of red sandstone, and on top of that a mixture of coal, brick dust, and cement fragments. These were obviously comparable to the samples that Popp had taken from the various locations of significance to the case. Schlicher claimed to have been walking in his own fields that day but no fragments of porphyry with milky quartz were found in the soil on the shoes, which would have been the case if he were telling the truth. On the other hand, it see
med clear that the goose droppings came from near his home, the red sandstone from the scene of the crime, and the coal, brick dust, and cement from the castle.

  Faced with this compelling evidence against him, Schlicher finally confessed to the murder of Margarethe Filbert. From her appearance he had thought she was rich and decided to rob her. When he realized she had no money, he had attacked her in anger and cut her head off and hidden it. He was initially sentenced to death, though this was later commuted to life imprisonment.

  The Margarethe Filbert case established Popp at the forefront of forensic geology and confirmed the vital role that soil samples play in criminal investigation (see Plate 9). The great Hans Gross had always maintained that the dirt on someone’s shoes would eventually prove more compelling than a confession obtained by intensive interrogation. Popp had proved him right.

  Microscopes continued to be promoted by other scientists as well. Professor Alexandre Lacassagne, a French physician and leading criminologist, impressed their usefulness upon his students at the Lyon Institute of Forensic Medicine. One of these students, Emile Villebrun, went on to become a leading forensic authority himself, specializing in fingernails—in the marks they leave and the value of material that might be discovered underneath them. He wrote a thesis on the subject and also solved a number of serious crimes. But perhaps the most famous of those who studied under Lacassagne is a man whose name we have already mentioned more than once: Edmond Locard.

  Locard was born in Lyon in 1877. First educated at the Dominican College at Ouillins, he subsequently attended the University of Lyon and graduated with a doctorate in medicine and a licentiate in law. He had developed a passion for all things forensic from an early age, spending his childhood reading Arthur Conan Doyle’s Sherlock Holmes stories. After earning his doctorate in medicine, he was fortunate enough to be taken under Lacassagne’s wing as his assistant. While still studying under him, Locard became convinced that France, not to mention forensic science as a discipline, needed a real laboratory of crime, a laboratory completely dedicated to examining criminal evidence. This was extremely ambitious; the idea had been tried by others, including the famous Bertillon, before, and had always been met with indifference or even hostility. But Locard was determined not to let the shortsightedness of doubters and critics hamper him, so, after much persuasion on his part, in 1910 the police department of Lyon allowed him to create the first police laboratory in the attic rooms of the Lyon courthouse. However, the department did not officially recognize Locard’s laboratory until 1912. He needed to prove himself, and his opportunity arrived in 1911.