The cause and manner of a death are not always evident, even after visual examination and dissection. From 1800 onward, scientific investigators continually devised procedures and instruments—technologies of visibility—to reveal what the naked eye could not see.
Chemical analysis helped detect traces of poison in the victim's body. Microscopes made it possible to see tiny lesions, crystals, and hairs.
Spectroscopic analysis of blood and other materials helped match trace elements linking victim and killer.
Toxicology
As commercially manufactured poisons became increasingly available in the 19th century, poisoning became known as a "modern" and disturbingly hard-to-detect method of killing. In response, researchers developed toxicology as a specialized field of forensic medicine, and devised specific tests for poison, most famously the 1836 Marsh Test for arsenic.
The new science of toxicology was plagued by difficulties. In the courtroom and laboratory, seemingly reliable tests were shown to be flawed. But, over time, toxicology's trials led to better knowledge of the action of poisons and better methods of chemical analysis.
Retail poisons Toxic cures
The Industrial Revolution introduced cheap poisons into homes, factories, and farms. To prevent accidents, poisons were sold in colorful and distinctively shaped bottles. But toxic substances were also used in widely available medical preparations, which poisoners could use to dispatch their victims.
Arsenic-based medicine, Wm. R. Warner & Co., about 1900
Courtesy National Museum of American History, Behring Center, Smithsonian Institution
Arsenic was widely used as a medicine in the 19th and 20th centuries. The development of forensic toxicology coincided with the spread of mass-produced and commercially distributed medicines and poisons (sometimes the same thing), and an associated rise in murders and suicides involving those substances.
Arsenic-trioxide tablets, Wm. R. Warner & Co., about 1900
Courtesy National Museum of American History, Behring Center, Smithsonian Institution
In France, in 1840, a notorious murder trial put the young science of toxicology to a dramatic test. Rumored to be unhappy in her marriage, Marie Lafarge, age 24, was charged with poisoning her husband Charles. Witnesses had seen her buying arsenic—to exterminate rats, she claimed—and testified that she had stirred a white powder into her husband's food. The prosecution sought to build on this by introducing the findings of local doctors who performed chemical tests on Charles Lafarge's stomach and on the white powders that had been gathered as evidence.
But Mme. Lafarge's lawyer strongly challenged the scientific methods and competence of the prosecution's medicalwitnesses, who were unacquainted with the improved test for arsenic which James Marsh, an English chemist, had devised four years earlier. As lawyers on both sides cross-examined the doctors, increasing doubt was cast on their methods and results. The judge ordered Charles Lafarge's body to be exhumed, and more tests to be performed by the doctors. These showed no evidence of arsenic—a result which, in turn, was contradicted by a new chemical analysis of food which Mme. Lafarge had prepared for her husband. As all of this played out in the courtroom, newspaper reporters provided a stream of stories: the Lafarge case became a media sensation.
In the end, both sides agreed to consult the highest authority, Mathieu Orfila, the eminent professor of forensic medicine, and the world's greatest expert on toxicology, who was summoned from Paris. Orfila conducted Marsh tests on samples taken from Charles Lafarge's body and the soil around the burial site. He found definite traces of arsenic in the body, and showed that it did not come from the surrounding soil. The defense's last gasp was to summon yet another expert witness, François Raspail, Orfila's bitter enemy, who had already jousted with him in a previous case.
Raspail arrived too late: the verdict had already been given. Mme. Lafarge was found guilty of murder, and received a death sentence, which was later commuted to life in prison. But the controversy continued. Although Orfila's performance of the Marsh test for arsenic was publicly celebrated as a vindication of forensic science, Raspail and his allies charged that Orfila's analysis was also flawed, and that Marie Lafarge was innocent.
Marsh Test Apparatus from Microchemistry of Poisons, including their Physiological, Pathological, and Legal Relations, Steel engraving by Theodore G. Wormeley, MD, 1864
Courtesy National Library of Medicine
The Marsh Test
In 1832 police arrested John Bodle for lacing his grandfather's coffee with poison. Chemist James Marsh tested the drink in his laboratory, and confirmed the presence of arsenic by producing a yellow precipitate of arsenic sulfide. But the precipitate was unstable and, by the time of trial, had deteriorated. Without forensic proof, Bodle was acquitted. Stung by the verdict, Marsh devised a test that could better stand up in court. His 1836 "Marsh Test" won worldwide acclaim and became a standard procedure. But in subsequent decades Marsh's test was shown to be problematic, and in turn underwent a series of improvements.
Group 10
Mathieu Joseph Bonaventure Orfila (1787–1853)
Born a Spanish subject, on the island of Minorca, Orfila first studied medicine in Valencia and Barcelona, before going to study in Paris. His first major work, Traité des poisons tirés des règnes minéral, végétal et animal; ou, Toxicologie générale, was published in 1814. After a failed attempt to set up chemistry professorships in medical colleges in Spain, he returned to France. In 1816, he became royal physician to the French monarch Louis XVIII. In 1817 he became chemistry professor at the Athénée of Paris, and published Eléments de chimie médicale, on medical applications of chemistry. In 1818 he published Secours à donner aux personnes empoisonnées ou asphyxiées, suivis des moyens propres à reconnaître les poisons et les vins frelatés et à distinguer la mort réelle de la mort apparente. In 1819 he became a French citizen and was appointed professor of medical jurisprudence. Four years later, he was made professor of medical chemistry.
He became dean of the Faculty of Medicine in 1830 and reorganized the medical school, raised educational requirements for admission, and instituted more rigorous examination procedures. He also helped to establish hospitals and museums, specialty clinics, botanical gardens, a center for dissection in Clamart, and a new medical school in Tours.
During his long career, Orfila was called to act as a medical expert in widely publicized criminal cases, and became a notable and sometimes controversial public figure. Exacting in his methods, Orfila argued that arsenic in the soil around graves could be drawn in to the body and be mistaken for poisoning. He conducted many studies and insisted that testing of soil be part of the procedure in all exhumation cases.
He was a prominent member of the Parisian social and intellectual elite, and a regular attendee (and host) of salons in the 1820s and 1830s. But his zealous activities as dean, his prolific writings on polarizing issues, and his ardent pro-monarchist politics made him numerous enemies. After he was removed from his post as dean during the 1848 revolution, a commission was set up to investigate illegal or irregular acts during his tenure, but found none. By 1851, he was rehabilitated and elected president of the Academy of Medicine.
Mathieu Joseph Bonaventure Orfila, about 1835
Mathieu J.B. Orfila, M.D., and Octave Lesueur, M.D., Traité de Médecine Légale… [Treatise of Legal Medicine…], Paris, 1848
Courtesy National Library of Medicine
Orfila, a Parisian medical professor, wrote the first medical treatise devoted solely to the subject of toxicology in 1815.
Studies of the effects of decomposition on exhumed bodies from Traité des exhumations juridiques…, written by Mathieu J. B. Orfila, MD, and Octave Lesueur, MD, illustrated by Hippolyte Vanderburch, 1831
Courtesy National Library of Medicine
Orfila was a towering figure in the emergent field of forensics. His 1831 treatise was the first book to be devoted solely to the subject of exhumation and decomposition.
Studies of the effects of decomposition on exhumed bodies from Traité des exhumations juridiques…, written by Mathieu J. B. Orfila, MD, and Octave Lesueur, MD, illustrated by Hippolyte Vanderburch, 1831
Courtesy National Library of Medicine
Orfila was a towering figure in the emergent field of forensics. His 1831 treatise was the first book to be devoted solely to the subject of exhumation and decomposition.
Studies of the effects of decomposition on exhumed bodies from Traité des exhumations juridiques…, written by Mathieu J. B. Orfila, MD, and Octave Lesueur, MD, illustrated by Hippolyte Vanderburch, 1831
Courtesy National Library of Medicine
Orfila was a towering figure in the emergent field of forensics. His 1831 treatise was the first book to be devoted solely to the subject of exhumation and decomposition.
Microscopy
Woodward's photomicrography apparatus from The Army Medical Museum catalog, 1867
Courtesy National Library of Medicine
The invention of photomicrography
In the 1870s, U.S. Army surgeon Joseph Janvier Woodward invented a technique of photographing objects seen under a microscope.
Woodward's photomicrographs—made with a room-sized apparatus that used direct sunlight as the light source—caused a sensation when exhibited at the 1876 Centennial Exposition in Philadelphia. After further development, photomicrography enabled forensic investigators to make visual records of what they saw. The photographs served as an aid to analysis and could be presented as evidence in the courtroom.
Definition
Photomicrograph: A photograph of a microscopic view; a photograph of what one might see looking through a microscope. In contrast, a microphotograph is a very small photograph that can only be seen with the aid of a microscope.
Dr. J. J. Woodward's Microscope, 1864
Courtesy National Museum of Health and Medicine, Armed Forces Institute of Pathology, Washington, DC
Woodward's photomicrography apparatus, c. 1876
Courtesy National Museum of Health and Medicine, Armed Forces Institute of Pathology, Washington, DC
Human hair seen through a microscope from A study of hairs and wools belonging to the mammalian group of animals, including a special study of human hair, considered from the medico-legal aspects, John Glaister Jr., MD, 1931
Courtesy National Library of Medicine
A healthy hair bulb from A study of hairs and wools belonging to the mammalian group of animals, including a special study of human hair, considered from the medico-legal aspects, John Glaister Jr., MD, 1931
Courtesy National Library of Medicine
Transverse hair sections from A study of hairs and wools belonging to the mammalian group of animals, including a special study of human hair, considered from the medico-legal aspects, John Glaister Jr., MD, 1931
Courtesy National Library of Medicine
Red hair from A study of hairs and wools belonging to the mammalian group of animals, including a special study of human hair, considered from the medico-legal aspects, John Glaister Jr., MD, 1931
Courtesy National Library of Medicine
Hair in old age from A study of hairs and wools belonging to the mammalian group of animals, including a special study of human hair, considered from the medico-legal aspects, John Glaister Jr., MD, 1931
Courtesy National Library of Medicine
Guinea pig blood crystals from Die Blutkrystalle; Untersuchungen [The Blood Crystal; Investigations], Wilhelm Preyer, 1871
National Library of Medicine
Baboon blood crystals from Die Blutkrystalle; Untersuchungen [The Blood Crystal; Investigations], Wilhelm Preyer, 1871
National Library of Medicine
Spectroscopy
Spectroscopy was born in the mid-17th century, when Isaac Newton discovered that a prism divides white light into constituent colors. Subsequent researchers discovered that specific substances, subjected to flame, give off unique patterns of light that show characteristic "emission" bands and "absorption" lines when cast through a prism.
By the 1870s and 1880s, spectroscopy seemed a promising new forensic technology. Further work on spectra analysis led to spectrophotometry and, more recently, mass spectrometry. In tandem with gas chromatography, mass spectrometry is now often used to identify and match organic and inorganic substances for forensic purposes.
Spectroscope, about 1920
Spectroscope, about 1920
Courtesy National Museum of American History, Behring Center, Smithsonian Institution
Spectral detection
In the 1850s, Robert Bunsen and Gustav Kirchhoff devised the first working spectroscopes. Two decades later, Georg Dragendorff and other scientists began using spectroscopy for medical research and criminal investigations.
The fields of toxicology and serology—the study of blood and other body fluids—were the first to benefit. A small specimen of blood, subjected to a flame from a Bunsen burner, gave off light that could be subjected to spectroscopic analysis. This analysis could reveal the presence of carbon monoxide and other poisons.
Spectroscopic Apparatus from On Spectrum Analysis, steel engraving by Henry Enfield Roscoe, PhD, 18690
Courtesy National Library of Medicine
Chart showing the spectra of different types of blood samples from A System of Legal Medicine, Allan McLane Hamilton, MD and Lawrence Godkin, MD, 1894
Courtesy National Library of Medicine
On Spectrum Analysis, Henry Enfield Roscoe, PhD, 1869
Courtesy National Library of Medicine
Roscoe's book helped to popularize spectroscopy. The new technology's potential applications to forensic medicine sparked great enthusiasm.
Diagram of the Model DU Spectrophotometer, showing Mounting Block, Cell Compartment, Phototube Housing and Lamp Housing detached from the Monochromator National Technical Laboratories, from Beckman Bulletin 91-C, 1947
Courtesy National Museum of American History, Behring Center, Smithsonian Institution and Beckman Coulter, Inc.
Black Box Effect
In the 1940s the Beckman spectrophotometer revolutionized the laboratory. Encased in a metal container, the device occupied less counter space than conventional bench apparatus, and hid the procedures inside a box. A technician placed a specimen on a slide, inserted it into the instrument, and recorded the readings.
Historians of science theorize that "black box" devices are basic to modern laboratory practice. A device and its output replace the hand, eye, and judgment of the scientist. The standardized inner workings and seemingly objective output of the black box can more easily evade or withstand legal scrutiny.
Beckman DU spectrophotometer, c. 1950
Courtesy DeWitt Stetten, Jr. Museum of Medical Research, National Institutes of Health
The DU spectrophotometer measures the amount of ultraviolet light absorbed by a substance. Developed by Arnold Beckman at National Technical Laboratories to measure the amount of vitamin A in food, it came to be widely used to identify and measure a variety of substances. The DU spectrophotometer was one of several revolutionary devices invented by Beckman: the first "black boxes" in the chemical laboratory. It revolutionized laboratory work by replacing labor-intensive and bulky (and openly visible) chemical procedures with a simple, boxed electronic instrument in which only input and output could be seen.
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