Toxicology - An Introduction
Extract of nux vomica
“Fear nothing; your crime will go unpunished. There is no corpus delecti, for it cannot be found.”
The sentiment was a common one among prosecutors, police, and scientists in the latter half of the nineteenth century. This particular lament comes from a French prosecutor during a murder trial where the weapon of choice was morphine. The quote has been edited for dramatic effect, but we’ll get into that further on.
The detection of poisons was not as impossible a situation as the quote would suggest. Law enforcement in this period seem almost impotent against poisonings, but that’s because they were starting from nothing. Great advancements were made in science in the 1800s which lay the foundation for the discoveries that came in the next century. You cannot find poison if you don’t know what to look for and for most of history, they didn’t.
Proof of poisoning requires more than opening up a corpse and examining the organs. (Medical knowledge and what internal organs of a poison victim looked like are for later blogs). Suffice it to say, medical practitioners were able to identify whether or not the organs were “normal” or damaged, but they were unable to determine the cause. Our understanding of the body was in its infancy and operated according to the Galenic theory of four humors (phlegm, blood, yellow bile, and black bile). Illness was the result of an imbalance of these humors. Even today, with all our medical knowledge, it is almost impossible to identify the existence of poison by looking at the organs. Much of the damage done by poisons mimics other conditions. To know for certain, tests have to be done.
For most of history, even when autopsies were carried out, cause of death was vague and inaccurate or declared “indeterminate.” Because of the uncertainty, practitioners were reluctant to make the declaration of poison, but were often willing to acknowledge it as a possibilty.
Autopsies were carried out during the famous Affair of the Poisons (1677 to 1682) during the reign of Louis XIV (the Sun King). One of them was on Henrietta Anne, sister of King Charles II of England and sister-in-law to King Louis. (Her husband was Philippe, Duke of Orléans.) Henrietta’s death was attributed to “very boiling bile, very corrupt and malign, and very impetuous, which caused all the disorders in the above said parts.” (City of Lights, City of Poison) Given the circumstances of her death, and her husband’s severe displeasure with her, today, it is believed that she likely had been poisoned.
Suspected poisonings were investigated and determined based on circumstantial evidence. What was the victim’s health just prior to their death? Were they violently ill? Was the condition chronic? What symptoms were present? On other occasions, they fed animals the victim’s last meal and waited to see if they died which was inexact and not always possible. For most Convictions resulted from confessions under torture. For most of history, except on rare occasions, poisoners walked free.
The nineteenth century saw many scientific advancements in all fields, including medicine. For our purposes, the most significant was the chemical revolution in which elemental chemists devised methods for isolating and identifying elements and compounds. This is the era when elements were discovered, their qualities, such as valence and atomic weight, recorded (or predicted), Periodic Law established, and the periodic table of elements created by Russian scientist Dmitri Mendeleev in 1869. Within the first decade rhodium, palladium, cerium, osmium, iridium (1804), sodium, potassium (1807), magnesium, barium, calcium, strontium (1808), and chlorine (1810) were isolated and identified.
Scientific curiosity, not law enforcement, was the driving force behind the experiments and most researchers were not thinking of poison detection or prosecuting murderers when they went in search of the chemicals that were the basis for life. Fortunately, most does not mean all.
In 1814, Spanish chemist Mathieu Orfila published his Treatise on Poisons, the first of its kind. He went on to be known as the Father of Toxicology. His research was focused entirely on proving the presence of poison in corpses. This was different than simply identifying the substance. It was one thing to isolate and identify a chemical, quite another to detect it in human tissue. The barbital class of drugs was discovered in 1864 by Adolf von Baeyer, and in 1912 phenobarbital was synthesized and used therapeutically. It was not until the 1970s that toxicologists were able to test for its presence in humans (living or dead).
It should be noted that, in the 1800s, finding poison in a corpse was not sufficient to declare it as the cause of death; you had to know how much. Most people had trace amounts inside them. Ingredients such as opium, arsenic, and asbestos were present in everyday items including cosmetics and tonics to improve health prescribed by medically trained practitioners. Their easy availability contributed to their appeal and the presence of bottles of poison in the household was not an indicator of guilt as it would be today.
Orfila concentrated first on metallic poisons, such as arsenic, believing they would be easiest to detect. He, and others, met with success. By the middle of the century science was finding ways to thwart poisoners. Alfred Taylor developed a test for arsenic in tissue, which was soon improved upon by James Marsh (1836). The number of convictions went up across Europe. Not surprisingly, instances of arsenic poisonings decreased, but other substances filled the void. These came in the form of alkaloids (carbon-based, plant poisons).
A nefarious side effect of scientific discovery was the creation of more poisons. As some scientists were discovering methods for detecting poisons, others were inadvertently widening the catalogue available to would-be murderers. Morphine was isolated in 1804, strychnine and coiine (from hemlock) followed in 1819, nicotine was extracted from tobacco leaves in 1828, and aconitine (monkshood) in 1832.
This brings us back to our disheartened prosecutor. He was not bemoaning the inability to detect all poisons; he was advising murderers to abandon metallic poisons in favor of the “new ones.” As with their metallic cousins, isolation of alkaloid poisons in tissue was more complicated and elusive that extracting them from their source. Orfila and others tried and failed repeatedly.
Things began to change in 1860, Belgian chemist Jean Servais Stras developed a method to isolate nicotine in a corpse. Other plant poisons became accessible to criminal investigators; science was catching up.
Devising a test was not enough. Information was not disseminated as rapidly or as easily as it is today. Even published scientific discoveries could remain obscure and their implementation kept local if the journal they were published in did not have a wide distribution or their articles were not available in translation. Case in point, neither Alfred Taylor nor James Marsh were the first to develop a test for arsenic in tissue. That honor belongs to German pharmacologist Valentin Rose. In 1806 he was able to extract arsenic by boiling stomachs and intestinal tracts. The test was used in 1809 in the trial of Anna Margaretha Zwanziger, a Bavarian housekeeper accused of multiple murders. Rose’s test showed the presence of arsenic in three exhumed corpses and Anna confessed. She was executed in 1810.
Other information was more mobile. Though much of the science was being done in Europe, the science of toxicology spread to North America. In 1896 Columbia University chemist Rudolph Witthaus and law professor Tracy C. Baker, published Medical Jurisprudence, Forensic Medicine and Toxicology, the first treatise of its kind in America.
There was still a ways to go. Knowing there was a test, and knowing the mechanics of the test, did not ensure accuracy. Not just anyone with a scientific or medical background could perform the test properly.
In 1840, Marie Capelle Lafarge went on trial for poisoning her husband with an arsenic-laden cake. The Marsh Test was carried out and arsenic was detected. During the trial, the defense responded by bringing in two apothecaries from Limoges to repeat the test. Their findings came back negative for arsenic. Prosecutors insisted that a third test be carried out and that Mathieu Orfila be brought from Paris to perform it. This third test was positive for arsenic. Orfila explained that the Marsh Test was delicate and that a level of expertise and experience were required for the test to be accurate. A simpler method to detect arsenic was devised by Hugo Reinsch in Germany in 1842.
No discussion of the role of science in criminal prosecutions can be made without reference to the jury. It is not sufficient to have the technology, and the individuals capable of implementing it. For a conviction to be won, the jury, and the public, have to trust that the science and expertise of those who testify about it are correct. In 1859, toxicology suffered a significant setback, not in science, but in reputation. Dr. Thomas Smethurst was arrested and put on trial at the Old Bailey for poisoning Isabella Bankes (his wife through bigamy). An eminent pathologist and toxicologist, Professor Alfred Swain Taylor, performed the Reinsch Test using the contents of Miss Bankes’ chamber pot, and the results proved positive for arsenic. During her autopsy it was noted that her intestines were greatly inflamed, which is consistent with arsenic poisoning, but a second test using her internal organs came back negative for arsenic. How could it be present in bodily fluids before death but absent in the body afterwards?
The Reinsch Test involves mixing the suspect material (in this case the contents of the chamber pot, and subsequently, her organs) with hydrochloric acid, then heating it. A mesh of copper is inserted and if a dark grey coating appears on it, then arsenic is present. Simple, straightforward. Or it should have been. Further testing revealed that the copper mesh used by Taylor to examine the chamber pot’s contents had been used in many previous tests and was contaminated with arsenic. Despite the confusion about the presence of poison, Dr. Smethurst was convicted and sentenced to hang, but public outrage and an appeal to Queen Victoria by his first, and legal, wife, had his sentence overturned. For years afterward, “expert” medical testimony was tainted in the public eye.
Other cases did equal damage. Mrs. Adelaide Bartlett was accused of murdering her husband, Edwin (1886), and, despite the cause of death being a stomach full of chloroform she walked free. The bickering of experts and their contradictory theory as to how that much chloroform (a caustic liquid) could be ingested without the servants hearing the victim’s screams, confused the jury.
A history of toxicology and law enforcement is about more than dates on a timeline. It’s the development of scientific procedure, the dissemination of knowledge, and a public’s willingness to accept the word of experts.
As new, easier, more accessible, and more reliable tests for poisons and toxins were developed, toxicology became a valuable weapon in law enforcement’s arsenal. The work done in the nineteenth century, laid the foundations for the advancements of the twentieth.
Bibliography
Balko, Radley, “A Brief History of Forensics.” Washington Post. Online.
https://www.washingtonpost.com/news/the-watch/wp/2015/04/21/a-brief-history-of-forensics/
Blum, Deborah. The Poisoner’s Handbook. (New York, NY: Penguin Press, 2010).
Eastoe, Jane. Victorian Pharmacy. (London: Pavilion, 2010).
Evans, Colin. The Father of Forensics. (New York, NY: Berkley Books, 2006).
Stratmann, Linda. The Secret Poisoner: A Century of Murder. (New Haven, Connecticut: Yale University Press, 2016).
Tucker, Holly. City of Light, City of Poison: Murder, Magic, and the First Police Chief of Paris. (New York, NY: W. W. Norton & Company, 2017).
Wagner, E. J. The Science of Sherlock Holmes. (New York, NY: John Wiley & Sons Inc., 2006).