Forensic Science and the Quest for Certainty

Foxglove. Courtesy of Wikimedia Commons

Foxglove. Courtesy of Wikimedia Commons.

Agatha Christie fans are well acquainted with the poisonous properties of foxglove, Digitalis purpurea, the pretty, bright-purple plant found on roadsides throughout the United States. Foxglove and its active agent, digitalis, was used for medicinal purposes for centuries, especially as a diuretic in cases of dropsy (oedema). Robert Christison (1797–1882), a professor of medical jurisprudence at the University of Edinburgh, was among the first to provide a systematic account of its properties as a poison. In his Treatise on Poisons, in relation to Medical Jurisprudence, Physiology, and the Practice of Physic (a copy exists in the CHF Library), Christison made foxglove seem like a poisoner’s dream. It was insoluble in water and very bitter, but dissolved easily in alcohol, which could also mask the taste. It could be applied to a wound or injected into a vein. Like mercury, it could be fatal when given in too large a dose as a medicine; also like mercury, Christison wrote, it possessed the singular property “of accumulating silently in the system, when given long in moderate doses” and produced “constitutional effects, even after it has been discontinued.”

Christison referred to one fatal case that made it to trial at London’s Old Bailey, the central criminal court in England. A medical practitioner, Jacob Evans, was indicted for manslaughter in the death of Camp Collins, a 17-year-old apprentice in the household of John Burbridge, cabinetmaker. Evans was accused of giving Collins 6 ounces of foxglove, “well knowing the same to be a deadly poison.” Collins had been ill off and on for several months. His parents approached Evans, who had written a book on herbal remedies, to treat the boy. On arriving at the shop, Burbridge told the court, Evans had said, “I have brought the stuff, I should like you to take it in something large enough to hold half of it.” Collins “fetched up a large breakfast cup, which held something less than half a pint”–that is, about 8 ounces. “Evans filled it about three parts full, and said, “Now, my boy, you must not sip this, it is bitter and nasty, you must drink it off at once.” Collins “took it from him, and drank it off at a draught– he had some bread and cheese, which he was eating for a lunch, and he eat some very hastily to take the taste out.” Evans left Burbridge’s house with instructions that the boy should have another cup with the same amount if the “stuff,” as Burbridge referred to it, hadn’t “taken its effect.”

Sadly, the “stuff” had already taken a most lethal effect. Collins quickly became very ill, showing all the symptoms related by Christison: nonstop vomiting, giddiness, pulsation in the head. A surgeon was called, and so were his parents, but there was nothing to be done. Camp Collins died about 10:30 that night.

A postmortem examination was performed on his cadaver, and none of the four surgeons present had any doubt that the foxglove was the cause. Nor was there any lack of certainty as to the party responsible. But certainty in law is not the same as certainty in science: the judge ruled that, under the statute for manslaughter, Evans could not be prosecuted. Evans had been called to the case by Collins’ parents. Moreover, he had never made any secret of his use of foxglove, but instead had written about it in his book. Negligent he may have been in a moral sense, but not in a criminal one. The jury brought in a verdict of “not guilty.”

On Wednesday October 9 at 7 p.m. EDT Lisa Rosner will be discussing forensics live on #HistChem's “Digging Up the Bodies: Debunking CSI and Other Forensics Myths.” Watch the live webcast at


Lisa Rosner is the Distinguished Professor of History at Stockton College and the author of The Anatomy Murders.

Information about Jacob Evans and Camp Collins comes from The Proceedings of the Old Bailey Online.

Robert Christison’s A Treatise on Poisons can be found at Google Books. 


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