Prefiguring the Arsenic Wars

David S. Caudill

In his article Jackson detailed the ambiguous results of the various liquid tests performed by the board of physicians, noting that the comparison of “colours is extremely difficult” and that “even experienced eyes may be deceived.” The board had used four tests to detect arsenic in Logan’s body. First, the board performed a “sulphus cupri” test, boiling fluid from Logan’s stomach with a few grains of the sub-carbonate of potash; the fluid turned light green when copper salt was added. In the second test, the physicians placed a sample of stomach fluid on white paper and drew a stick of silver nitrate over it, causing the spot of fluid to turn pale yellow. For their third test, the board placed a small quantity of the dried stomach between two plates of copper coated with black flux (a paste of potassium salts of boron and fluorine); the plates were then heated to produce a silvery white stain. In their fourth test, the physicians passed a stream of sulphuretted hydrogen through a sample of stomach fluid that had been boiled and cooled; this process caused the sample to turn yellow. While the board concluded that the four results revealed the presence of arsenic in Logan’s body, Jackson questioned the board’s application of the tests. He noted that the “sulphus cupri” test could detect arsenic but also “other matters which are sometimes found in the stomach”; that “the copper and silver tests were used in the most objectionable forms”; and that the sulphuretted hydrogen test might have allowed tartar emetic, which Jackson had administered to Logan before his death, to be mistaken for arsenic.

Jackson argued that the physicians’ failures in chemical experimentation meant that there was no proof of the presence of arsenic. “They leave us destitute of all positive proof, and greatly debilitate the circumstantial; therefore, since such strong suspicions arose in their minds, it is greatly to be regretted that they did not proceed further with the enquiry.” Moreover, Jackson continued, some “important leading tests were omitted”—no microscope was used, although “a very powerful one was within their reach,” and no drawings of the later destroyed stomach were made, although “some excellent delineators were at hand.” How could all these misjudgments be explained?

The answer, for Jackson, was hubris. He did not blame the physicians for jumping to conclusions or for performing half-hearted chemical experiments. Instead he blamed the hubris of John Ayrton Paris, a well-known Edinburgh physician who was the subject of harsh criticism from other scientists as well as Jackson. Paris’s pharmacological treatise, Medical Jurisprudence (London, 1823), coauthored with lawyer John Samuel Martin Fonblanque, was the main resource on which the board of Logan’s examiners had relied.

The physicians believed, as Paris promised, that the copper and silver tests were infallible. This belief, Jackson argued, was at the root of their folly.

Dr. Paris is so delighted with making these arsenical colours, that, while writing on the subject, he has laid down his pen to “convince himself with how little trouble, and with how much pleasure and profit, such experiments may be conducted.” . . . If this be not mere childish play, it is at least the extravagance of a man transported with novelties. . . . Does not everyone perceive how much room there is left for the ardent imagination of a man zealous in the pursuit, to play on these colours[?]

For Jackson the colors from all the board’s tests provided “one degree of evidence only.” More conclusive evidence could have been produced by experimenting on a metal extracted from the precipate—if there was enough precipate to undergo metallization. Without the results of such an experiment, Jackson argued, the board could only assume the presence of arsenic in the deceased’s body. The hubris and ethical lassitude of Paris’s treatise had left the board of physicians in the Logan case “like mariners in an ocean to them unknown, the rocks and shoals of which were left unnoted in their only chart.” Following Jackson’s critical appraisal of the board of physicians’ report and notwithstanding the board’s sworn testimony that Logan died from arsenic poisoning (and no testimony in Mrs. Logan’s favor), the grand jury acquitted Mrs. Logan by a vote of 23 to 1.

Jackson’s concerns about incompetent “expertise” were not unique. Just two years earlier in England, in an 1826 trial in Sussex, Hannah Russel and a lodger in her home were accused of poisoning her husband. Evidence that she had purchased arsenic, together with the testimony of a local surgeon who said he found arsenic in the victim’s stomach, resulted in convictions. The lodger was hanged, but Russel’s execution was delayed. Gideon Mantell, a Sussex physician and geologist, took an interest in the story. Convinced that the deceased—who had experienced heart problems—had not been poisoned, Mantell criticized the surgeon’s tests and sought confirmation of his views from other physicians. When Russel was pardoned, the pattern of overconfident experts, later corrected by those with better procedures or credentials, was firmly established. Such disagreements, in the Logan and Russel cases, prefigured what would come to be known as the “arsenic wars.”