During a recent talk on the relation between the body and the mind, I mentioned the newest anxiety-relieving craze, colouring books. Aimed at adults, these feature intricate patterns that provide quite a challenge for staying inside the lines. The contention is that focusing on the special patterns distracts the mind from anxiety and stress. Evidence is sketchy, but millions of colouring books are flying off the shelves, topping best-seller lists. That in itself says something about our society.
After my talk I was approached by a lady who claimed she had something better than colouring books to relieve anxiety and slipped a vial full of pills into my hand. She didn’t seem like a clandestine drug pusher so I thought I would look down and find some pills of lorezapam or maybe St. John’s Wort. Such was not the case. The label on the vial read “Arsenicum album 30C.”
No, she was not trying to poison me. These were homeopathic arsenic pills based on the curious notion that a substance that in large doses causes certain symptoms can, in homeopathic potency, repel the same symptoms. Since arsenic poisoning is associated with anxiety and restlessness, a person suffering such symptoms should find relief in a homeopathic dose of arsenic. In the bizarre world of homeopathy, potency increases with greater dilution, and a dose of 30C is said to be extremely potent. Such a pill is made by sequentially diluting a solution of arsenic a hundred fold thirty times and then impregnating a sugar pill with a drop of the final solution. At a dilution of 30C, not only is there no trace of arsenic left, there isn’t even a water molecule that has ever encountered any of the original arsenic.
Homeopathy is a scientifically bankrupt practice that was invented over two hundred years ago by German physician Samuel Hahnemann who was disenchanted with bloodletting and purging, common medical procedures at the time. He was a good man who searched for kinder and gentler treatments and homeopathy fit that rubric. Since knowledge of molecules was almost non-existent at the time, Hahnemann could not have realized that his diluted solutions contained nothing. Actually, the truth is that they did contain something. A hefty dose of placebo!
Now here is the kicker to this story. Hahnemann was quite accomplished in chemistry and actually developed the first chemical test for arsenic. In 1787 he found that arsenic in an unknown sample was converted to an insoluble yellow precipitate of arsenic trisulfide on treatment with hydrogen sulfide gas. When in 1832 John Bodle in England was accused of poisoning his grandfather by putting arsenic in his coffee, John Marsh, a chemist at the Royal Arsenal, was asked to test a sample of the coffee. While he was able to detect arsenic in the coffee using Hahnemann’s test, the experiment could not be reproduced to the satisfaction of the jury and Bodle was acquitted. Knowing that he could not be tried for the same crime again, he later admitted to killing his grandfather.
The confession infuriated Marsh and motivated him to develop a better test for arsenic. By 1836 he had discovered that treating a sample of body fluid or tissue with zinc and an acid converted any arsenic to arsine gas, AsH3, which could then be passed through a flame to yield metallic arsenic and water. The arsenic would then form a silvery-black deposit on a cold ceramic bowl held in the jet of the flame and the amount of arsenic in the original sample could be determined by comparing the intensity of the deposit with that produced with known amounts of arsenic.
The Marsh test received a great deal of publicity in 1840 when Marie LaFarge in France was accused of murdering her husband by putting arsenic into his food. Marie was known to have bought arsenic from a local chemist which she claimed was to kill rats that had infested the house. A maid swore that she has seen her mistress pour a white powder into her husband’s drink and Marie had also sent a cake to her husband who was travelling on business just prior to his becoming ill. The dead husband’s family suspected that Marie had poisoned him and somehow got hold of remnants of food to which she had supposedly added arsenic. The Marsh test revealed the presence of arsenic in the food and in a sample of egg nog, but when the victim’s body was exhumed the investigating chemist was unable to detect arsenic.
To help prove Marie’s innocence by corroborating the results of the investigation of the exhumed body, the defense enlisted Mathieu Orfila, a chemist acknowledged to be an authority on the Marsh test. Much to the defense’s chagrin, Orfila showed that the test had been carried out incorrectly and used the Marsh test to conclusively prove the presence of arsenic in LaFarge’s exhumed body. Marie was found guilty and sentenced to life in prison. The controversial case captured the imagination of the public and was closely followed through newspaper accounts making Marie LeFarge into a celebrity. It would also go down in the annals of history as the first case in which a conviction was secured based on direct forensic toxicological evidence. Because of Mathieu Orfila’s role in the case, he is often deemed to be the “founder of the science of toxicology.” The Marsh test became the subject of everyday conversations and even became a popular demonstration at fairgrounds and in public lectures. This had an interesting spin off. Poisonings by arsenic decreased significantly since the existence of a proven, reliable test served as a deterrent.
As far as claims about relieving anxiety with homeopathic arsenic go, well, they cause me anxiety. I think I’ll flush those homeopathic tablets down the drain (no worry about arsenic pollution here) and buy a colouring book.Â
