THE FOLLOWING ARTICLE APPEARED IN THE

FEBRUARY 1997 ISSUE

THE POISON SLEUTHS

ARSENIC - THE KING OF POISONS

-Dr. Anil Aggrawal

"Good morning doctor. Oh, my God, what are you doing with this dead body? He seems to have a terrible rash all over his body. Would you explain me what he died of?"

"Good morning Tarun. This man is Radheyshyam who is a 56 year old man. His first wife died about 5 years back, and soon after he married again. He was complaining of loose motions and vomiting off an on for the last two years. The doctors suspected he was suffering from gastroenteritis, which as you know is an inflammation of the stomach and intestines. But what they could not find out was the cause of this inflammation. Consequently he was being given only the symptomatic treatment. Finally he succumbed yesterday to his illness."

"Then why is he here? Why haven't his relatives taken him for cremation. You are a forensic pathologist, and if I understand it correctly, you only look after cases with legal implications. What possible legal implication could be involved in this case."

"You are right Tarun. I deal only with legal cases. But yesterday, the brother of this person, Harishyam has alleged that his brother's relations with his new wife Shanti were not good. He suspects some foul play in his death. Many times he saw her mixing some whitish powder in his food. When he enquired, she would say it was some medicine she had brought from the local doctor for his illness. Immediately after his brother's death he reported the matter to the police. In response to his complaint, the police has registered a case against Shanti, and has submitted the body to me for post-mortem. Now my job is to find out if he really died of gastroenteritis."

"Doctor, it seems very confusing. Just now you said that he did die of gastroenteritis. His symptoms were that of gastroenteritis, and he was getting treatment for it. Then what else could he die of?"

"On the face of it, it does appear that he died of gastroenteritis, but there could be foul play as well. You yourself remarked over the rash he has all over the body. Well, in gastroenteritis one does not get rash over the body."

"Then he might be having some concomitant skin disease, isn't it?"

"Could be. But a more likely explanation could be arsenic poisoning, especially as Harishyam repeatedly saw Shanti mixing some white powder in his brother's food."

"You mean Shanti was giving him arsenic, because of which he developed gastro-enteritis like symptoms and also the rash?"

"Yes, that's what I mean Tarun. But I must tell you that pure metallic arsenic is seldom poisonous. It is its white colored salt Arsenious oxide, known in the vernacular as Sankhya or Somalkhar which is poisonous. It is this salt which is often loosely referred to as arsenic. When a chemist talks of arsenic, it is the pure arsenic, but when a toxicologist or a pathologist like me talks of arsenic, he is probably referring to arsenious oxide. We sometimes refer to it as white arsenic also, because of its white color"

"Arsenic certainly seems an interesting poison. Please tell me more about it doctor."

"Tarun, arsenic is a metallic poison known since ancient times. An eighth century Arab alchemist Geber produced arsenious oxide, from realgar, a naturally occurring red colored ore of arsenic found in lead and iron mining, and thus made available to the humanity one of the most cruel, deadly and widely administered poisons. In Imperial Rome a form of arsenic was used as a poison to such an extent, that kings, queens, and other important court officials regularly employed official food-tasters! It has been a favorite with the poisoners because it fulfills many of the criteria of an ideal homicidal poison..."

"I beg your pardon? Do you mean to say that there are things like ideal homicidal poisons? What in the world does this term mean? How can anything as sinister as poison be ideal?"

"Tarun, there not only are ideal homicidal poisons, but ideal suicidal poisons too. You see, there are several poisons in this world, but not all can be used homicidally or for suicide. Only certain poisons are ideally suited for these purposes. Poisons which suit well for these purposes are known as ideal poisons."

"It is still not very clear to me. Would you please explain with some examples?"

"Sure. Let us talk about homicidal poisons first. A bitter poison, like strychnine, can obviously not be given with homicidal intent. The victim would immediately spit it out. Thus a homicidal poison must be tasteless. Similarly a poison which is colored can not be given. Copper sulphate is poisonous, but it is blue colored. If a killer mixes it in water or milk, it will render these liquids blue, and the victim would not drink it. Thus a homicidal poison should be colorless too. There are several other criteria which have to be fulfilled as well before a poison qualifies as an ideal homicidal poison. It should be easily available, fatal in only a small quantity and symptoms of both acute and chronic poisoning must mimic natural diseases..."

"Why should this be so?"

"Because then the public at large would think that the person died of that natural disease whose symptoms the poisoning mimics, and the killer would go scot free. Arsenic qualifies well in all the above criteria. Symptoms due to its poisoning mimic natural diseases. While acute arsenic poisoning resembles gastro-enteritis, chronic arsenic poisoning presents a combined picture of stomach upsets, peripheral neuritis and dermatitis..."

"Sorry to interrupt you doctor. You have introduced some new terms which I don't understand. What in the world is meant by acute and chronic arsenic poisoning?"

"Tarun when a large dose of a poison is given in one go, killing the victim within minutes, it is called acute poisoning. On the other hand when small doses of a poison are given over a long period of time, typically over years, it is called chronic poisoning. If a wife wants to kill her husband, it would be very easy for her to mix sublethal doses of a poison in his food over a long period of time. By sublethal dose, I mean a quantity of poison which is not enough to kill the victim in one dose. The hapless husband would die in the end after a few years. In this case he would be said to have died of chronic poisoning."

"oh, I see. So you were telling me about the criteria of an ideal homicidal poison."

"Yes, I was telling you that the effects of arsenic poisoning resemble natural diseases. Its effects are cumulative, so the poisoner does not have to rely on one large, fatal dose; he can give it little and often, thereby weakening his victim by stages before delivering the fatal dose. An ideal homicidal poison should be undetectable in the dead body. About one and a half century back, arsenic fulfilled this criteria as well, but no more now. Before 1836, it was impossible to detect it in the body organs. All these facts made it the poisoner's ideal choice. So commonly and successfully was it used for homicidal poisoning that once it was variously referred to as king of poisons or poison of poisons. Since many people used it to do away with rich old uncles and aunts, it became known in France as poudre de succession, or "inheritance powder". The history of crime is replete with cases of homicidal poisonings by arsenic. Arsenic was ostensibly bought for killing rats, but it was often used for homicidal purposes. Women purchased it to kill rats; the rat in most cases used to be the husband!"

"Funny joke! What about ideal suicidal poisons?"

"A person who is going to commit suicide with poison, probably wouldn't worry about its color or even taste. He wouldn't be bothered with taking large doses too. He would be more concerned about the pain the poison is likely to produce. He needs a poison which produces minimum discomfort, and produces death or at least sleep within minutes, so his agony is lessened. Sulfuric acid is a deadly poison, but it would kill rather slowly; in about 12-24 hours. Moreover it is a strong corrosive producing severe burning pain in the mouth and throat. A potential suicide may be interested in death, but he probably wants a quieter death. So Sulfuric acid is not an ideal suicidal poison. Barbiturates or sleeping pills on the other hand are ideal suicidal poisons, because they would put a person rapidly to sleep, and then to death. There are no unpleasant symptoms."

"Oh I see. While talking about arsenic you mentioned the year 1836. What happened in that year?"

"In that year a successful test for arsenic was developed for the first time. It was called the Marsh test and it ultimately brought about its downfall as an extremely successful homicidal poison. One quality of arsenic makes it a very poor candidate as a homicidal poison; it can be detected in the dead body, virtually years after the body has been buried. Thus the poisoner leaves a permanent record of his deed in the dead body...

"But how can anyone detect the poison in the body, once it has been buried?"

"There are laws in all countries which allow the law enforcement agencies to unearth or exhume the body, if strong suspicion develops against some person later on. There have been cases where the bodies have been exhumed as late as 3-4 years after death, and arsenic has been detected in their bones. An ideal homicidal poison should immediately disintegrate after doing its job. Before 1836, this peculiar property of arsenic did not cause any problems to the poisoners because there was no test for arsenic in the first place. With the development of Marsh test, this property assumed paramount importance and it rapidly fell into disfavor."

"So before the development of Marsh test, all the cases of poisoning must be going undetected?"

"Yes! Many celebrated cases are on record when the suspected poisoner went Scot Free merely because of the inability of the chemists of those times to detect it in a dead body. In fact tests weren't available for any poison. The only reliable test was to feed the remains of the poison to an animal and see if it died. So desperate was public that Henry Fielding (1707-1754), a celebrated English novelist clamored in despair for some way to make poison visible so that one could hang the poisoner. That was in the year 1740. This was in connection with a case in which a widow was accused by neighbors of having poisoned her husband. But no poison was found in the widow's house, nor could it be proved that she had ever purchased poison. The only thing left, therefore, was to show that the corpse had poison in it. When Fielding appealed to the doctors, they answered that there was no way to do this. The widow had to be acquitted"

"And then came the Marsh test"?

"Marsh test came much later. Many interesting things happened before that. One of the most celebrated cases of arsenic poisoning occurred in 1752, when a 31-year old spinster Mary Blandy murdered her father with arsenic. Her court appearance was the first trial for murder by poison at which medical evidence was called in regard to the cause of death. Dr. Anthony Addington did not possess the knowledge to analyze the victim's organs for poison, nor was he able to use chemical tests to prove that the powder Mary used was arsenic. Nevertheless, on the basis of simple comparison he convinced the court that the powder was arsenic, and Mary Blandy was convicted and sentenced to death."

"How were those comparisons made?"

"Mary Blandy mixed white arsenic in gruel and gave it to her father. She wanted to kill him, because he was not agreeing for her marriage with someone she loved. Two days after eating the gruel, Mr. Blandy fell seriously ill. Some of the gruel left over was eaten by the charwoman and she was violently sick too. A maid also ate some of it, and she also fell sick. Because of this peculiar chain of events, they became suspicious and examined the pan used to prepare the gruel and saw a white sediment at the bottom. They locked up the pan and next day handed it over to the doctor."

"And he compared that sediment with a known sample of arsenious oxide, and found them to be similar?"

"Exactly. In today's parlance they would be called physical tests. He believed the sediment on the pan to be white arsenic because it had a milky whiteness, it was gritty and almost insipid. When put in cold water, part of it swam on the surface, but the greater part sank to the bottom and remained there undissolved. Arsenious oxide behaves in exactly the same way. When thrown on red-hot iron it did not burn, but sublimated, i.e. it rose in thick white fumes. These fumes had the stench of garlic. To be sure he did perform some simple chemical tests but they were also comparative in nature. This means that he conducted some chemical tests both on the sediment and on a known sample of arsenious oxide, and both gave similar looking reactions. The court accepted these tests- the first time any court accepted a scientific evidence in a case of arsenic poisoning- and sentenced Mary Blandy to death."

"That certainly is interesting! I mean science ultimately catching up with the poisoners."

"Twenty-three years after Mary was hanged, in 1775, a Swedish chemist made an important discovery. Karl Wilhelm Scheele found that he could change arsenious oxide to arsenious acid by treating it with nitric acid. Arsenious acid in turn when treated with zinc produced arsine, a highly poisonous gas. This epoch making work had the germs from which a reasonably good test for arsenic could be developed. This work was actively pursued by scientists in Germany, but the break-through was provided by an English chemist James Marsh. In 1836, he published a method for converting arsenic in body tissues and fluids into arsine gas, which was quite similar to that of Scheele. But the interesting thing was that Marsh was able to convert arsine back to metallic arsenic which could be shown to the court. It is much easier for a non-technical person like a judge to convict a criminal when he can actually be shown the poison which killed the victim."

"How did Marsh convert arsine to metallic arsenic?"

"As the gas escaped, the gas was ignited, and Marsh held a cold porcelain bowl against the flame. The metallic arsenic precipitated on the porcelain in the form of a black deposit. The process was unbelievably sensitive, making it possible to detect as little as a fiftieth of a milligram of arsenic! The Marsh test revolutionized the investigation of poisoning, and it was quickly taken up by crime scientists."

"After the development of the Marsh test it must have become a lot easier for crime scientists to prove the presence of arsenic in a dead body?"

"Yes surely. In 1840, the Marsh test was used in the celebrated Lafarge poisoning case. In January of that year Charles Lafarge, a minor French industrialist, died of suspected poisoning at his home in Le Glandier. Arsenious acid was found in his stomach, and it became known that his wife, Marie, had bought arsenic as rat-poison. She was arrested and sent for trial. The application of new scientific methods proved futile at first. When the Marsh Test was applied to corroborate earlier findings of arsenic by traditional methods, the results proved negative. The defence was elated, but the elation was short-lived, as the experts declared that the test worked better on organs other than the stomach. Exhumation of Lafarge's body was carried out for the purpose of retrieving these other organs for testing. Famous French toxicologist Dr. Mathieu Orfila was summoned by the court. He applied the Marsh test correctly and found arsenic in Lafarge's body. This case stirred up so much controversy in France, that the entire country was divided into Pro-Marie and anti-Marie factions. The case ended up in Marie being delivered the sentence of life imprisonment. Marie served 10 years of sentence. She was released by Napoleon III in 1850, and she died the following year still declaring her innocence!

"Every killer does assert he is innocent. So arsenic has really been responsible for many killings. Good that the scientists ultimately came up with a good test for arsenic. Tell me doctor, what are your conclusions regarding this man Radheshyam?"

"When his body was brought to me, I immediately suspected chronic arsenic poisoning..."

"Really? What made you think so?"

"The fact that his relations were not good with his wife, and that he was complaining of loose motions and vomiting for the last two years. The doctors were not able to find out a cause for his gastroenteritis. This is a classic picture of chronic arsenic poisoning, when the wife is stealthily mixing it in her husband's food. To top it all, she was often seen mixing some white powder in his food. But what clinched the diagnosis was the examination of his dead body. I am now positive he died of chronic arsenic poisoning."

"How did you arrive at this conclusion?"

"One of the landmark symptoms of chronic arsenic poisoning are the skin changes. The most important skin changes are, first, pigmentation and second hyperkeratosis, which is nothing but a technical term for thickening of the skin. If arsenic is given continuously for some years, even skin cancer may develop. You yourself remarked on the rash this person has all over his body. This rash is nothing but pigmentation. As you can see, this is finely mottled, brown rash, presenting a picture as if colored rain drops splashed his body. In fact this rash is often called "raindrop rash". This rash resembles measles rash in many ways. You can also see that his palms and soles are thickened. This is the hyperkeratotic change, another classical sign of chronic arsenic poisoning. In fact, even if I hadn't been told anything, just this change would have brought arsenic poisoning to my mind. You can also see that he has an irregular thickening of nails which is another good sign of chronic arsenic poisoning. The final clinching fact was the chemical test. when I applied Marsh test to his internal organs like liver, spleen and kidneys, arsenic was found to be present in abnormally high amounts. It is certain that he died of chronic arsenic poisoning. Let us phone the police and tell them about it."

"Yes, certainly we should. Thank you doctor for giving me such interesting information on arsenic. What are you going to tell me the next time?"

"Tarun, next time I shall tell you about Spanish Fly, which as you shall see has acquired a very notorious reputation. "