by Burch, Druin
Ninth-century Baghdad was the world’s most cultured city, as well as the largest. Greek medical texts were translated into Arabic, sponsoring both a reverence for ancient knowledge and a fresh interest in adding to it. Abu Bakr Muhammad ibn Zakariyya al-Razi, otherwise known as Rhazes, began studying medicine seriously only in his thirties, around the end of the century. He describes one of the first very deliberate comparisons of two alternative treatments among a group of similar patients:
When the dullness and the pain in the head and neck continue for three and four and five days or more, and the vision shuns light, and watering of the eyes is abundant, yawning and stretching are great, insomnia is severe, and extreme exhaustion occurs, then the patient after that will progress to meningitis . . . So when you see these symptoms, then proceed with bloodletting. For I once saved one group by it, while I intentionally neglected another group. By doing that, I wished to reach a conclusion. And so all of these contracted meningitis.
Confusingly, Rhazes is describing a group of patients who already exhibit the symptoms of meningitis. With the covering of their central nervous system inflamed, they cannot move their necks without painfully stretching their spinal cord. The light hurts their retina, the exposed (and now sensitive) portion of brain at the back of the eye. They are affected so badly that their consciousness has been clouded, the yawning and the stretching replacing the brain’s normal functioning. Rhazes is talking about a group of critically sick patients: the ones that he bleeds recover, the others do not.
Methodologically, he has made a step that verges on being brilliant. Comparing patients from two identical groups, then testing one strategy on some and a different one on the others, is exactly the way of telling the difference between the effects of luck and a treatment. Yet Rhazes reaches the wrong conclusion. Meningitis is a swelling of the meninges, the membrane covering the brain and spinal cord. Bacteria and viruses can cause meningitis, as can tuberculosis and trauma. Nothing that causes meningitis benefits from blood-letting.
Rhazes does not describe how he chooses to divide his patients up. Since he was a prominent translator of Galen, we know that Rhazes’s belief in blood-letting was profound. Were the patients he ‘intentionally neglected’ already sicker to start with, less promising for someone who wanted to show that blood-letting worked? Did he look after those whom he bled more carefully, or did they themselves feel encouraged by the treatment? How many patients were in the two groups? Given that some people with meningitis recover, and some die, were there enough to make sure that a run of luck did not distort his results?
Rhazes not only reached the wrong conclusion, he was also not particularly taken with his methods. The promise of his technique did not strike him as anything special. If it had contradicted his prejudice, and showed that those who were not bled did best, perhaps it might have pricked him into taking more notice. Rhazes showed some understanding of the power of comparisons, but in such a clumsy way as to make his example useless. We can see it as a flicker of mental development, a glimpse of something that could change the world – but not yet the real thing.
Rhazes had studied medicine in Baghdad, but he was born in Rayy, an ancient city that once dominated nearby Tehran and has now been absorbed within it. A generation later, another doctor from Rayy was innovating again, pursuing the idea that knowledge must be approached in a methodical way. Ibn Hindu (Abu al-Faraj Ali ibn al-Husayn) wrote that a doctor could gain knowledge in a number of ways. It could come as an accident, a natural experiment, something that you only needed to pay attention to in order to profit from. He gave the example of a boy who ate a laurel seed and then, being bitten by a snake, did not suffer. He felt that this was enough to demonstrate the protective properties of the seed. Alternatively, knowledge could be sought quite deliberately, ‘by making experiments with a purpose in mind’. You could do this by ‘trying several medicines one by one on bodies with different natures, time after time’. He did this himself, establishing to his own satisfaction that a plant known for causing diarrhoea could get rid of an excess of yellow bile, while another similar one got rid of black bile.
The problem was that his philosophy went nowhere. He was right that nature sometimes threw up circumstances which could teach you things, but wrong in his presumption that he could differentiate them from coincidences. Eating a laurel seed does not protect you from snake bite. Equally the idea of repeatedly trialling a drug until you could see what it did was a good one, but Ibn Hindu did not know how to do it. Both of the plants he talked of were perfectly good at causing diarrhoea, but the notion that they got rid of black or yellow bile – even the idea that the body actually contained these things in the way he imagined – was mistaken.
Ibn Hindu stressed the need for aspiring physicians to begin their studies with a thorough training in logic. It did not prevent his being unable to distinguish coincidence from causality, or from experimenting in such a crude way that he saw what he wished to see rather than what was actually occurring. Without the right methods even the most intelligent and well-meaning of scholars could be misled.
In the same century, other efforts to think about the proper way of testing treatments brought similar same mistakes. The first government-sponsored index of medical treatments was published in China in 1061. It consisted of around a thousand supposedly effective drugs. Although the original, all twenty-one volumes of it, is lost, many of the entries survive. According to one of these:
It was said that in order to evaluate the effect of genuine Shangdang ginseng, two persons were asked to run together. One was given the ginseng while the other ran without. After running for approximately three to five li [about a mile] the one without the ginseng developed severe shortness of breath, while the one who took the ginseng breathed evenly and smoothly.
It is the sort of story that sounds convincing. It remains, however, just a story. The trialists and the author mistake the satisfaction of having done an experiment with that of having done a reliable one. It is easy to imagine a host of reasons why one runner might have done better than another in a single trial. But recommendations acquire strength the moment they seem official, or become backed up by reputation or tradition. Beliefs cement themselves in human minds, and getting them out again can be exceedingly difficult.
One belief that people did manage to free themselves of through observation was the use of boiling oil in the treatment of gunshot wounds. Medical opinion in the early sixteenth century was convinced that this was greatly in a patient’s interest. Quoted in Donaldson’s translation, here is Giovanni da Vigo, surgeon to Pope Julius II, whose surgical textbooks became the standard works from 1514 onwards:
We have said . . . that the claws and teeth of beasts are venomous and that wounds made by firearms are infected with venom because of the powder and the treatment of the said wounds does not differ greatly. To come quickly to the treatment: if the wound is made by a horse, by a monkey or by a dog, or by a similar beast and given that the wound is large: one must cauterize the place with oil of elderberry with which should be mixed a little tiriaca galeni [treacle]. And, for wounds made by firearms it suffices to cauterize the place with oil of elderberry or with linseed oil . . .
Ambroise Paré was twenty-seven when he left his Parisian training and went to war. The French armies of François I marched against those of Charles V, the Holy Roman Emperor, and in 1537 Paré joined the French forces as the two armies met near Turin. Here is what he later wrote:
Now, at that time I was very inexperienced because I had not yet seen the treatment of wounds made by the arquebus; it is true that I had read in the first book of Jean de Vigo about wounds in general, chapter 8, that wounds made by firearms are poisoned because of the powder and for their cure he commands that they be cauterized with oil of elderberry to which a little treacle should be added. Not to fail in the use of this burning oil and knowing that such treatment could be extremely painful for the wounded, I wanted to know before I used it how the oth
er surgeons carried out the first dressing; this they did by applying the said oil as nearly boiling as possible to the wounds so I plucked up courage to do likewise.
At last I ran out of oil and was constrained to apply a digestive made of egg yolk, oil of roses and turpentine. That night I could not sleep easily thinking that by the default in cautery I would find the wounded to whom I had failed to apply the said oil dead of poisoning; and this made me get up at first light to visit them. Beyond my hopes I found those on whom I had put the digestive dressing feeling little pain from their wounds which were not swollen or inflamed, and having spent quite a restful night. But the others, to whom the said oil had been applied, I found fevered, with great pain and swelling around their wounds.
‘Je le pansay; Dieu le guarit’, he later said. ‘I dressed the wound, God healed it.’
Paré, perhaps protected from dogmatism by his own ignorance of Greek and Latin, succeeded in noticing the results of his small natural experiment. It seems unlikely that Paré was the first battlefield surgeon to run out of oil before the end of a bloody day. The salve that he turned to was also one that he had learnt from Vigo’s book, but it was one that was meant to be applied some time later, when the wound was already healing. Paré’s achievement was to realise that the evidence provided to him by his experience was worth more than the teachings of the greatest known authority. It never occurred to him, though, to deliberately repeat the sort of trial he had blundered into inadvertently, and to test one approach against another intentionally. The thought that the egg yolk, rose oil and turpentine might also be bad for wounds never came to him. (In fact, the dressing was specifically designed to make sure the wound grew infected. The pus of infected wounds was so universal in those unsterile times – appearing without fail as though no wound could mend without it – that doctors believed it was essential for healing.) The closest Paré came to a deliberate trial was when an old woman told him that onion ground up with salt made a good dressing for burns, and he gave it a try:
Some time later a German of the guard of the said seigneur de Montejan [the French infantry commander] was very drunk and his [gunpowder] flask caught fire and caused great damage to his hands and face, and I was called to dress him. I applied onions to one half of his face and the usual remedies to the other. At the second dressing I found the side where I had applied the onions to have no blisters nor scarring and the other side to be all blistered; and so I planned to write about the effects of these onions.
Even today, almost five hundred years after Paré struggled to improve the surgical treatments available to him, it is difficult to keep mentally distinct his unusual successes and his completely ordinary failures. To say he was ‘experimenting’ with wound dressings implies that he did so in such a way as to be able to tell the difference between what worked and what did not. Since his efforts were not reliable enough to do that, in a sense he was not ‘experimenting’ at all – he was tinkering, fiddling, messing around, engaged in activities that were fundamentally frivolous in terms of the risks they took with another person’s health. As a single attempt, the onions on one part of the face told him nothing. Some wounds heal well, others badly. Infection sometimes strikes here and not there. Only a more methodical and repeated approach could have revealed to Paré if his ground onions held the power to heal.
Our ideas about science have developed, while the words we use to describe them often contain the muddles of half a millennium ago. It would have been better, much better, if the word ‘experiment’ had come, very strictly, to mean only something capable of identifying mistakes and illusions.
John Baptista Van Helmont’s book Oriatrike, or Physick Refined was published in English in London in 1662, declaring, as textbooks are wont to do, that it set everything right that had been wrong. The book’s modest subtitle was: ‘The common ERRORS therein REFUTED and the whole ART Reformed & Rectified’. It contained sentiment and imagination of a biblical tendency, both in the style of its prose and the power of its meaning:
For Medicine is not a naked word, a vain boasting, or vain talk, for it leaves a work behind it: Wherefore I despise reproaches, the boastings, and miserable vanities of ambition: Go to, return with me to the purpose: If ye speak truth, Oh ye Schools, that ye can cure any kind of Fevers without evacuation [i.e. using drugs to make people release the contents of their bowels or stomachs], but will not for fear of a worse relapse; come down to the contest ye Humorists [followers of Galen]: Let us take out of the Hospitals, out of the Camps, or from elsewhere, 200, or 500 poor People, that have Fevers, Pleurisies etc. Let us divide them in halves, let us cast lots, that one half of them may fall to my share, and the other to yours; I will cure them without blood-letting and sensible evacuation; but do you do, as ye know . . . we shall see how many Funerals both of us shall have . . .
Unfortunately Van Helmont’s strong feelings spent themselves in his words. Had he put in practice the trial that he preached, the world might have changed. Not only might doctors have discovered the harm that they were doing – the evils of taking sick people and bleeding them, giving them diarrhoea or making them vomit – but they might have realised that Van Helmont’s technique could help them discover treatments that actually helped. Instead Van Helmont was content with making only a mental experiment, vindicating his ideas to himself only in his own imagination and his bombastic prose. Given that those reading his text could perform the same mental experiment – and, in their own heads, satisfy themselves that their patients survived better – Van Helmont persuaded no one. His medicine remained a naked word, and a vain talk, and left no work behind it. The next century, however, was to do better.
5 The Taste of Trees
OPIUM WAS NOT the only drug that eased pain. It was probably not even the commonest. That was alcohol, and it was often more popular with doctors too. The concentration of opium was difficult to predict, and dosing someone by mouth was unreliable. By the time the doctor produced the sedative effect he wanted, the patient might still have a stomach full of the stuff, steadily tipping them beyond peacefulness and into comatose oblivion. Alcohol was less inclined to put people permanently to sleep.
Beyond those two, before the mid-eighteenth century, there was not much else. Cloves had some mild powers, but their cost wasn’t matched by their effectiveness. Sugar could help a little. The Jewish practice of giving a baby a teaspoon of sugared wine before a circumcision has been shown to be a significant help – but, unsurprisingly, not a complete one. Edward Stone, born in 1702 to a farming family in Princes Risborough, a town in the Chiltern hills between Oxford and London, was the man who changed things. He went to Oxford at the age of eighteen, before entering the Church. From 1745 he was based in west Oxfordshire, living in the town of Chipping Norton and serving as chaplain to Sir Jonathon Cope at the small village of Breurn. Sometime around 1757, on a walk through the Cotswold countryside, he fell upon an idea.
It began with something that Stone never quite explained. Willow trees grew along the riverbanks, in the fields where he walked. One day he took a piece of bark and put it into his mouth. ‘I accidentally tasted it,’ he said, rather as though he had tripped over something. Willow bark, Stone discovered, did not have the sweet warmth of cinnamon. In fact, it tasted pretty awful. It was horribly bitter, and it reminded the educated Reverend Stone of something – it reminded him of cinchona.
Looking back, he declared that what motivated him to investigate the bark further was ‘the general maxim, that many natural maladies carry their cures along with them, or . . . their remedies lie not far from their causes’. It was a way of thinking packed with unexamined superstition, and not far from the doctrine of signatures that had enthralled Paracelsus and many others. The coincidence of nettles growing alongside the dock leaves that ease their sting was widely noted; the lack of other examples across the breadth of human maladies was overlooked. The Reverend Stone was a firm believer in the Bible and the Church of England. That did not stop him from also ho
lding a few beliefs that were more akin to pagan magic.
Stone reasoned that since malaria was very common in the marshy places where willow grew, it was likely that the tree would cure the disease. That, at least, was how he explained himself six years later. He may have been trying to create a meaningful narrative to impress his audience at the Royal Society. Regardless, it is significant that Stone chose to justify his actions in the way that he did. Technology had developed hugely between early human civilisations and eighteenth-century Oxfordshire: ways of thinking about the world had not necessarily followed.
Seeking to investigate whether willow could be as useful as cinchona, Stone collected the bark one summer, then put it in a bag near a baker’s oven. Three months later it was dry enough to be pounded into powder. With malaria common around Chipping Norton, the Reverend began treating people with his new powder. It seemed to work – when he gave it to people, he felt that their fevers went down and that they went on to recover. Whether they would have done so anyway, and possibly sooner if he had left them in peace, did not occur to him. For five more years the Reverend Stone continued to dose the malarial residents of Chipping Norton, before screwing up his courage to write to the Royal Society.
His bark, he said, ‘hath been given I believe to fifty persons, and never failed in the cure, except in a few autumnal and quartan agues’. It was exactly the sort of reasoning that Galen had used, describing his remedy that cured absolutely everyone – except for those who died, who must therefore have been incurable.
Cinchona bark had originally been substituted for Peruvian balsam as a way of saving money. It was only good fortune that cinchona turned out, not only to reduce fevers as the balsam had done, but actually to cure malaria. Now Stone had come up with a new money-saving option. Rather than import expensive cinchona from Peru, Englishmen could gather a cheap alternative.