The Pharmaceutical Journal
Vol 271 No 7276 p724
22 November 2003

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Beautiful bane [more]
Tracking the SARS virus [more]
Truth and falsehood [more]

Beautiful bane

During late summer there was much controversy in my local press regarding the peril which the common ragwort (Senecio jacobaea) presents to grazing cattle and, particularly, to browsing horses in fields where it becomes exuberant. Much ill-informed criticism of the plant comes from horse-owners who, I find, are highly sensitive to anything that can be made out to threaten the welfare of their beasts. All species of Senecio contain pyrrolizidine alkaloids that have toxic effects on liver, kidney and lung if consumed in significant quantities. In fact, grazing animals will not touch the growing plant unless denied their more usual fare of grass, and its main hazard is derived from its dying down and becoming dry, when it appears that its attraction is increased. Sheep can consume moderate amounts without apparent harm.

An area of waste grassland presents a beautiful site when it nourishes a crop of ragwort. The 19th century Cambridgeshire poet John Clare wrote in 1831: “Ragwort, thou humble flower with tattered leaves, / I love to see thee come and litter gold . . . / Thy waste of shining blossoms richly shields / The sun-tanned sward in splendid hues that burn.”

And Lady Vyvyan in her book ‘Our Cornwall’ (1948) called it “perhaps the most beautiful of all the August golden flowers”, although she went on to admit: “It is the bane of farmers, for it is ubiquitous; it will gleam in a green hedge and cover the nakedness of a quarry, and take possession of ditch and field, and make encroachments on a garden.” Yet a farmer in the West Country in 1993 picked his ragwort in flower and sold it in his farm shop as “summer gold” to the delight of visiting townspeople. In the Isle of Man, ragwort is the national flower and is known as cushag.

After the battle of Culloden in 1746 the victors named a fragrant garden flower (Dianthus barbatus) “Sweet William” in honour of their general the Duke of Cumberland. The Scots retaliated by calling the wild ragwort “Stinking Willie”. Other vernacular names given to it are staggerwort, yellow-tops and, because it was supposed to be a remedy for speech defects, stammerwort. It was supposed to be used among the fairies of Celtic culture as a vehicle for transit, and in the 16th and 17th centuries ragwort stalks were one means whereby witches flew to sabbaths. Despite this, in some countries ragwort was called herba sancti Jacobi, the herb of St James, since it was in full blossom on his feast day, 25 July.

In folk medicine, ragwort leaves were used in poultices for irritant skin conditions. The juice is astringent and was applied to burns and ulcers. A decoction of the flowers was used to dye wool yellow.

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Tracking the SARS virus

So far, the reservoir of infection from which severe acute respiratory syndrome has affected humans is not known with any accuracy. The coronavirus involved, or one closely allied to it, has indeed been claimed to occur in the Chinese ferret, the badger, the masked palm civet, the raccoon dog and the domestic cat.

In the 30 October issue of Nature, investigators from China and the Netherlands described experiments to determine the susceptibility of ferrets and cats to intrathecal injections of the virus derived from a patient with SARS.

No clinical signs of the disease were observed in treated cats, whereas three of six ferrets became lethargic from two to four days after the injection and one of them died on the fourth day. Both species shed the coronavirus from the pharynx after two days — until day 10 for cats and day 14 for ferrets. All the animals showed respiratory tract infection and the virus could be isolated from trachea and lungs. Moreover, it was detected in the gastrointestinal and urinary tracts. Non-inoculated cats and ferrets housed with the inoculated counterparts became infected with the virus, with its titre increasing after two days and then peaking after six to eight days, but cats did not show clinical signs. On the other hand, two ferrets became lethargic and developed conjunctivitis, dying after 16 and 21 days. The main lesions found in them were marked liver lipidosis and emaciation. There was no evidence that either of the ferrets involved died from virus-associated pneumonia, although in one of them virus was isolated from a lung sample.

These results indicate that ferrets and domestic cats might prove useful in testing the effects of antiviral drugs or vaccines on the SARS coronavirus.

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Truth and falsehood

One of the fascinating books on my library shelves is ‘Straight and crooked thinking’ by Robert H. Thouless, and now and then I feel inclined to look into it once again. It is antique by modern standards, having originally been published in September 1930.

Thouless tells us in his preface: “It is not necessary for a writer on crooked thinking to make the essentially dishonest claim (based on prestige suggestion) that he himself is a model of straight thinking. We can only understand crooked thinking when we have followed it in our own minds as well as in the writings and speeches of others.”

To begin, we need to have care in making definitions of what we mean when we use certain words. As Francis Bacon commented in his essay “Of truth” in 1625: “What is truth? said jesting Pilate, and would not stay for an answer.” Many have availed themselves of this let-out since Pilate’s time.

Thouless observes that we should look out for the difference between the strictly objective and the emotional, and that words carrying a weight of emotional attitudes are commonly employed on controversial discussions of politics, morals and religion. In place of the word “firm” used of ourselves, we can say “obstinate” of someone else or “pig-headed” of another; all have the same objective meaning but differ in emotional reaction. We attribute bad temper to a red-headed individual almost instinctively, although the two do not always go together, and we are never justified in drawing a general conclusion from a single instance. What is known as “tabloid thinking” is nevertheless, argues Thouless, practically useful, although it is a hindrance to straight thinking. But we cannot tolerate it if our objective is truth.

When we encounter politicians today we often detect their essential dishonesty when they make pronouncements or justify decision. Thouless offers us a list of 34 dishonest tricks commonly used in argument, with methods of overcoming them. Among them are emotionally toned words, extension of the particular into the general, selection between facts, sheer misrepresentation or diversion, choice of a mean between extremes, repeated affirmation or confident presentation, backed by prestige or false credentials, and use of pseudo-technical jargon. Add to these the regular practice of false analogies and you will find yourself lamentably astray from the road to objective truth, to which scientists in particular ought to remain faithful.

It might be as well to remember the old legal phrase “the truth and nothing but the truth” is impossible to achieve. Who can ever know how much of the total truth has never been brought to light?

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