Hell! Why don’t we just ban it altogether?After all, while it will make newspapers, magazines and commercial television much more expensive for the consumer, it will make them so much more indispensable. Without advertising, the only way to find out about what’s in the shops will be to read about it in the editorial pages or on the telly.And it will make absolutely everything else so much cheaper, since the money spent on the advertising of all products is passed on to us, the consumers. This can become ludicrous, as sometimes when you buy a product all you are really paying for is the advertising that persuaded you to buy it in the first place.The most striking example of this parasitical circle, designed to shaft the consumer from every direction, is in the perfume industry. Fashion houses increasingly make their money from beauty products rather than clothes, thus subsidising couture clothing for the rich by fleecing a far wider range of consumers. But they also get away with persuading us to pay vast amounts for a product it costs virtually nothing to make, simply because they spend so much money on advertising it that no publication will dare to expose quite the scale of the con that is being perpetrated. Any more than a whisper of criticism and the fashion houses rise up to withdraw all their advertising, thus bringing financial ruin to the hapless publication that dared to tell the truth.

It’s remarkable that the selling of pleasant fragrances can stink so much, but it does.Since the media is regularly compromised by such considerations, there is a genuine argument that advertising is in itself a threat to freedom of expression. This is not, however, a conclusion that the present Government is likely to be drawn towards. New Labour has an advertising budget considerably larger than that of any previous government. So it is safe to assume we’ll be sticking with a ban on tobacco ads alone for the foreseeable future. But it’s not so safe to assume that these therefore are the only products that are bad for your health and for the environment. They’re just the ones that get up people’s noses in a particularly obvious and noxious fashion..

“THE ULTIMATE Frankenstein bird has been created in the laboratory”. So crowed the Daily Express recently beneath the headline: “Now scientists serve up the 3-legged hen”, reporting hostility to the experiment from animal welfare campaigners, who said the research was an adult version of a child pulling the wings off insects. Such articles give undue prominence to pressure groups and do little to advance the relationship between scientists and public. But then, that is not the aim of the tabloids – they know that genetic pornography that titillates and shocks, sells papers. You can imagine their headline 60 years ago – “Dracula doctors do their bloody worst” – when blood transfusion was at last being successfully carried out. Does not taking blood from one person and putting it into another amount to playing God in a truly dangerous manner?
The limb experiment is unlikely to make a contribution to human health on the scale that blood transfusion has, but it tries to understand some basic biology, namely how we develop from a single cell, the fertilised egg.There are undoubtedly those among the pressure groups hostile to science who think that this is both unnecessary and dangerous. But those who wish to censor and stop such activities should come out and say so, and not shriek from behind a wall of high moral virtue from which they attack scientific advances with spurious arguments.The vertebrate limb has long been a good model for studying pattern formation in the developing embryo.

While the embryo generates lots of different cell types, such as blood, nerves and bone, it is how these are organised in space that makes us human beings, rather than hippopotamuses or chimpanzees. The limb has the advantage that its pattern is quite simple to observe in the early stages, the main feature being cartilaginous elements such as the humerus and the digits. Moreover, in the early chick embryo it is possible to manipulate the limb’s development and see the effects long before the time of hatching – at least a week.One of the ways pattern can be specified is by the cells knowing where they are in the limb and then developing in the right way; they have positional information, plus a set of instructions in the genes on how to interpret their position in terms of cell behaviours. The cells acquire positional identity as the limb grows out, and it has been found that the signals that give the cells their positional information as the limb develops are the same in the arm/ wing, as they are in the leg. So why is the wing so different from the leg?The recent experiments have identified genes that confer “legness”, and this is very exciting for all those working in this general area. One of these genes goes by the unhelpful name of Pitx (it was originally discovered in relation to the development of the pituitary gland).

Using a special virus as a carrier, workers at Harvard expressed Pitx in the developing wing. The result was striking – instead of wing digits, structures much more like toes developed. It is an important step in our understanding of how organs develop, though there is still a long way to go. But since as many as 5 per cent of children are born with some sort of abnormality, it could play a significant role.And why is Pitx on in the leg and not the wing? That is another story, for another time.The writer is professor of biology as applied to medicine at University College London. Gordon Cherry has a skill few of us can comprehend, let alone explain. He can, if you ask him, tell you which day of the week it will be on any future date you care to mention – say, 18 June, 2099. He is one of that select group of people who can calculate, within seconds, the weekday of more or less any date, past or future.