THE CINDERELLA OF THE SENSES

Lyall Watson says there's nothing like a good sniff

WE may be naked apes but there is anoth- er, more fundamental way in which we dif- fer from our nearest relatives. We have more skin glands than any ape — or any other animal, for that matter.

Our two square yards of epidermis almost enough to make a bedspread — are perforated by three million sweat glands producing as much as a gallon of fluid every day, Most of this is coolant, evaporating to keep the surface of our bodies from over- heating, but all of it is also scented with per- sonal information. Sweat glands are most numerous, four times more dense, on the palms of our hands and the soles of our feet — right where they would need to be if their secondary function was to act as some sort of territorial marker.

That seems to be precisely what is going on. A recent study, involving subjects with clean hands, has found that fresh palm prints nevertheless leave traces that human volunteers can identify as either male or female. Telling two men or two women apart is harder, but it is possible for almost everyone to discriminate even between identical twins, as long as the two have been on different diets for at least three days. And our fragrance doesn't end there. Apart from sweat producers, we have two addi- tional skin glands, One secretes a thick oil whose original function seems to have been to condition and waterproof our fur. It con- tinues to work that way on the scalp, but most of our sebaceous glands are now dedi- cated to producing social and sexual odours, spreading their moody magic in concentra- tions around our lips, eyelids and nipples.

The third kind of gland is our most emo- tive one. Each is a little coiled tube, large enough to be seen by the naked eye, open- ing on to hair roots, mainly in the groin and under our arms, where they are heaped up two or three to a follicle, coat- ing us with their oils, vaporising easily in the warmth, dissolving and spreading with the aid of sweat which keeps these moist and hairy areas bacterially active.

Secretions from these apocrine glands have no detectable odour, but contain vis- cid oils, coloured anything from milky white to blood red, which decompose into a volatile cocktail of fats and hormones that is carried off on rafts of more than 40 million flakes of skin we shed each day and leave behind us — like a vapour trail of invisible but scented dandruff.

Any dispassionate extraterrestrial biolo- gist would have very little hesitation in describing our species as one with a very active olfactory communication system. We smell! We are not so much naked apes as fragrant apes; scent factories marvellously well equipped for chemical communication. And yet we still persist in belittling our own olfactory abilities, dismissing the human nose as a blunt instrument.

Smell is the Cinderella of the senses, the forgotten faculty. There are no agreed measures of its nature, no societies dedi- cated to its appreciation or devoted to the care of those who suffer from its loss. The blind, the deaf and the mute are all catered for, but those who cannot smell are left hanging. They suffer from an absence without a name. Smell-no-evil is a condition that doesn't deserve a monkey.

But smell is ubiquitous. It is the only sense you can't tum off. You can close your eyes, cover your ears, refrain from touching or tasting, but you smell all the time and with every breath, as often as 20,000 times a day. Smell is the only direct sense, commu- nicating with the brain without any of the filters that shape and predigest information collected by any other sense.

No! No! It's you can never be toon thin or too rich.' It is true that the sense of smell in many other mammals is more acute. Hedgehogs are 10,000 times better at finding food by smell; dogs are a million times more likely to pick up social smells. But the fact is that most olfactory communication is encoded in ways that require recognition in the brain, and the bigger the brain, the more sense it can make of limited information. This raises the surprising possibility that, where smell is concerned, we may be the most evolved of any species.

Trained human noses can identify hun- dreds of thousands of odours, far more than any of us can describe. Experts end up hav- ing to borrow descriptive terms from the vocabularies of other disciplines. But all of us manage anyway to use our noses to dis- tinguish between good and bad food, to detect danger and diagnose disease. (Tuber- culosis carries the sour scent of stale beer, and diabetes has the sharp odour of ace- tone.) Tests have also shown that, without training, any of us can follow the menstrual cycle of strangers and identify close relatives by smell alone. And everyone knows how provocative smell can be in conjuring up old memories in extraordinary detail. So why our ambivalence about smell?

I think I know. We have been missing something. We have become so thoroughly bewitched by the bravura productions of our sense of sight that we tend to overlook smell's subtleties. We think of smell simply as the conscious perception of odours, ignoring the possibility that our noses, like our eyes and ears, are tuned only to a nar- row range of frequencies. And hot on the heels of the discovery that bats and ele- phants operate on ultrasound and infra- sound, neither of which we can hear, comes the news that we have a second system of smell: one designed to monitor chemical signals that have no obvious odour; one whose secret lies in an obscure body part. And one that has been there all the time right under our noses.

It is easy to miss. The external evidence consists simply of a pair of tiny pits, one on each side of the nasal septum, half an inch up each human nostril. This elusive feature is the Organ of Jacobson, named after a sharp-eyed Danish anatomist who discov- ered it almost two centuries ago. There are passing mentions of it in works dedicated to comparative anatomy, but in most text- books it fails to be described at all or tends to be dismissed as something vestigial, a useless structure that makes only a tran- sient appearance in the human embryo, vanishing well before birth.

Studies in the last decade, however, show that it not only exists in every one of us, but still functions. And what it does is to open up an alternative channel, quite separate from the main olfactory system. It is a ner- vous connection that monitors hormones and a host of other odourless and under- cover patterns of chemical information and sends news of these directly to the lim- bic system, an old part of the brain where many of our most basic behaviours and emotional states are still organised.

The kind of signals with which Jacob- son's Organ is concerned are so subtle as to be subliminal or almost non-existent. And these fascinate me because I believe they may lie behind once-unexplained, sci- entifically unmentionable things such as hunches, good and bad `vibes', instant dis- likes and irresistible attractions.

For me, Jacobson's Organ provides the mechanism necessary for coming to terms with some of the mysteries of awareness. Here, finally, is something that could be behind the operation of a true `Sixth Sense'. And, even if it fails to fulfil that heady promise, it at least makes sense of our grow- ing passion for fragrances and perfumes from an industry that is flooding the market- place with thousands of scented offerings now worth well over £3 billion a year.

Jacobson's Organ and the Remarkable Nature of Smell by Lyall Watson is available from The Spectator Bookshop. To order please call 0541 557288 and quote ref. SP151.