Jacobson's Organ and the remarkable nature of smell
by Val Stevenson
[ bookreviews ]
Linnaeus' taxonomy of smells - he categorised them into fragrant, goaty, ambrosial, foul, nauseating, aromatic and garlicky - represented a stab at overcoming the lack of a specialised vocabulary of smelling. A smell may be capable of transporting us back to our childhood, but describing it will defeat us; we tend to fall back on the language of taste. Helen Keller rightly described it as "the fallen angel of the senses." Lyall Watson has written a book about odours, in particular the role of Jacobson's Organ in their perception. Smell is, he says, "an emotional sense, rather than an intellectual one." It is more open to synaesthesia with the other senses, more liable to be perceived unconsciously.
Recent research published in the British Journal of Psychology about the ability of smells to increase subjects' recall of events seems to confirm Watson's thesis. In tests following a visit to the Jorvik Museum in York, subjects who had been exposed to the smell of the Viking lavatories, burnt wood and apples while passing associated exhibits, remembered their visit up to 20 per cent more clearly than the control group. Smells have also been used to reorient people with memory problems, and the loss of the sense of smell can be deeply upsetting - there is a high suicide rate among anosmics.
Jacobson's Organ is a pair of tiny pits up the nostril, which enable us to tune into the world of subliminal messages described by science writer Karen Wright as "bad vibes, warm fuzzies, instant dislikes and irresistible attractions". These pits, discovered by 18th century Danish anatomist Ludwig Jacobson, respond to odourless substances which convey information about gender, reproduction, and dominance status to the reptilian brain, our "cognitive fossil".
The nose and Jacobson's Organ provide separate but parallel smell detection systems with different receptors. The nose may be aware of the dreaded BO, but the Jacobson's Organ will home in on the pheromones' come-hither call. Our obsession with scrubbing, deodorising and depilating ourselves is fairly recent: Joris-Karl Huysmans described a heroine's armpit which "easily uncaged the animal in men"; and Napoleon instructed Josephine (who, at other times, wore so much musk that her servants had been known to faint) not to wash. Our full-scale retreat from our own smells has elements of farce, though.
According to Plutarch, Cleopatra sailed down the Nile in such an eye-watering miasma of perfume that "even the winds were love-sick"; Mark Anthony was, literally, led by the nose. The top notes of perfumes contain flower oils designed to attract pollinators, and the middle and bottom notes resemble mammalian sex steroids and pheromones. We consciously remove our animal smells, and then drench ourselves with bottled sex. (The French have a magnificent term for down-and-dirty perfume: "parfum de fourrure", fur perfume. The English, faced with voluptuousness, hiss through pursed lips: "all fur coat and no knickers.") The grail of the perfume industry is a dab-on Viagra, a perfect pheromone-delivery system. (Is Pfizer aware that 'vyagra', Sanskrit for male tiger, an animal known for aromatic urine spraying, shares the same root as the verb 'to smell'?) The human male tends not to piss on his Valentine before copulation, but that romantic gift of perfume containing androgenic pheromones might have much the same effect.
In 1991, a number of scientists designed an 'electrovomeronasometer' to measure the effect of non-volatile, non-odorous compounds, and noticed changes in heart rate, respiration, pupil size and the temperature of the smeller's nose. They used it to design what might be described, if the Food and Drug Administration would not object, as an aphrodisiac. We are notable among carnivores for having a weak sense of smell, but even we can tell a lot about a person from their odour. We are pathetic compared to bloodhounds, but breast-fed babies can distinguish their mothers' clothes; and mothers the smell of their babies. We talk about the smell of fear, feel instinctive uneasiness with total strangers, even notice disease. Typhoid smells of freshly baked bread, TB of stale beer. Some diabetic patients' breath smells of acetone, and many psychiatrists recognise the smell of a schizophrenic in crisis. People suffering from cystic fibrosis have the ability to detect some smells at levels massively below the usual threshold. Watson suggests that the smell hallucinations from which some (but definitely not all) schizophrenics suffer may, in fact, reflect their reality, and describes the case of one patient who could smell a cousin, of whom he was fond, when she was out of sight and several blocks away.
At the end of the book, Watson indulges in a spot of speculation about the nature of ghosts. He theorises that a left-over cell - skin or whatever - can leave an olfactory message, apparently from the other side, with a hazy outline, a sketchy biography and often a distinctive smell. This is a thoroughly entertaining book, but I just didn't quite buy the dandruff theory of revenants.
