What the Nose Knows - Avery Gilbert [9]
According to conventional wisdom, all major smell classifications can be traced back to the eighteenth-century Swedish naturalist Carl von Linné (1707–1778), known as Linnaeus. Linnaeus was the Big Daddy of scientific classification. In fact, he was a little obsessed with the topic: he classified plants and animals, rocks and sea creatures, and even his fellow scientists. Far from being a muddy-boot field biologist, Linnaeus was a bookish desk-jockey more concerned with defining the single “type” of a species than with the extent of natural variation. For this reason, some historians view him as a rigid essentialist who held back progress in the life sciences for decades. Still, his decision to assign a two-part Latin name to every species—something he regarded as a minor innovation—was a stroke of genius, and it became the basis of all modern taxonomy.
Linnaeus is widely credited among psychologists with inventing the first scientific classification of smells. Very few of them, however, seem to have read the actual treatise, published in 1752. Its Latin title, Odores medicamentorum, translates as “The smells of medicines,” and this is the first big hint that Linnaeus’s primary interest was not smells, but the medicinal properties of plants. He believed he could predict the therapeutic effect of a plant from its odor. To his way of thinking, nonsmelly plants were medically worthless, while strong-smelling ones had great pharmaceutical potency. Similarly, he believed sweet-smelling plants were wholesome, nauseous ones were poisonous, spicy ones were stimulating, and “noisome” ones were “stupefying.” These effects were due to plant smells acting directly on human nerves. You can be forgiven if the views of Sweden’s greatest scientist sound to you like those of a New Age aromatherapist in contemporary Santa Monica.
In grouping medically useful plants by odor, Linnaeus came up with seven classes that translate as fragrant, spicy, musky, garlicky, goaty, foul, and nauseating. His only concern was using smell to classify natural medicines; he did not intend to create a universal classification of all smells. In fact, he had little interest in smells as smells. (This explains the absence of such obvious odor categories as floral, fruity, woody, and leafy green.) Despite his focus on medical properties and his neglect of sensory qualities, European scientists viewed Linnaeus as the first scientific classifier of smells, and the results were a disaster—it sent smell researchers on a wild-goose chase that lasted for two centuries.
The next scientific smell classifier emerged toward the end of the nineteenth century. The Dutch physiologist Hendrik Zwaardemaker (1857–1930) was, by his own account, not particularly interested in smells. His lack of feeling for the topic shows in his work, where his main contribution was to add two new classes (“ethereal” and “empyreumatic”) to those of Linnaeus and to create subdivisions within each class. The new version was complicated and made little sense as a comprehensive classification. (He was, after all, cramming every smell in the world into categories meant to organize only smelly medicinal plants.) Zwaardemaker labored to explain his system, but his tedious cross-referencing of previous classifications has all the prose sparkle of the IRS tax code. Like the system it expanded on, Zwaardemaker’s classification was based entirely on one man’s opinion, rather than on experimental data.
The German physiologist Hans Henning (1885–1946) relentlessly attacked the inconsistencies and absurdities in Zwaardemaker’s classification. He took aim at Zwaardemaker’s preference for lifting odor descriptions from novels and literary works rather than from the direct experience of his own nose. Henning insisted that sensory experience was superior to empty intellectualizing; his motto was “just smell it.” His own classification, proposed in 1916, had two very important selling points: it was based on empirical