A Natural History of the Senses (21 page)

Even though grass soup was the main food in the Russian gulags, according to Solzhenitsyn’s
One Day in the Life of Ivan Denisovich
, humans don’t prefer wood, or leaves, or grass—the cellulose is impossible to digest. We also can’t manage well eating excrement, although some animals adore it, or chalk or petroleum. On the other hand, cultural taboos make us spurn many foods that are wholesome and nourishing. Jews don’t eat pork, Hindus don’t eat beef, and Americans in general won’t eat dog, rat, horse, grasshopper, grubs, or many other palatable foods prized by peoples elsewhere in the world. Anthropologist Claude Lévi-Strauss found that primitive tribes designated foods “good to think” or “bad to think.” Necessity, the mother of invention, fathers many codes of conduct. Consider the “sacred cow,” an idea so shocking it has passed into our vocabulary as a thing, event, or person considered sacrosanct. Though India has a population of around 700 million and a constant need for protein, over two hundred million cattle are allowed to roam the streets as deities while many people go hungry. The cow plays a central role in Hinduism. As Marvin Harris explains in
The Sacred Cow and the Abominable Pig:

Not only is the cow sacred in India, even the dust in its hoofprints is sacred. And, according to Hindu theology, 330 million gods live inside each cow. There are many reasons why this national tantalism has come about; one factor may be that an overcrowded land such as India can’t support the raising of livestock for food, a system that is extremely inefficient. When people eat animals that have been fed grains, “nine out of ten calories and four out of five grams of protein are lost for human consumption.” The animal uses up most of the nutrients. So vegetarianism may have evolved as a remedy, and been ritualized through religion. “I feel confident that the rise of Buddhism was related to mass suffering and environmental depletions,” Harris writes, “because several similar nonkilling religions … arose in India at the same time.” Including Jainism, whose priests not only tend stray cats and dogs, but keep a separate room in their shelters just for insects. When they walk down the street, an assistant walks ahead of them to brush away any insects lest they get stepped on, and they wear gauze masks so they don’t accidentally inhale a wayward midge or other insect.

One taboo stands out as the most fantastic and forbidden. “What’s eating you?” a man may ask an annoyed friend. Even though his friend just got fired by a tyrannical boss with a mind as small as a noose, he would never think to say “
Who’s
eating you?” The idea of cannibalism is so far from our ordinary lives that we can safely use the euphemism
eat
in a sexual context, say, and no one will think we mean literally consume. But omnivores can eat anything,
even each other,
*
and human flesh is one of the finest sources of protein. Primitive peoples all over the world have indulged in cannibalism, always ritualistically, but sometimes as a key source of protein missing from their diets. For many it’s a question of headhunting, displaying the enemy’s head with much magic and flourish; and then, so as not to be wasteful, eating the body. In Britain’s Iron Age, the Celts consumed large quantities of human flesh. Some American Indian tribes tortured and ate their captives, and the details (reported by Christian missionaries who observed the rites) are hair-raising. During one four-night celebration in 1487, the Aztecs were reported to have sacrificed about eighty thousand prisoners, whose flesh was shared with the gods, but mainly eaten by a huge meat-hungry population. In
The Power of Myth
, the late Joseph Campbell, a wise observer of the beliefs and customs of many cultures, tells of a New Guinea cannibalism ritual that “enacts the planting-society myth of death, resurrection and
cannibalistic
consumption.” The tribe enters a sacred field, where they chant and beat drums for four or five days, and break all the rules by engaging in a sexual orgy. In this rite of manhood, young boys are introduced to sex for the first time:

When the explorer Dr. Livingstone died in Africa, his organs were apparently eaten by two of his native followers as a way to absorb his strength and courage. Taking communion in the Catholic Church enacts a symbolic eating of the body and blood of Christ. Some forms of cannibalism were more bloodthirsty than others. According to Philippa Pullar, Druid priests “attempted divination by stabbing a man above his midriff, foretelling the future by the convulsions of his limbs and the pouring of his blood.… Then … they devoured him.” Cannibalism doesn’t horrify us because we find human life sacred, but because our social taboos happen to forbid it, or, as Harris says: “the real conundrum is why we who live in a society which is constantly perfecting the art of mass-producing human bodies on the battlefield find humans good to kill but bad to eat.”
*

Seen by scanning electron microscope, our taste buds look as huge as volcanoes on Mars, while those of a shark are beautiful mounds of pastel-colored tissue paper—until we remember what they’re used for. In reality, taste buds are exceedingly small. Adults have about 10,000, grouped by theme (salt, sour, sweet, bitter), at various sites in the mouth. Inside each one, about fifty taste cells busily relay information to a neuron, which will alert the brain. Not much tasting happens in the center of the tongue, but there are also incidental taste buds on the palate, pharynx, and tonsils, which cling like bats to the damp, slimy limestone walls of a cave. Rabbits have 17,000 taste buds, parrots only about 400, cows 25,000. What are they tasting? Maybe a cow needs that many to enjoy a relentless diet of grass.

At the tip of the tongue, we taste sweet things; bitter things at
the back; sour things at the sides; and salty things spread over the surface, but mainly up front. The tongue is like a kingdom divided into principalities according to sensory talent. It would be as if all those who could see lived to the east, those who could hear lived to the west, those who could taste lived to the south, and those who could touch lived to the north. A flavor traveling through this kingdom is not recognized in the same way in any two places. If we lick an ice cream cone, a lollipop, or a cake-batter-covered finger, we touch the food with the tip of the tongue, where the taste buds for sweetness are, and it gives us an extra jolt of pleasure. A cube of sugar under the tongue won’t taste as sweet as one placed
on
the tongue. Our threshold for bitter is the lowest. Because the taste buds for bitter lie at the back of the tongue; as a final defense against danger they can make us gag to keep a substance from sliding down the throat. Some people do, in fact, gag when they take quinine, or drink coffee for the first time, or try olives. Our taste buds can detect sweetness in something even if only one part in two hundred is sweet. Butterflies and blowflies, which have most of their taste organs on their front feet, need only step in a sweet solution to taste it. Dogs, horses, and many other animals have a sweet tooth, as we do. We can detect saltiness in one part in 400, sourness in one part in 130,000, but bitterness in as little as one part in 2,000,000. Nor is it necessary for us to recognize poisonous things as tasting different from one another; they just taste bitter. Distinguishing between bitter and sweet substances is so essential to our lives that it has burst through our language. Children, joy, a trusted friend, a lover all are referred to as “sweet.” Regret, an enemy, pain, disappointment, a nasty argument all are referred to as “bitter.” The “bitter pill” we metaphorically dread is likely to be poison.

Taste buds got their name from the nineteenth-century German scientists Georg Meissner and Rudolf Wagner, who discovered mounds made up of taste cells that overlap like petals. Taste buds wear out every week to ten days, and we replace them, although not as frequently over the age of forty-five—our palates really do become
jaded
*
as we get older. It takes a more intense taste to produce the same level of sensation, and children have the keenest sense of taste. A baby’s mouth has many more taste buds than an adult’s, with some even dotting the cheeks. Children adore sweets partly because the tips of their tongues, more sensitive to sugar, haven’t yet been blunted by years of gourmandizing or trying to eat hot soup before it cools. A person born without a tongue, or who has had his tongue cut out, still can taste. Brillat-Savarin tells of a Frenchman in Algeria who was punished for an attempted prison escape by having “the forepart of his tongue … cut off clear to the ligament.” Swallowing was difficult and tiring for him, although he could still taste fairly well, “but very sour or bitter things caused him unbearable pain.”

Just as we can smell something only when it begins to evaporate, we can taste something only when it begins to dissolve, and we cannot do that without saliva. Every taste we can imagine—from mangoes to hundred-year-old eggs—comes from a combination of the four primary tastes plus one or two others. And yet we can distinguish between tastes with finesse, as wine-, tea-, cheese- and other professional tasters do. The Greeks and Romans, who were sophisticated about fish, could tell just by tasting one what waters it came from. As precise as our sense of taste is, illusions can still surprise us. For example, MSG doesn’t taste saltier than table salt, but it really contains much more sodium. One of its ingredients, glutamate, blocks our ability to taste it as salty. A neurologist at the Albert Einstein College of Medicine once tested the amount of MSG in a bowl of wonton soup in a Chinese restaurant in Manhattan, and he found 7.5 grams of MSG, as much sodium as one should limit oneself to in an entire day.

After brushing our teeth in the morning, orange juice tastes bitter. Why? Because our taste buds have membranes that contain fatlike phospholipids, and toothpastes contains a detergent that breaks down fat and grease. So the toothpaste first assaults the membranes with its detergent, leaving them raw; then chemicals in the toothpaste, such as formaldehyde, chalk, and saccharin, cause a sour taste
when they mix with the citric and ascorbic acids of orange juice. Chewing the leaves of the asclepiad (a relative of the milkweed) makes one’s ability to taste sweetness vanish. Sugar would taste bland and gritty. When Africans chew a berry they call “miraculous fruit,” it becomes impossible to taste anything sour: lemons taste sweet, sour wine tastes sweet, rhubarb tastes sweet. Anything off-puttingly sour suddenly becomes delicious. A weak enough solution of salt tastes sweet to us, and some people salt melons to enhance the sweet flavor. Lead and beryllium salts can taste treacherously sweet, even though they’re poisonous and we ought to be tasting them as bitter.

No two of us taste the same plum. Heredity allows some people to eat asparagus and pee fragrantly afterward (as Proust describes in
Remembrance of Things Past
), or eat artichokes and then taste any drink, even water, as sweet. Some people are more sensitive to bitter tastes than others and find saccharin appalling, while others guzzle diet sodas. Salt cravers have saltier saliva. Their mouths are accustomed to a higher sodium level, and foods must be saltier before they register as salty. Of course, everyone’s saliva is different and distinctive, flavored by diet, whether or not they smoke, heredity, perhaps even mood.

How strange that we acquire tastes as we grow. Babies don’t like olives, mustard, hot pepper, beer, fruits that make one pucker, or coffee. After all, coffee is bitter, a flavor from the forbidden and dangerous realm. To eat a pickle, one risks one’s common sense, overrides the body’s warning with sheer reason.
Calm down, it’s not dangerous
, the brain says, it’s novel and interesting, a change, an exhilaration.

Smell contributes grandly to taste. Without smell, wine would still dizzy and lull us, but much of its captivation would be gone. We often smell something before we taste it, and that’s enough to make us salivate. Smell and taste share a common airshaft, like residents in a high rise who know which is curry, lasagna, or Cajun night for their neighbors. When something lingers in the mouth, we can smell it, and when we inhale a bitter substance—a nasal decongestant, for example—we often taste it as a brassiness at the back of the throat.
Smell hits us faster: It takes 25,000 times more molecules of cherry pie to taste it than to smell it. A head cold, by inhibiting smell, smothers taste.

We normally chew about a hundred times a minute. But, if we let something linger in our mouth, feel its texture, smell its bouquet, roll it around on the tongue, then chew it slowly so that we can hear its echoes, what we’re really doing is savoring it, using several senses in a gustatory free-for-all. A food’s flavor includes its texture, smell, temperature, color, and painfulness (as in spices), among many other features. Creatures of sound, we like some foods to titillate our hearing more than others. There’s a gratifying crunch to a fresh carrot stick, a seductive sizzle to a broiling steak, a rumbling frenzy to soup coming to a boil, an arousing bunching and snapping to a bowl of breakfast cereal. “Food engineers,” wizards of subtle persuasion, create products to assault as many of our senses as possible. Committees put a lot of thought into the design of fast foods. As David Bodanis points out with such good humor in
The Secret House
, potato chips are: