THAT’S THE WAY THE COOKIE CRUMBLES (20 page)

The Burlington Arcade in the heart of London is a shopper’s dream. In this fascinating place, you’ll see one-of-a-kind antiques, piles of cashmere sweaters, and unique jewels glistening in showcases. Mere mortals can’t actually afford to buy much there, but I was determined to come away with something. My chance came in a soap shop. That’s right, a soap shop — a shop that sells nothing but soap. And this is no ordinary soap; it’s special, handmade, designer soap. I thought that some of this wonderful soap would make a good souvenir, since soap making is one of the oldest chemical processes known to humankind.

According to Pliny, the Roman historian, the Phoenicians fabricated the first soap in about 600 B.C. from boiled goat fat and caustic wood ashes. The ashes served as a source of sodium and potassium hydroxides (lye), which reacted with the fat to produce soap. A more captivating story links the discovery of soap with Sapo Hill on the outskirts of Rome, a site where ancient Romans sacrificed animals to heathen gods. To do their washing, local women used clay they found at the foot of the hill, on the banks of the Tiber, because of its remarkable cleaning properties. Fat from the sacrificial animals had apparently reacted with hot wood ash to form soap; the substance was washed down to the riverbank and absorbed by the clay. An enterprising American company now manufactures soap “the old-fashioned way” under the name Sappo Hill. The only sacrifice involved here is made by the consumers who open their wallets wide to buy the stuff.

Fats are composed of a backbone of glycerol linked to three fatty acids, and we refer to them, accordingly, as triglycerides. Lye breaks the linkages, liberating glycerol and forming species known as the sodium or potassium salts of the fatty acids. These are soaps. They are characterized by a long tail of twelve to eighteen carbon atoms and a head that features two oxygens that have grabbed the sodium or potassium ions furnished by the lye.

Soap has a double-barreled cleaning action. The tail is soluble in oil, and the head is soluble in water. Most dirt is of an oily or greasy nature, and it attracts the tail, leaving the head to be anchored in water. Rinsing then pulls the oily dirt off whatever surface it is attached to.

Soap also changes the wetting ability of water. It may sound bizarre to talk about the wetness of water, but, in a scientific sense, not all water is equally wet. Wetting is a measure of the ability of water to spread. Normally, water on a surface will form beads. This is because water molecules are attracted to each other more strongly than to a surface or to air. But if we dissolve soap in the water, then its molecules will gather at the surface, since water repels the long hydrophobic (water-hating) tail. This reduces the attraction between water molecules at the surface and allows for easier spreading. The water can now wet a surface more thoroughly and clean it more efficiently.

The Romans and the Phoenicians may have had soap, but its use declined with the rise of the Christian Church, which warned its followers of the evils of exposing the flesh, even to bathe. Only as Europe emerged from the Dark Ages did people’s thoughts turn to cleanliness. Still, soap was only for the filthy rich. A friend of Queen Elizabeth boasted that she “hath a bath every three months whether she needed it or no.” Soap was very expensive; this was due partly to the cost of manufacture but mostly to the taxes imposed upon it in 1712, during the reign of Queen Anne. These taxes remained in effect for 150 years, and it was a serious business. No one could manufacture soap without having a taxman on the premises; and every batch had to be completely accounted for. Some candle makers tried to cheat the taxman by making soap on the side, but the government got wind of this and deemed it illegal for candle makers to possess lye.

Today, we can make soap very cheaply, thanks to Frenchman Nicolas Leblanc, who, in 1879, discovered a method of making lye from brine. Yet Leblanc’s breakthrough certainly isn’t reflected in the prices they charge for soap at Immaculate House in the Burlington Arcade. You can invest your annual salary in their lavender, marmalade, or flower garden soap. The little scroll included with the soaps reveals that they are all made from palm, coconut, olive, and sunflower oils, which have been reacted with sodium hydroxide, or lye. Just like any other soap. But, of course, there are the extras: the flower garden has marigolds and roses; the lavender is studded with lavender flowers; and the marmalade — well, that contains little bits of orange peel. Sounds great for washing out a dirty mouth. And how well do these soaps work? As well as any other. Truth be told, there is not much difference between soaps. That’s why marketers have to resort to gimmicks. Some soaps have added fat or lanolin, and they tout their moisturizing effects. Others leave in lots of glycerol, which makes them transparent. “Gentle to the skin!” scream some labels. Indeed, some highly alkaline soaps may strip the skin’s natural oils and cause more irritation than products that have a pH (measure of alkalinity or acidity) close to that of water. By and large, though, soap is soap. Find one you like and use it often. Especially on your hands. Frequent washing undoubtedly reduces the risk of microbial illness. No special ingredients needed.

I hope I’ve managed to clean up some of the confusion surrounding soap. It’s a necessary task. I know, because I once asked some elementary school students if anyone knew what soap was made of. One bright youngster confidently blurted out “Ivory!” But, judging by the soap prices at the Burlington Arcade, I cannot definitively rule this out.

The performing fleas were among the highlights of P.T. Barnum’s traveling circus. The tiny creatures demonstrated their strength by drawing carriages 131,000 times their own weight; they also played music and walked on water. Now, walking on water is not so hard if you’re a flea. And it has nothing to do with fleas being less dense than water. They’re not. It has to do with one particular property of water: surface tension.

Water is made up of molecules in which two hydrogen atoms are attached to an oxygen atom. Everyone knows that. But not everyone knows that there is also an attraction between the hydrogen atoms of one molecule and the oxygen of another. These hydrogen bonds, as they are called, are quite weak, yet they have a significant effect on water. Attraction between adjacent molecules causes the water surface to develop a virtual skin. Just try to push your finger slowly into a glass of water. The surface will actually bend before the finger punctures it. Or try placing a paper clip — clearly heavier than water — on the water surface. If you do this carefully enough, the paper clip will float. And so will a flea.

Surface tension may permit fleas to walk on water, but it creates a real problem for us when it comes to washing. Ideally, for cleaning purposes, we would like water to flow unimpaired into the nooks and crannies of whatever material we are trying to wash. But water has a resistance to flow, a phenomenon that is apparent when we observe a drop on a glass surface. Instead of spreading freely, the water forms a bead. To allow the water to spread, and thus enhance cleaning, we must decrease the attraction between adjacent water molecules. This is where surfactants come in. These consist of molecules that interfere with the attraction between water molecules and actually increase the ability of water to wet a surface.

The earliest example of a surfactant is soap. Soap, as we have seen (page 200), is not only great at reducing surface tension, but it also binds dirt to water. It consists of long molecules, one end of which is soluble in water, the other in oil. So, one end of the molecule anchors itself in the oily dirt, and the other end binds to water, enabling us to rinse the dirt away. The difficulty with soap, though, is that it does not work well in hard water — that is, water that has calcium or magnesium ions dissolved in it. Soap reacts with these ions to form a precipitate, or scum. This problem triggered the search for synthetic surfactants that would have the properties of soap but would not precipitate out in the presence of minerals.

In the 1930s, chemists rose to the challenge and developed the first synthetic detergents, known as branched alkyl benzene sulfonates; they were made from petroleum products. This solved the precipitation problem, but they still had to address another difficulty. Sulfonates did not come out of solution when calcium and magnesium were around, but they still reacted with them. Although the sulfonates stayed in solution, their cleaning ability was compromised. Enter the detergent “builders,” first introduced in 1947 by Proctor and Gamble, in Tide.

Chemists looked for a reagent to add to detergent that would somehow bind the minerals in water, leaving the detergent free to do its job. Phosphates seemed to fit the bill. They were nontoxic and cheap. Manufacturers loaded up their detergent formulations with phosphates; but then, in the 1960s, a new problem cropped up. Rivers and lakes began to develop a strange foam residue, and sometimes suds even emerged from kitchen taps. Alkyl benzene sulfonates, it turned out, were not biodegradable, and they survived their journey through sewage treatment plants. So the chemists went back to the lab to tinker with the structure of the branched alkyl benzene sulfonates and came up with “linear alkyl benzene sulfonates,” which were susceptible to attack by microorganisms. They had solved the foaming river problem.

But the chemists couldn’t relax for long. Blooms of algae replaced the foam in natural waters. Phosphorus is an essential nutrient for plants; it’s one of the three elements, along with nitrogen and potassium, that we incorporate into fertilizer. The algae blooms indicated that water plants were being fertilized. At first, this didn’t seem to pose any difficulty — after all, water plants photosynthesize and produce oxygen, which aquatic life needs. But when the fertilized water plants died, their degradation used up oxygen, and the net result was a reduction of dissolved oxygen and an impairment of aquatic life. One solution was to design sewage treatment plants where phosphates could be removed; the other was for detergent manufacturers to cut back on phosphates and replace them with other builders.

Minerals known as zeolites (hydrated alkali aluminum silicates, for the chemically inclined) are an alternative to phosphates. They are less efficient at binding calcium and magnesium, so we have to use more of them. And their production process is not exactly pollution-free. Recently, researchers have raised another concern about detergents. This one hits below the belt. They have discovered that breakdown products of phenol ether sulfates (a popular detergent) have estrogenic properties. In fact, they are related to nonoxynol-9, a common ingredient in spermicides. Some scientists even link the reduction in average global sperm counts with certain detergents.

We must address this situation, but I don’t think anyone is suggesting that we give up our detergents. They are just too useful. Why, you can even use them to do away with fleas. The little guys are performers at heart. Place a dish of water with a light shining on it in the room where you suspect they are hiding, and add a touch of detergent to the water. The fleas will go for the spotlight and jump towards the “stage.” But because the detergent has reduced the water’s surface tension, there will be no walking on water. Since swimming is not one of the talents that fleas possess, they will sink and drown.

I really don’t understand what Little Miss Muffet’s problem was with spiders. There she was, on her tuffet, happily eating her curds and whey, getting a good dose of calcium, when along came a spider, sat down beside her, and scared her away. It wasn’t even a black widow or a brown recluse, in which case a little trepidation may have been in order. It was a common house spider. How do we know this? Because that’s the species her father kept around the house.

Oh, yes, Little Miss Muffet was a real person. Her real name was Patience, and she was the daughter of Thomas Muffet, a sixteenth-century British physician who kept spiders because he liked them to decorate his rooms with their tapestry. His patients must have thought he was a little bizarre, and certainly Patience had no patience for the arachnids. That’s probably because she knew so little about them.

A bite from a black widow or a brown recluse spider can be life-threatening, but the truth is that you stand a greater chance of being attacked by a shark or struck by lightning than sustaining such a bite. Spiders are actually beneficial. They kill more insects than all birds combined, and far more than insecticides. Each year, spiders eat a quantity of insects that exceeds the weight of the total human population. Now there’s a statistic to chew on!

In the 1970s, Chinese farmers began to harness spider power. They discovered that they could employ the eight-legged predators (don’t call them insects, because that’s not what they are) to patrol cotton fields and protect the plants from insect infestation. They house their wolf spiders, jumping spiders, and crab spiders (which paralyze insects with poison instead of ensnaring them in webs) in “spider motels” (straw bundles) in the fields. The arachnids hibernate happily. They wake up in the spring feeling ravenous and ready to gorge on insects. In some areas, pesticide use has decreased by sixty percent. The Australian funnel-web spider may also reduce our reliance on insecticides. One of the compounds in its venom is deadly to cockroaches, crickets, and fruit flies, but it’s harmless to mammals. We may one day be able to produce it through genetic engineering techniques in quantities large enough to combat insects.

Banana spiders live in tropical climates and release a scent that lures cockroaches to their doom. It’s safer than roach sprays. Or, if you have moths, how about some bola spiders? They dangle a strand of silk with a drop of glue at the end and swing it around to catch their prey. Bolas emit an odor that resembles a female moth’s sex attractant, and it is very enticing to male moths. They come looking for love and end up as spider food.

Perhaps even more interesting is the ogre-faced spider that throws a web over its prey — mainly ants — and lifts them off the ground so they cannot leave a scent as a warning to others.

Then, once the web has done its job, the spider eats it and recycles the protein. How’s that for environmental friendliness? Then there is the clever Central American spider that disguises itself as an ant by holding a pair of its legs over its head to mimic antennae. So disguised, it climbs into an ant nest and has a feast.

And how about the male European crab spider? Now there’s a kinky little fellow! During courtship, he spins a veil-like web and uses it to tie up the female. Good thing he does, because the female has a nasty habit of eating the male after mating. But, if the male spins his web properly, he can come and go by the time the female wriggles free.

Not surprisingly, drugs affect a spider’s skill at spinning its web. That’s why NASA scientists think spiders could replace other animals in chemical-toxicity testing. On amphetamine, the spider spins its web fast, but without much planning, leaving large holes. On chloral hydrate, its efforts are spindly and ineffective. If a spider is high on marijuana, the web starts out normal, then loses its pattern; the spider just gets too relaxed and gives up. On caffeine, it strings a few threads together at random. The more toxic the chemical, the more deformed the web. Perhaps, with the aid of a computer program, researchers can quantify the effects and produce an accurate test for toxicity.

You never know when spiders are going to come in handy. A seventy-year-old lady thought she felt a spider bite her, and then she noted red dots on her skin. She started to feel sick, and she consulted several doctors. None of them could diagnose spider bite, but one did detect breast cancer. That spider may have saved the lady’s life. Spiders may save other lives as well. During a stroke, the brain releases a substance called glutamate, and this is responsible for some of the ensuing damage. Researchers have isolated glutamate antagonists from spider venom, and these may be useful in protecting brain cells from damage after a stroke.

Maybe if I’d had the chance to sit down with Patience Muffet and talk to her about spider science, I could have prevented her panic. For in this instance — and in so many other areas of life — ignorance breeds fear. Next time, instead of attacking spiders with chlorpyrifos, cypermethrin, bifenthrin, neem oil, or even a broom, sit down — on a tuffet, if one is handy — and think about how amazing these little creatures are. Then give a thought to how they suspend their webs across what appear to be unbridgeable distances. Maybe you can find more information about this on the World Wide Web.