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Special announcement: Clin-ton is not a chemist.

A number of people called us and also called the White House to ask if it was true that Bill Clinton won the Nobel Prize for chemistry, as we asserted in a recent column on FDR.This goes to show that we live in a world so preposterous it is impossible to make a comment with enough preposterousness to be distinguishable from the normal background madness. Rest assured that Clinton is a lawyer. To our knowledge, he couldn't tell the Periodic Table from a floor plan of the West Wing.

Then again, if Yasser Arafat can win the Nobel Peace Prize, anything's possible.

Question: Why are there no giant insects?

Answer: Whenever you're feeling kind of mopey, or bored or discontented with your lot in life, just remind yourself: At least you're not being borne aloft by a wasp the size of a helicopter.

We are not the types to say negative things about insects - in fact we consider the word "bug" to be pejorative - but we will confess that we are glad that the hideous little monsters are small enough to squish. Why is there not a single gargantuan species of insect, other than in horror movies?


Bugs, you see, don't transport oxygen to their body parts the way we do. We have a circulatory system in which blood cells take oxygen from the lungs to the cells. Bugs don't have lungs. They don't have blood quite like we do. The way they get oxygen is through vents.

Tiny holes in the surface of the insect allow oxygen to enter the body. These hollow passages branch into ever-finer tubes, carrying oxygen to all the bug parts. This is an excellent system for a small creature, says Chris McGowan, curator of vertebrate paleontology at Royal Ontario Museum and author of "Diatoms to Dinosaurs: The Size and Scale of Living Things."

The problem is that a "tracheal system," as it's called, wouldn't be effective for larger creatures. "As you get bigger, the area to volume ratio gets smaller," says McGowan. In other words, you have relatively more body mass compared to your surface area. You have much more to ventilate but only a little bit more surface for ventilation holes.

"It puts a limit on their body size, so you don't get whacking great big insects," he says.

Why can't some insects just develop lungs and a circulatory system? Because that would require a wholesale change in anatomical strategy. Once we go down a certain evolutionary path, we don't back up completely and take a new route.

There's another reason insects stay small: It works. Have you noticed how many bugs there are? By being small, they're capable of reproducing in enormous numbers without using up too many nutrient resources in the environment. There's a cost to getting big.

Then again, there's a cost to staying small. You can get eaten! This is one major reason small creatures like flies don't live very long, while large or well-protected creatures like elephants or tortoises do. Creatures that run the risk of being eaten tend to live speeded-up lives, with early maturity and passels of offspring.

Another cost of being small - and here we are basically flipping the whole item around so that we can explain why there are no one-inch-tall humans - is your brain wouldn't be large enough and complex enough to get you into a good college. In fact, an insect is largely controlled by decentralized nerve ganglia, mini-brains spread around the body.

McGowan writes that if you surgically remove the pinhead-sized brain from an insect, it will continue to function, only confusedly. It might try to eat, fly and walk all at the same time.

Whereas a human will merely turn on the home shopping channel.

Question: Why is animal feed stored in tall, cylindrical silos?

Answer: Occasionally the Why staff travels into the heartland, and the thing we always notice is that there are still literally dozens of farms out there. Most of these farms tend to use the traditional bullet-shaped silos. Hasn't anyone invented something more practical and uglier, the way they've done with every other artifact of the past?

Here's the secret to silos: They put gravity to work. The grain is funneled into the bottom of the silo. Makes for easy handling of feed, cleaning, etc. If you have a big, spread-out storage structure with a flat floor, asks Dennis Kouma of Behlen Manufacturing Co. in Columbus, Neb., "How do you get it to flow to one center point? The round, tall structures lend themselves to automation in handling and filling and emptying."

Maybe we should get a silo for our mail.

The Mailbag:

"Why have we changed centigrade to Celsius?" asks Clayton S. of Coleman, Mich.

Dear Clayton: One is the name of a scale. The other is a descriptive nickname.

The Celsius scale is named after the Swedish astronomer Anders Celsius, who chose the melting point of ice as 0 degrees and the boiling point of water as 100 degrees. Because of the 100 equal units between freezing and boiling, the scale became known, commonly, as centigrade, because that had a nice descriptive Latinate quality to it (as in centimeter, centipede, one red cent, centavo, etc.).

The centigrade scale was officially named the Celsius scale by some high-falutin' international committee in 1948. You can still say centigrade if you wish, but it does sound kind of retrograde.

Washington Post Writers Group