The election tomorrow is supposed to be a cliffhanger and that means up to 10 percent of the country's adults may be sitting up late biting their nails. How do I know that many people bite their nails? Because I read the Federal Register, and must admit to constant amazement at the information that can be picked up from it. For example, do you know how fast your fingernails grow?

The Oct 17 Federal Register (page 69122) has the answer and a lot more in a notice of a proposed rule by the Food and Drug Administration to establish labeling and testing of products sold over-the-counter that are supposed to deter nail-biting and thumb-sucking.

FDA has been looking into this matter for five years, so it's not too surprising that they can pepper the notice with facts like nails "normally grow at the rate of 0.1 millimeter daily" and that for those who bite their nails the rate is doubled. There's more: "Nail-biting occurs in 43 percent of preadolescent children, 25 percent of college students, and 10 percent of adults."

Why do we (and I must confess I'm one of the 10 percent, which is clearly why this entire thing is being written) do it? According to FDA, "sometimes" it's a matter of "discontent, pressure, or maladjustment" and most often occurs "in a stressful situation."

The data on thumb-sucking (which I don't do) is more limited. Several studies report the numbers on thumb-sucking children can vary from 16 percent to 46 percent, FDA, apparently to reassure parents, notes that "current thinking" holds it is a "simple habit" and that "finger-suckers are not emotionally disturbed." The notice also says, however, thumb-sucking usually stops spontanelously at about age four."

Now why is the federal government, through FDA, into all this? The products designed to get children and adults to cut out these habits are liquids containing awful-tasting substances to be dabbed on fingernails or thumbs. FDA got into the act because the government wants to be sure the products are safe, labeled correctly, and do what their ads say.

The bitter taste comes from compounds called denatonium benzoate and sucrose octaacetate, finished off with pharmaceutical-grade shellac so they can be painted onto the nail or thumb. FDA tests apparently have shown that if you chug-a-lug a bottle or so, it might kill you -- at least it puts away rats. Of course, tests using far lesser amounts of the substances, though still far more than is found in the commercial products, caused the rats no harm at all.

But since they are for children, FDA wants the label to specify: "For topical use only." I'm not a child so I had to look up "topical" in the dictionary and only then learned it meant to apply on the skin.

FDA also wants to be sure they work. Although the makers have a bunch of tests showing satisfied customers, and one company claims it has had only 192 returns on 165,000 bottles sold, the proposed FDA rule sets up a complicated two-year series of laboratory investigations. Meanwhile, those of us who are not embarrassed by our habit will go on biting our nails until the results are in.