ROANOKE TIMES
Copyright (c) 1997, Roanoke Times
DATE: Tuesday, January 7, 1997 TAG: 9701070060
SECTION: VIRGINIA PAGE: C-1 EDITION: METRO
COLUMN: What's on your mind?
SOURCE: RAY REED
Q: Recently, you reported that drug-screening tests are not likely to produce a false-positive result now, although that could happen several years ago. Please do some research on the chances today of a drug test's giving a false-negative result. Families need to know if they can depend on these tests.
H., Roanoke
A: The tests today are improved, a government chemist said, but the chance of failure can't be completely avoided.
False-positives have been all but eliminated by a two-step testing procedure. If a screening test indicates the presence of a drug, a confirming test is performed on the same urine sample to give the exact level of the drug present.
Screening tests are effective in detecting the drug being targeted, but a negative finding probably wouldn't be followed up with a confirming test.
Several variables can affect test results, such as poor timing. The test must be administered reasonably quickly, before all traces of the drug can be metabolized, said a chemist at the Division of Workplace Programs at Rockville, Md.
Knocking theories
Q: I hear people say "knock on wood" all the time, as in "My car's running great, knock on wood." Where did that expression come from?
V.H., Elliston
A: This phrase, often called up to cancel imagined bad luck, can be linked to several ethnic groups - which might explain why it's so common.
The Morris Dictionary of Word and Phrase Origins lists several theories on where "knock on wood" began, without choosing a favorite.
1. There may be British origins in the phrase "touch wood," perhaps stemming from a childhood game of tag in which anyone who's able to touch a tree is free from capture.
2. An Irish tradition says knocking on wood lets leprechauns know you're thanking them for a bit of good luck.
3. A biblical theory holds that wood symbolizes the cross of Christ, with the idea being that people who make a boast are forgiven if they turn their thoughts to the cross.
4. A Jewish version in which people who were fleeing during an inquisition used a code for knocking on doors to gain admission. This saved lives and developed into the tradition of knocking on wood for good luck.
Carol's origin
Q: I notice that the carol "Away in a Manger" was attributed to Martin Luther on the editorial page on Christmas. Luther probably would have written it in German, and yet it rhymes in English. How can a carol be translated from German to English and still rhyme?
M.L., Roanoke
A: The carol is attributed to the 16th century theologian by tradition, not by fact.
It first appeared in print in 1885 by the Evangelical Lutheran Church in North America. Composition wasn't credited to anyone.
One theory popular among music historians is that "Away in a Manger" was written in the first half of the 19th century by Pennsylvania Lutherans, who presumably would have composed the lyrics in English.
Got a question about something that might affect other people, too? Something you've come across and wondered about? Call us at 981-3118. Or, e-mail RayR@Roanoke.Infi.Net. Maybe we can find the answer.
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