Letters from the February 16, 2008, issue of Science News

Inert placebo?

Regarding “Getting the Red Out” (SN: 1/19/08, p. 35): While drug companies wish to market their products, my attention is drawn to the fact that 1 in 8 of the control group of psoriasis patients was cured by placebo effect. Who will investigate the process therein? Is there a market for it?

Carson Barnes
Loma Mar, Calif.

A potent placebo effect, even of 12 percent, isn’t unheard of in medical studies. To find out more about the placebo effect and efforts to capitalize on it, see “Medicinal Mimicry: Sometimes, placebos work—but how?” (SN: 2/3/01, p. 74) and “Intrinsic Remedies for Pain: Placebo effect may take various paths in brain” (SN: 1/21/06, p. 37).—Nathan Seppa

Time of death

“Struck from above” (SN: 1/5/08, p. 14) suggested yet a second possibility leading to the decline or extinction of the mammoths in the region of the apparent iron micrometeorite-shower impact, which drove the metallic particles into the sides of the fossil tusks examined. That same shower of high-velocity metallic particles found in the tusks probably perforated the skin and soft tissues of the mammoths, causing extensive hemorrhaging and more or less immediate, widespread death rather than having “rendered much of northern Alaska inhospitable for decades.”

Carl B. Mankinen
Jacksonville, Fla.

This study focuses on the mammoth tusks, but a skull of a Siberian bison shows signs of bone growth after similar particles became embedded in it, suggesting the creature survived the event. Because the outer layers of tusk material are already dead (essentially, a tusk is a big tooth), it’s impossible to tell whether the mammoths survived the event.—Sid Perkins

Survival of the bravest

There is little mystery why some female fishing spiders are so aggressive that they eat their suitors before mating can take place (“Not So Spineless,” SN: 1/5/08, p. 10). It would take a very bold male to court a female knowing he is going to be lunch. To maintain such inherited aggressive behavior in the female, one only has to assume that both sexes inherit the same aggressive trait.

Robert Stenton
Cincinnati, Ohio