Letters.

Know what amine?

Your story on trace amines in the brain ("Obscure brain chemicals draw new attention," SN: 7/21/01, p. 37) neglected to mention the most interesting and well-studied of these, the powerful endogenous hallucinogen N,N-dimethyltryptamine (DMT). DMT's role in endogenous psychosis was studied intensively in the 1960s, before research with these drugs became so controversial. We recently subjected DMT to intensive study in a group of normal volunteers. Our inability to invoke tolerance, as well as others' findings that DMT crosses the blood-brain barrier, continues making DMT the most likely candidate for a trace amine of great physiological significance.

Rick J. Strassman
University of New Mexico
School of Medicine
Taos, N.M.

Reinventing the wing?

In your article on powered exoskeleton development ("Dances with robots," SN: 6/30/01, p. 407), you mention the one-person flying machine being developed by Millennium Jet to fly at more than 70 miles per hour, at altitudes of 2,400 meters (7,900 feet), and for a "maximum load of 200 kilograms" (440 pounds). This project is an attempt to recreate a solution provided more elegantly 20 years ago by Williams Research Corp. with their demonstrated flight capability of the Williams Aerial Systems Platform (WASP) II, which was capable of 65-miles-per-hour level flight, altitude of 10,000 feet, and a combined load of pilot, fuel, and payload of 518 pounds. Why are the taxpayers paying good money to reinvent the wheel?

Michael J. Dunn
Auburn, Wash.

The jet-engine-powered WASP could fly only for a few minutes on a tank of fuel, had control problems, and was as noisy as a jet plane, according to Michael Moshier, who heads Millenium Jet in Sunnyvale, Calif. In contrast, the flying platform his company has been developing is expected to cruise stably for hours per tank using relatively quiet fan engines, he says. --P.W.