Letters.

The way of the worm

The observation that Buruli ulcer is associated with stagnant or slow-moving water ("Africa's latest scourge," SN: 7/17/99, p. 40) brought to mind the epidemiology of schistosomiasis. Developmental stages of the digenetic trematode responsible for the disease are harbored in freshwater snails. Cercariae, or larvae, from the snails enter the water and penetrate the skin of the final host. Even the cercariae of schistosomes parasitic to birds and animals will often try to penetrate human skin, causing the conditior. known as swimmers itch. Could this be a route of transmission for M. ulcerans? Bacteria could be carried into the skin on the backs of penetrating cercariae, whether the latter are human-specific or not.

Daryl Vanderburgh

Wayland, Mass

No cheer for tide in story

In your article "Against the tide" (SN: 7/24/99, p. 63), the title itself threw me for a slight loss, but I wrote that off to you being a bit poetic in your definition of tide. But then, when you referred to "the highest tides" and later to "tide-gauge records," my disenchantment knew no bounds. The Mediterranean has no tides. The waters may rise briefly and locally in response to heavy rainfall and runoff, but tide qua tide is scarcely measurable.

Anthony Arnold

Novato, Calif

ISO clarity

In the SCIENCE NEWS dated July 31, I read the article "Attractive tree ISO lemur to start a family" (p. 71). Please define "ISO."

Sam Friedland

Mill Valley, Calif

In personal ads in popular magazines and newspapers, the abbreviation stands for "in search of." You may not have expected an allusion to such listings, although they offer considerable data about mating systems. --S. Milius

Reader minds mind reading

Your July 31 issue contained an article on ESP ("ESP findings send controversial message," SN: 7/31/99, p. 70) and referred to a 1994 SCIENCE NEWS article. It bothers me when a prestigious publication lends credence to ESP, Bermuda Triangle mythology, and other nonsense.

I understand that there are those with serious academic credentials who make money by catering to nonsense, but I would prefer that SCIENCE NEWS not go along with such charlatans.

Gouverneur Cadwallader

Philadelphia, Pa.

Flak? Never

In "Squeezing clouds" (SN: 7/24/99, p. 56), there is a picture of an "armored T-28," which is not mentioned in the text.

I sure would like to know why it is armored. Are they taking ground fire from the ranchers?

Pete Saussy

Columbia, S.C.

The planes are armored against hail, not bullets. It is true, however, that some people have tried to stop weather-modification efforts, occasionally using violent means.

--R. Monastersky