"Are some gringos visiting us?" I ask Doña Lilia. She smiles broadly but before she can answer around the corner come Eddy and Mae Gober and Beth and C. D. Carter, speaking English with an accent that sets very comfortably with my Kentuckian ears. They're all in their forties and fifties.

"For years C. D. and I operated a small clinic in Progresso, Belize," explains Beth. "We're heading back there now for a brief visit, and as we travel we drop in on places like Yerba Buena, just to see how things are going, and to offer any help we can. C.D. and Eddy are carpenters. I'm an anesthesiologist, and both Mae and I are willing to do anything from wash dishes to help during operations. Just so we're kept busy... "

As they talk, I catch myself staring at them, for they are so different from the Mexicans around whom I've been these last weeks. My new friends seem so large and pale -- somehow succulent, like turgid, glossy-white, white radishes. And though they behave perfectly respectfully and in a properly restrained manner, with my Mexicanized eyes, my friends seem to speak unreasonably loudly, to move about too aggressively, and to have on their faces expressions that are too self-assured. Moreover, this English now filling the Casa Grande sounds explosive and almost too full of fricatives and stops -- not at all like musical, rhythmic Spanish. Apparently I'm getting a hint of how Mexicans see us. What a strange thing is this moving in and out of different cultures...

It's a chilly, drizzly day so we linger around the fireplace. Many words are spoken about diseases and the natural cures available for them. My friends seem especially fond of charcoal.

"For diarrhea, medicine overdoses... anything for which poison must be removed from the body, you can take capsules of activated charcoal -- or grind up some yourself, using what's left in the fireplace -- eat it, and it'll clean you out," assures Eddy. "If you have a skin sore or an insect or snake bite, make a paste out of some charcoal powder, slap it over the wound to make a poultice, and it'll draw that poison right out."

Even as my friends speak, a shooting pain emanates from the blistered foot that has bothered me all during the Nuevo Limar trip. Mostly the blister is on a stiff, nerve-damaged toe that doesn't curl properly inside my shoes. Now the toe is grotesquely swollen, bright red, splotched with dark purple, and discharging copious amounts of fluid. I pull off my shoe and sock, and ask if charcoal can help my toe.

Within five minutes Beth has my foot sitting in a tub of water that's so hot I can hardly stand it. After three minutes of that I change to a one-minute, cold foot-bath; then another three minutes of hot water, and a second one- minute cold bath; then the entire cycle is repeated, the third cold bath being the last.

"The hot water opens up capillaries and pores," explains Beth, a tallish, blond woman with short-cropped hair, erect posture and determined-looking face. "This causes the blood with its white cells, which fight infections, to flood into the infected part. Then the cold water causes the capillaries and pores to close up. As the capillaries shrink, the blood carrying the infection is driven out."

Though they say that ground-up charcoal from the fireplace before us would do fine, now Beth empties two capsules of activated charcoal from the camper's medical chest into a folded patch of gauze. This is wrapped in an absorbent bandage and taped onto my foot.

"Tomorrow morning, repeat the treatment," orders Mae. "Then at night do it again. Do it for three or four days. If it still looks bad then, go up and let Dr. Sánchez see it."

The next morning the toe looks the same, but it feels better. The second morning it looks better, too. The third morning it looks so good that I stop thinking about it. In a week the nail on that toe comes out, root and all, but otherwise it heals nicely.