To Sacha Lodge

After breakfast at the hotel, and with the assistance of staff from the hotel, Adventure Life, and Sacha Lodge, we made the quick flight to Coca, where we had lunch in the Lodge office while staff transferred luggage. It's a very short walk from there to the dock on the Napo River where we climbed aboard a 60-foot motorized ''canoe''.

The Napo, we learned, is a major tributary of the Amazon, though from where we were the Amazon was 400 miles downstream. Yet even this far upstream the Napo is a spectacular river. I tried to calculate how many Missouris would fit in its banks (three?...four?). Wide as it is, it can also be very shallow (as we were to learn the next day). It's the color of coffee heavily doctored with cream as it carries a huge volume of sandy silt down from the Andes. Heavily braided with islands and sand bars, which change with every storm, and thick with floating logs and snags, it presents a serious challenge to boatsmen. Nevertheless our pilot guided us unerringly for nearly two hours, back and forth from bank to bank as he kept to the main channel. I don't know what our speed was in knots, but the wave of spray we kicked up went four feet above the gunwales.

At a clearing in the jungle we disembarked and as squirrel monkeys played in the trees above us, we walked about a kilometer on a plank path to the shore of Lago Pilchicocha (Squash Lake). Our guides paddled us across to the lodge dock in an eight-person canoe.

Sacha, we quickly discovered, is an enchanting and hospitable outpost of civilization and a great spot for our introduction to the Amazon jungle. Over hors d'oeuvres and ''jungle juice'' cocktails Marco, our guide, filled us in on how the lodge operates: meal schedule, exploratory activities and recreational opportunities.

After an hour to settle in our party of six set out to begin unlocking the secrets of the jungle, with the help of Marco and Macaco, our indigenous guide. We saw cacao fruit growing above our heads, and an endless train of leaf-cutter ants at our feet. They would have been all but invisible except for the bright green, postage-stamp sized leaf fragments they bore relentlessly homeward.

We learned about adaptive strategies among jungle plants: the battle is won by the tall since only one per cent of the sun's light reaches the jungle floor. Several types of root structure have developed to support the tall trees. Some send down dozens of roots in a teepee shape; others, like the kapok, have great flat flanges like the fins on a rocket ship. These flanges are remarkably resonant. When struck, the noise carries far into the jungle and the indigenous people have taken advantage of that to devise a communication system.

After a sumptuous buffet in the lodge we assembled for an unworldly canoe ride through the jungle night. Our flashlights caught the red eyes of a large caiman across the lake but it slipped below the surface as we approached. Paddling quietly up Anaconda Creek we passed directly under a pair of magnificent snail kites 20 feet above our heads. Around a bend a striated heron perched on a branch six feet over the water.

Back in our little thatched cabin suspended on pilings 10 feet above the swamp, a chorus of frogs sang us to sleep.