Now, a year later, I suddenly stopped twenty yards away, for at the end of the silvery cadence of a woodhewer, I heard the low, measured, toneless rhythm which instantly revived to mind every detail of the clearing. I was headed toward a distant palm frond beneath whose tip was a nest of Rufous Hermits, for I wished to see the two atoms of hummingbirds at the moment when they rolled from their _petit pois_ egg-shells. I gave this up for the day and turned up the hill, where fifty feet away was the stump and bush near which I had sat and watched. Three times I went past the place before I could be certain, and even at the last I identified it only by the relative position of the giant tauroneero tree, in which I had shot many cotingas. The stump was there, a bit lower and more worn at the crevices, leaking sawdust like an overloved doll--but the low shrub had become a tall sapling, the weeds--vervain, boneset, velvet-leaf--all had been topped and killed off by dense-foliaged bushes and shrubs, which a year before had not raised a leaf above the meadow level. The old vistas were gone, the landscape had closed in, the wilderness was shutting down. Nature herself was "letting in the jungle." I felt like Rip Van Winkle, or even more alien, as if the passing of time had been accelerated and my longed-for leap had been accomplished, beyond the usual ken of mankind's earthly lease of senses. All these astounding changes had come to pass through the heat and moisture of a tropical year, and under deliberate scientific calculation there was nothing unusual in the alteration. I remembered the remarkable growth of one of the laboratory bamboo shoots during the rainy season--twelve and a half feet in sixteen days, but that was a single stem like a blade of grass, whereas here the whole landscape was altered--new birds, new insects, branches, foliage, flowers, where twelve short months past, was open sky above low weeds. In the hollow root on the beach, my band of crane-flies had danced for a thousand hours, but here was a sound which had apparently never ceased for more than a year--perhaps five thousand hours of daylight. It was a low, penetrating, abruptly reiterated beat, occurring about once every second and a half, and distinctly audible a hundred feet away. The "low bush" from which it proceeded last year, was now a respectable sapling, and the source far out of reach overhead. I discovered a roundish mass among the leaves, and the first stroke of the ax sent the rhythm up to once a second, but did not alter the timbre. A few blows and the small trunk gave way and I fled for my life. But there was no angry buzzing and I came close. After a cessation of ten or fifteen seconds the sound began again, weaker but steady. The foliage was alive with small Azteca ants, but these were tenants of several small nests near by, and at the catastrophe overran everything.