Memory seems to have rules of its own. You can pass by a place a dozen times and nothing happens, and then, without warning, the past is right there in front of you, smells and sounds and leaf shadow and the feel of the grass under your bare feet, and that particular place is transfigured forever.

The other Sunday I strolled through the sprawling gardens of Dumbarton Oaks, and for the first time I noticed the long, grassy avenue, overarched by oaks, which slopes down the eastern side.

There is a fish pond at the upper end, and that was what I had come to see: usually I visit Dumbarton in the winter, when everthing is stripped and stark and the oval pond is romantically black and bottomless. I can't understand why I had never been struck by the green alley before. Because as I walked down it I was overwhelmed with memory . . .

It was a cousin's farm, just up the road from the Sadquada golf club outside Utica. They had a sort of swimming hole, lined with stones, and we'd go there on those broiling August afternoons that somehow are always a surprise in upstate New York. Most often, we'd been courting sunstroke by playing furious, vindictive tennis at the club; a few went in for golf, then considered an adults' (i.e. old folks') game. There was no pool at the Sadaquada. A pool was held to be slightly declasse, I suspect, because the upstart Yahnundasis club had one. (The two clubs dominated neighboring hills, and on the Fourth of July we would watch each other's fireworks. The Yahnundasis always had more. We found it a trifle vulgar.)

You changed in a bedroom at the farm, put your sneakers -- unpleasantly cold with sweat -- back on your bare feet untied, threw your towel around your neck (my mother had a fox fur whose glass-eyed head was made to bite its tail, the poor, insulted creature, and I always thought of it then), and burst out by the cringing screen door -- can you hear the sound? Do you have to be 53 years old to remember that? -- and walked down to the pool.

The grass was ankle deep by August. After a thunderstorm it would lie flat. At one time an actual road had led down to the place, and there were still two parallel tracks of small stones that seemed designed to fit excruciatingly into your arches. That was why you wore your sneakers.

The trees on either side were poplars, their leaves twirling lazily in the summer breeze. We hardly noticed, because our steaming skin yearned for that pool, and when we reached it we flung off the towels, shucked the flapping sneakers and dove in.

Oh, the water was cold. And then warm. And then cold. We would tread water in the warm spots, but they never mixed with the icy springs that created the pool. It was vaguely rectangular, with the top layer of stones more or less paved, a handmade pool, a hole in the ground, with long grass that drooped over the edges, and a bottom slimy with mud if you dived down that far. dAnd frogs. Even now, so many years later. I can see that pool as sharply as if I were there this minute.

But it is gone. The farmhouse is gone. The poplars are gone. The two-lane blacktop I used to bicycle on to reach the club, a hot six-mile ride from Clinton, my tennis racket stufed down the back of my shirt, my bathing suit and towl in the basket: the road is a freeway or something. And the cousins who lived there -- they are scattered, I don't know where, I don't keep up with them as I should. The place is a subdivision now, and I couldn't possibly find the exact spot where that pond used to be.

Besides, the Sadaquada has a pool of its own, gunite and chrome, very nice, just across from the putting green, full of whole new generation of cousins all summer.

But no frogs.

They say that one of the great things about getting older is that you have this three-dimensional sight, that something you see today reminds you of something you saw a long time ago, that the past enriches the present. Well, it is great, I guess. My present is enriched, all right. I'm not so sure it is all that wonderful to be reminded, but still . . .