A squeeze, a touch and there it is.

A white plastic shrine, four or five inches tall, no more. Two tiny doors that open outwards. Inside, the figure of a slight, wistful-looking woman in blue, hands joined in prayer, standing on a sphere that may be the world.

This long-lost treasure was brought to life by a handful of ancient lavender, wrapped in a square of sheer pink organdie – a scrap left over from making a party dress, perhaps – tied with nylon ribbon. It’s old, very old, yet still it works its magic when I come upon it in a drawer.

It was bought at a sale of work held at the first nun-run school I attended. Hence the  statue of Our Lady of Lourdes.

I was thinking about it over Christmas – a particularly fertile time for scent-awakened memories.

Cold December afternoons. Children running home from school, making slides and throwing snowballs. Counting the days, the hours.

At last the tree goes up, perfuming the air. Fairies dance on the branches – just electric lights to grown-ups, but mythical creatures to little, screwed-up eyes.

It still works, as the years sneak by, the Christmas tree. Its scent, its decorations.

And lifting the lid of a small cardboard box sets free a scent that yanks the modern world right out from under my feet.

In a trice I’m standing in a small back garden – not much more than a yard – with a bright green, cheap plastic torch, what my in-house American calls a flashlight. My first, ever. A silver, sliding switch to keep it on, a plastic push button for flashing. English torch, American flashlight.

I can sometimes re-create that magic-carpet of a scent if I close my eyes and just let it happen. It’s a bit like looking at the Pleiades, though. If you stare straight at the stars you can’t see them – and so it is with this delicate scent.

I have to skim my thoughts right past it to find it.

The scent has a colour – green, but not a bright green. A dark, dusty green. An image of ferns comes to mind, but not because of any picture.

For years the nearest thing the world could produce to match my memory was something called ‘French Fern’. An inexpensive perfume. But not cheap, as in tawdry or cloying.

A scent of fine soaps and delicate talcum powders. Of eau-de-colognes, sprinkled on cotton handkerchiefs.

Or so I imagine.

In our boxes of baubles and tinsel, there was always one that, when opened, set loose a fleeting hint of this scent.

But now it’s gone.

A whole box of boxes is gone, and with it, the memories. That’s to say, the memories are still there, but that’s all they are, not a pinprick for the senses, tearing a shining rent in the dusty fabric of time.

And this Christmas also made me think about how wrong we can be about obvious things. That what’s important to me, for example, may not be important to my nearest living blood relative.

When my father had died and my mother was temporarily – finally, as it turned out – living far from her own home, with my sister, I had the melancholy task of emptying her house. I, with my long-suffering husband.

Among the treasured possessions were the Christmas ornaments.

I wanted to keep them all.

For nearly forty years I’d watched them emerge. Helped distribute little figures and paper ornaments around the house.

A robin on a log in a box of cotton wool – he always sat near the lavatory, by tradition. An imp adorned my bedroom door – this year my study.

I’d watch my father set up the crib and arrange glass birds in the Victorian glass dome. Watch as he decorated the tree then later, did it myself, for my mother.

My favourite tree decorations – a white bear in a red aeroplane. A blue and yellow plastic tricycle. A bell-shaped glass bauble that rings.

There were many more.

A turkey wishbone.

Clowns strung on cotton threads (I didn’t like them) and my parents’ home-made ornaments from the immediate post-war years. A crystal button on wire. Paper cut outs decorated in ink. Wooden cotton reels painted yellow, red and gold.

Small glass ornaments in shapes like pine cones and Father Christmas. Brown cardboard boxes of plain glass balls. I loved them so much that it almost hurt to put them away each year.

There were two boxes of those – two sizes, many colours.

I wanted them all.

I gave the bigger and better (I thought) ones to my sister (there, I’ve lost the virtue by telling), along with the clowns she said she liked, in a box that once held a xylophone.

I gave her the wishbone – well, it came from the first turkey that she and my parents had, years before I was born.

I suspect I gave her things she didn’t want, didn’t find evocative in the way I did. I don’t know, and may well be wrong. But by then she had three grown children, her own traditions, her own decorations. Her own scents and sights and triggers for memories.

And perhaps like everything else, scent’s evocative power eventually fades if it’s never used – or used too much.

I can still remember my box, can catch the scent if I set my mind past it. But perhaps it’s time has come – and gone. Like Christmas.