People do love keeping photographs - of their family, friends and of themselves. There are always some small photos in the wallet, wedding portraits on the fireplace shelf and a lot of pictures just everywhere and from everywhere. Why do people keep photographs? An interesting discussion presents an extract from Agatha Christie's "Mrs. McGinty's Death".

Why do people keep photographs?

Why? Goodness knows! Why do people keep things - junk - trash, bits and pieces. They do - that's all there is to it!

Up to a point I agree with you. Some people keep things. Some people throw everything away as soon as they have done with it. That, yes, it is a matter of temperament. But I speak now especially of photographs. Why do people keep, in particular, photographs?

As I say, because they just don't throw things away. Or else because it reminds them - Poirot pounced on the words.

Exactly. It reminds them. Now again we ask - why? Why does a woman keep a photograph of herself when young? And I say that the first reason is, essentially, vanity. She has been a pretty girl and she keeps a photograph of herself to remind her of what a pretty girl she was. It encourages her when her mirror tells her unpalatable things. She says, perhaps, to a friend: 'That was me when I was eighteen...' and she sighs... You agree?

Yes - yes, I should say that's true enough.

Then that is reason. No. 1. Vanity. No reason. No. 2. Sentiment.

That's the same thing?

No, no, not quite. Because this leads you to preserve, not only your own photograph but that of someone else... A picture of your married daughter - when she was a child sitting on hearthrug with tulle round her... Very embarrassing to the subject sometimes, but mothers like to do this. And sons and daughters often keep pictures of their mothers, especially, say, if their mother died young. 'This was my mother as a girl.'

I'm beginning to see what you're driving at, Poirot.

And there is, possibly, a third category. Not vanity, not sentiment, not love - perhaps hate - what do you say?

Hate?

Yes. To keep a desire for revenge alive. Someone who has injured you - you might keep a photograph to remind you, might you not?