It's written here.

My sisters gave me this to-day.' She offered the little volume.

He took it as though it were something fragile, and--the sculls fixed under his elbows--turned to the fly-leaf.
'What?
It is _your_ birthday ?' 'Yes.

I am twenty-one.' 'Will you let me shake hands with you ?' His pressure of her fingers was the lightest possible.

'Now that's rather a strange thing--isn't it?
Oh, I remember this book very well, though I haven't seen it or heard of it for twenty years.