I can't remember what my grandmother smelled like. I know she smelled like something - something specific and complex that I knew without thinking, something that was completely her. I remember knowing it. I remember the certainty of it, the way you move toward a smell that means safety. The fact of the smell remains in memory. The smell itself is gone.

I've been told you can't remember smells the way you remember images or sounds. That olfactory memory is immediate or it's nothing - the brain doesn't store the smell itself, only the emotional index. So if I haven't smelled it in eight years since she died, the original is gone. I've been trying to reconstruct it. Old women's powder, maybe. Something floral but not sharp. Wool. I've smelled things in stores and felt almost - almost. But not quite. The memory knows it's not right. It rejects the substitutes the way the body rejects wrong blood.

I have one photograph where you can almost see it - the particular setting of her shoulders, the way she inclined toward whoever she was near. My mother says she smelled like lavender. My aunt says roses. Neither memory matches mine, and mine is already gone anyway.

What I want back isn't the smell exactly. It's the certainty. The knowing without thinking. The animal recognition of someone who was home.

What do you hold in memory that can't be verified anymore? Are you certain it was true, or is the certainty itself the last remaining piece?