What does that mean?

Rhoda.

I haven't seen him for nearly two years.—I can't remember much about the person I was, two years ago.

Michaelis.

Yes! Yes! I understand.

He turns away, lifting his hands, speaking half to himself.

That these lives of ours should be poured like a jelly, from one mould into another, until God Himself cannot remember what they were two years ago, or two hours ago!

Rhoda.

Why do you say that?

He does not answer, but walks nervously about. Rhoda, watching him, speaks, after a silence.