The Doctor and Polly in “The Moonbase”

I simply don't understand it.

Polly

Doctor, it wouldn't, I mean it couldn't possibly have anything to do with Lister, could it?

Lister?

Polly

Well, I mean, you did say that you took your degree in Glasgow in 1888. It does seem an awful long time from now, 2070 or whatever it is.

Polly, are you suggesting that I'm not competent to carry out these tests?

Polly

Oh, no. No, no, no, no. I was just wondering if there was anything that Joseph Lister didn't know in 1888 that might possibly help you now.

Shh! Somebody's coming. It's Mister Hobson, out for blood. Ours. Look busy. Quick!