The incidents of the dog and of the curtain are far more mysterious.

You are positive the door was securely shut ?" "Quite positive." "Could you, after having drawn the curtain, have allowed your hand to slip slightly back, pulling the curtain with it ?" "I don't think so.

I feel sure not." "You know we all constantly make involuntary motions--motions that our minds are quite unaware of." "I do feel sure, nevertheless.

And the dog?
What do you say to that ?" "I don't know what to say.

But dogs are extraordinarily sensitive.