I should like to experiment a bit about that cat if you don't mind, Miss Trelawny." She hesitated before replying: "Of course, do anything you may think necessary or wise; but I hope it will not be anything to hurt or worry my poor Silvio." The Doctor smiled as he answered: "Oh, Silvio would be all right: it is the other one that my sympathies would be reserved for." "How do you mean ?" "Master Silvio will do the attacking; the other one will do the suffering." "Suffering ?" There was a note of pain in her voice.

The Doctor smiled more broadly: "Oh, please make your mind easy as to that.

The other won't suffer as we understand it; except perhaps in his structure and outfit." "What on earth do you mean ?" "Simply this, my dear young lady, that the antagonist will be a mummy cat like this one.

There are, I take it, plenty of them to be had in Museum Street.

I shall get one and place it here instead of that one--you won't think that a temporary exchange will violate your Father's instructions, I hope.