I have already explained that I cannot explain." "A thousand pardons, Professor.

I don't often forget myself, but I did then.

You took me so utterly by surprise." "I fancy that you will be a good deal more surprised before you have come to the end of this affair," was the smiling but almost exasperating reply; "but, as I implied, I can only give you clues.

I cannot even tell you how I get them, and it is for you to follow them or not as your judgment dictates.

Now, here are one or two to go on with.