That's why I have to keep it on a lead. It would be off to the Hall in a jiffy if I gave it its head.”

“We are getting some cards in our hand, Watson,” said Holmes when the landlord had left us. “It's not an easy one to play, but we may see our way in a day or two. By the way, Sir Robert is still in London, I hear. We might, perhaps, enter the sacred domain to-night without fear of bodily assault. There are one or two points on which I should like reassurance.”

“Have you any theory, Holmes?”

“Only this, Watson, that something happened a week or so ago which has cut deep into the life of the Shoscombe household. What is that something? We can only guess at it from its effects. They seem to be of a curiously mixed character. But that should surely help us. It is only the colourless, uneventful case which is hopeless.

“Let us consider our data. The brother no longer visits the beloved invalid sister. He gives away her favourite dog. Her dog, Watson! Does that suggest nothing to you?”

“Nothing but the brother's spite.”

“Well, it might be so. Or—well, there is an alternative. Now to continue our review of the situation from the time that the quarrel, if there is a quarrel, began. The lady keeps her room, alters her habits, is not seen save when she drives out with her maid, refuses to stop at the stables to greet her favourite horse, and apparently takes to drink. That covers the case, does it not?”

“Save for the business in the crypt.”

“That is another line of thought. There are two, and I beg you will not tangle them. Line A, which concerns Lady Beatrice, has a vaguely sinister flavour, has it not?”

“I can make nothing of it.”

“Well, now, let us take up line B, which concerns Sir Robert. He is mad keen upon winning the Derby. He is in the hands of the Jews, and may at any moment be sold up and his racing stables seized by his creditors. He is a daring and desperate man. He derives his income from his sister. His sister's maid is his willing tool. So far we seem to be on fairly safe ground, do we not?”

“But the crypt?”

“Ah, yes, the crypt! Let us suppose, Watson—it is merely a scandalous supposition, a hypothesis put forward for argument's sake—that Sir Robert has done away with his sister.”

“My dear Holmes, it is out of the question.”

“Very possibly, Watson. Sir Robert is a man of an honourable stock. But you do occasionally find a carrion crow among the eagles. Let us for a moment argue upon this supposition. He could not fly the country until he had realized his fortune, and that fortune could only be realized by bringing off this coup with Shoscombe Prince. Therefore, he has still to stand his ground.