“It was on a Mediterranean yachting voyage. The company, though select, paid their own passages. No doubt the promoters hardly realized the Baron’s true character until it was too late. The villain attached himself to the lady, and with such effect that he has completely and absolutely won her heart. To say that she loves him hardly expresses it. She dotes upon him; she is obsessed by him. Outside of him there is nothing on earth. She will not hear one word against him. Everything has been done to cure her of her madness, but in vain. To sum up, she proposes to marry him next month. As she is of age and has a will of iron, it is hard to know how to prevent her.”

“Does she know about the Austrian episode?”

“The cunning devil has told her every unsavoury public scandal of his past life, but always in such a way as to make himself out to be an innocent martyr. She absolutely accepts his version and will listen to no other.”

“Dear me! But surely you have inadvertently let out the name of your client? It is no doubt General de Merville.”

Our visitor fidgeted in his chair.

“I could deceive you by saying so, Mr. Holmes, but it would not be true. De Merville is a broken man. The strong soldier has been utterly demoralized by this incident. He has lost the nerve which never failed him on the battlefield and has become a weak, doddering old man, utterly incapable of contending with a brilliant, forceful rascal like this Austrian. My client, however, is an old friend, one who has known the General intimately for many years and taken a paternal interest in this young girl since she wore short frocks. He cannot see this tragedy consummated without some attempt to stop it. There is nothing in which Scotland Yard can act. It was his own suggestion that you should be called in, but it was, as I have said, on the express stipulation that he should not be personally involved in the matter. I have no doubt, Mr. Holmes, with your great powers you could easily trace my client back through me, but I must ask you, as a point of honour, to refrain from doing so, and not to break in upon his incognito.”

Holmes gave a whimsical smile.

“I think I may safely promise that,” said he. “I may add that your problem interests me, and that I shall be prepared to look into it. How shall I keep in touch with you?”

“The Carlton Club will find me. But in case of emergency, there is a private telephone call, ‘XX.31.’ ”

Holmes noted it down and sat, still smiling, with the open memorandum-book upon his knee.

“The Baron’s present address, please?”

“Vernon Lodge, near Kingston. It is a large house. He has been fortunate in some rather shady speculations and is a rich man, which naturally makes him a more dangerous antagonist.”

“Is he at home at present?”

“Yes.”

“Apart from what you have told me, can you give me any further information about the man?”

“He has expensive tastes. He is a horse fancier. For a short time he played polo at Hurlingham, but then this Prague affair got noised about and he had to leave. He collects books and pictures. He is a man with a considerable artistic side to his nature. He is, I believe, a recognized authority upon Chinese pottery and has written a book upon the subject.”

“A complex mind,” said Holmes. “All great criminals have that. My old friend Charlie Peace was a violin virtuoso. Wainwright was no mean artist. I could quote many more. Well, Sir James, you will inform your client that I am turning my mind upon Baron Gruner. I can say no more. I have some sources of information of my own, and I dare say we may find some means of opening the matter up.”

When our visitor had left us Holmes sat so long in deep thought that it seemed to me that he had forgotten my presence. At last, however, he came briskly back to earth.