The information supplied by Mr. Samuel Wilkins, so far from dispelling the cloud of mystery that hung over the Blackmore case, only enveloped it in deeper obscurity, so far as I was concerned. The new problem that Thorndyke offered for solution was a tougher one than any of the others. He proposed that I should identify and give a name to this mysterious woman. But how could I? No woman, excepting Mrs. Wilson, had been mentioned in connection with the case. This new dramatis persona had appeared suddenly from nowhere and straightway vanished without leaving a trace, excepting the two or three beads that we had picked up in Jeffrey's room.  
Nor was it in the least clear what part, if any, she had played in the tragedy. The facts still pointed as plainly to suicide as before her appearance. Jeffrey's repeated hints as to his intentions, and the very significant preparations that he had made, were enough to negative any idea of foul play. And yet the woman's presence in the chambers at that time, the secret manner of her arrival and her precautions against recognition, strongly suggested some kind of complicity in the dreadful event that followed.
 
But what complicity is possible in the case of suicide? The woman might have furnished him with the syringe and the poison, but it would not have been necessary for her to go to his chambers for that purpose. Vague ideas of persuasion and hypnotic suggestion floated through my brain; but the explanations did not fit the case and the hypnotic suggestion of crime is not very convincing to the medical mind. Then I thought of blackmail in connection with some disgraceful secret; but though this was a more hopeful suggestion, it was not very probable, considering Jeffrey's age and character.
 
And all these speculations failed to throw the faintest light on the main question: "Who was this woman?"
 
A couple of days passed, during which Thorndyke made no further reference to the case. He was, most of the time, away from home, though how he was engaged I had no idea. What was rather more unusual was that Polton seemed to have deserted the laboratory and taken to outdoor pursuits. I assumed that he had seized the opportunity of leaving me in charge, and I dimly surmised that he was acting as Thorndyke's private inquiry agent, as he seemed to have done in the case of Samuel Wilkins.
 
On the evening of the second day Thorndyke came home in obviously good spirits, and his first proceedings aroused my expectant curiosity. He went to a cupboard and brought forth a box of Trichinopoly cheroots. Now the Trichinopoly cheroot was Thorndyke's one dissipation, to be enjoyed only on rare and specially festive occasions; which, in practice, meant those occasions on which he had scored some important point or solved some unusually tough problem. Wherefore I watched him with lively interest.
 
"It's a pity that the 'Trichy' is such a poisonous beast," he remarked, taking up one of the cheroots and sniffing at it delicately. "There is no other cigar like it, to a really abandoned smoker." He laid the cigar back in the box and continued: "I think I shall treat myself to one after dinner to celebrate the occasion."
 
"What occasion?" I asked.
 
"The completion of the Blackmore case. I am just going to write to Marchmont advising him to enter a caveat."
 
"Do you mean to say that you have discovered a flaw in the will, after all?"
 
"A flaw!" he exclaimed. "My dear Jervis, that second will is a forgery."
 
I stared at him in amazement; for his assertion sounded like nothing more or less than arrant nonsense.
 
"But the thing is impossible, Thorndyke," I said. "Not only did the witnesses recognize their own signatures and the painter's greasy finger-marks, but they had both read the will and remembered its contents."
 
"Yes; that is the interesting feature in the case. It is a very pretty problem. I shall give you a last chance to solve it. To-morrow evening we shall have to give a full explanation, so you have another twenty-four hours in which to think it over. And, meanwhile, I am going to take you to my club to dine. I think we shall be pretty safe there from Mrs. Schallibaum."
 
He sat down and wrote a letter, which was apparently quite a short one, and having addressed and stamped it, prepared to go out.
 
"Come," said he, "let us away to 'the gay and festive scenes and halls of dazzling light.' We will lay the mine in the Fleet Street pillar box. I should like to be in Marchmont's office when it explodes."
 
"I expect, for that matter," said I, "that the explosion will be felt pretty distinctly in these chambers."
 
"I expect so, too," replied Thorndyke; "and that reminds me that I shall be out all day to-morrow, so, if Marchmont calls, you must do all that you can to persuade him to come round after dinner and bring Stephen Blackmore, if possible. I am anxious to have Stephen here, as he will be able to give us some further information and confirm certain matters of fact."
 
I promised to exercise my utmost powers of persuasion on Mr. Marchmont which I should certainly have done on my own account, being now on the very tiptoe of curiosity to hear Thorndyke's explanation of the unthinkable conclusion at which he had arrived—and the subject dropped completely; nor could I, during the rest of the evening, induce my colleague to reopen it even in the most indirect or allusive manner.
 
Our explanations in respect of Mr. Marchmont were fully realized; for, on the following morning, within an hour of Thorndyke's departure from our chambers, the knocker was plied with more than usual emphasis, and, on my opening the door, I discovered the solicitor in company with a somewhat older gentleman. Mr. Marchmont appeared somewhat out of humour, while his companion was obviously in a state of extreme irritation.
 
"How d'you do, Dr. Jervis?" said Marchmont as he entered at my invitation. "Your friend, I suppose, is not in just now?"
 
"No; and he will not be returning until the evening."
 
"Hm; I'm sorry. We wished to see him rather particularly. This is my partner, Mr............