Denise Ryland was lunching that day with Dr. Cumberly and his daughter at Palace Mansions; and as was usually the case when this trio met, the conversation turned upon the mystery.
 
“I have just seen Leroux,” said the physician, as he took his seat, “and I have told him that he must go for a drive to-morrow. I have released him from his room, and given him the run of the place again, but until he can get right away, complete recovery is impossible. A little cheerful company might be useful, though. You might look in and see him for a while, Helen?”
 
Helen met her father's eyes, gravely, and replied, with perfect composure, “I will do so with pleasure. Miss Ryland will come with me.”
 
“Suppose,” said Denise Ryland, assuming her most truculent air, “you leave off... talking in that... frigid manner... my dear. Considering that Mira... Leroux and I were... old friends, and that you... are old friends of hers, too, and considering that I spend... my life amongst... people who very sensibly call... one another... by their Christian names, forget that my name is Ryland, and call me... Denise!”
 
“I should love to!” cried Helen Cumberly; “in fact, I wanted to do so the very first time I saw you; perhaps because Mira Leroux always referred to you as Denise”...
 
“May I also avail myself of the privilege?” inquired Dr. Cumberly with gravity, “and may I hope that you will return the compliment?”
 
“I cannot... do it!” declared Denise Ryland, firmly. “A doctor ... should never be known by any other name than... Doctor. If I heard any one refer to my own... physician as Jack or... Bill, or Dick... I should lose ALL faith in him at once!”
 
As the lunch proceeded, Dr. Cumberly gradually grew more silent, seeming to be employed with his own thoughts; and although his daughter and Denise Ryland were discussing the very matter that engaged his own attention, he took no part in the conversation for some time. Then:
 
“I agree with you!” he said, suddenly, interrupting Helen; “the greatest blow of all to Leroux was the knowledge that his wife had been deceiving him.”
 
“He invited... deceit!” proclaimed Denise Ryland, “by his... criminal neglect.”
 
“Oh! how can you say so!” cried Helen, turning her gray eyes upon the speaker reproachfully; “he deserves—”
 
“He certainly deserves to know the real truth,” concluded Dr. Cumberly; “but would it relieve his mind or otherwise?”
 
Denise Ryland and Helen looked at him in silent surprise.
 
“The truth?” began the latter—“Do you mean that you know—where she is”...
 
“If I knew that,” replied Dr. Cumberly, “I should know everything; the mystery of the Palace Mansions murder would be a mystery no longer. But I know one thing: Mrs. Leroux's absence has nothing to do with any love affair.”
 
“What!” exclaimed Denise Ryland. “There isn't another man... in the case? You can't tell me”...
 
“But I DO tell you!” said Dr. Cumberly; “I ASSURE you.”
 
“And you have not told—Mr. Leroux?” said Helen incredulously. “You have NOT told him—although you know that the thought—of THAT is?”...
 
“Is practically killing him? No, I have not told him yet. For—would my news act as a palliative or as an irritant?”
 
“That depends,” pronounced Denise Ryland, “on the nature of... your news.”
 
“I suppose I have no right to conceal it from him. Therefore, we will tell him to-day. But although, beyond doubt, his mind will be relieved upon one point, the real facts are almost, if not quite, as bad.”
 
“I learnt, this morning,” he continued, lighting a cigarette, “certain facts which, had I been half as clever as I supposed myself, I should have deduced from the data already in my possession. I was aware, of course, that the unhappy victim—Mrs. Vernon—was addicted to the use of opium, and if a tangible link were necessary, it existed in the form of the written fragment which I myself took from the dead woman's hand.”...
 
“A link!” said Denise Ryland.
 
“A link between Mrs. Vernon and Mrs. Leroux,” explained the physician. “You see, it had never occurred to me that they knew one another.”...
 
“And did they?” questioned his daughter, eagerly.
 
“It is almost certain that they were acquainted, at any rate; and in view of certain symptoms, which, without giving them much consideration, I nevertheless had detected in Mrs. Leroux, I am disposed to think that the bond of sympathy which existed between them was”...
 
He seemed to hesitate, looking at his daughter, whose gray eyes were fixed upon him intently, and then at Denise Ryland, who, with her chin resting upon her hands, and her elbows propped upon the table, was literally glaring at him.
 
“Opium!” he said.
 
A look of horror began slowly to steal over Helen Cumberly's face; Denise Ryland's head commenced to sway from side to side. But neither woman spoke.
 
“By the courtesy of Inspector Dunbar,” continued Dr. Cumberly, “I have been enabled to keep in touch with the developments of the case, as you know; and he had noted as a significant fact that the late Mrs. Vernon's periodical visits to Scotland corresponded, curiously, with those of Mrs. Leroux to Paris. I don't mean in regard to date; although in one or two instances (notably Mrs. Vernon's last journey to Scotland, and that of Mrs. Le............