“I can refuse until I stand in the witness-box!” replied Cumberly, turning, a wry smile upon his face.

“With the result,” interposed Max, “that the ends of justice might be defeated, and the wrong man hanged!”

“True,” said Cumberly; “I am splitting hairs.  It is distinctly a breach of professional etiquette, nevertheless, and I cannot disguise the fact from myself.  However, since the knowledge will never go any further, and since tremendous issues are at stake, I will give you the name of my opium patient.  It is Sir Brian Malpas!”

“I am much indebted to you, Dr. Cumberly,” said Max; “a thousand thanks;” but in his eyes there was a far-away look.  “Malpas—­Malpas!  Where in this case have I met with the name of Malpas?”

“Inspector Dunbar may possibly have mentioned it to you in reference to the evidence of Mr. John Exel, M. P. Mr. Exel, you may remember"...

“I have it!” cried Max; “Nom d’un nom!  I have it!  It was from Sir Brian Malpas that he had parted at the corner of Victoria Street on the night of the murder, is it not so?”

“Your memory is very good, M. Max!”

“Then Mr. Exel is a personal friend of Sir Brian Malpas?

“Excellent!  Kismet aids me still!  I come to you hoping that you may be acquainted with the constitution of Mrs. Leroux, but no! behold me disappointed in this.  Then—­morbleu! among your patients I find a possible client of the opium syndicate!”

“What!  Malpas?  Good God!  I had not thought of that!  Of course, he must retire somewhere from the ken of society to indulge in these opium orgies"...

“Quite so.  I have hopes.  Since it would never do for Sir Brian Malpas to know who I am and what I seek, a roundabout introduction is provided by kindly Providence—­Ah! that good little angel of mine!—­in the person of Mr. John Exel, M. P.”

“I will introduce you to Mr. Exel with pleasure.”

“Eh bien!  Let it be arranged as soon as possible,” said M. Max.  “To Mr. John Exel I will be, as to Miss Ryland (morbleu!  I hate me!) and Miss Cumberly (pardieu!  I loathe myself!), M. Gaston!  It is ten o’clock, and already I hear your first patient ringing at the front-door bell.  Good morning, Dr. Cumberly.”

Dr. Cumberly grasped his hand cordially.

“Good morning, M. Max!”

The famous detective was indeed retiring, when: 

“M.  Max!”

He turned—­and looked into the troubled gray eyes of Dr. Cumberly.

“You would ask me where is she—­Mrs. Leroux?” he said.  “My friend—­I may call you my friend, may I not?—­I cannot say if she is living or is dead.  Some little I know of the Chinese, quite a little; nom de dieu!...  I hope she is dead!"...

XXIV

OPIUM

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.