“O, you’re as bad as Furneaux,” cried Winter impatiently.  “Give it to me.  I must be off.  The hour is long past midnight and I have a busy day before me tomorrow.”

Back in the seclusion of his own rooms, Theydon debated the question whether or not he should endeavor to communicate with Forbes again that night.  Somehow it seemed to him that Forbes would be most concerned at hearing of the gray car.  And what of the ivory skull?

Suppose he knew of that!  But a certain revulsion of feeling had come over Theydon since the sheer brutality of the murder had been revealed.  He failed to see now why he should be so solicitous for Forbes’s welfare.  No matter what private purpose the man might serve by concealing his visit to Mrs. Lester, it ought to give way before the paramount importance of tracking a pitiless and callous criminal.

So Theydon hardened his heart and went to bed, and, being sound in mind and constitution, slept like a just man wearied.  Nevertheless, the last thing he saw before the curtain fell on his tired brain was an ivory skull dancing in the darkness.

Greatly as the many problems attached to Mrs. Lester’s death bewildered him, he would have been even more perplexed if he had overheard the conversation between Winter and Furneaux when they entered a taxi and gave Scotland Yard as their destination.

“Look here, Charles,” began Winter firmly; but the other stayed him with a clutch of thin, nervous fingers on an arm strong enough to fell an ox.

“Listen first, James—­ lecture me afterward,” pleaded Furneaux.  “I can’t help yielding to impulse.  And why should I strive to help it, anyhow?  How often has impulse led me to the goal when by every known rule of evidence I was completely beaten?  That is my plea.  That is why I brought that young fellow into No. 17, and watched the story of the tragedy reshaping itself in his imagination.  That is why, too, I spoke of the ivory skull.  Think what it means to one with the writer’s temperament.  The skull will never leave his mind’s eye.  It will focus and control his thoughts and actions.  And I feel it in my bones that only by keeping in touch with Mr. Francis Theydon shall we solve the Innesmore Mansions mystery.  I can’t explain why I think this, no more than the receiver of a wireless message can account for the waves of energy it picks up from the void and transmutes into the ordered sequences of the Morse code.  All I know is that when I am near him I am, as the children say, ‘warm,’ and when away from him, ‘cold.’  While he was examining the skull I was positively ‘hot,’ and was half inclined to treat him as a thought transference medium and order him sternly to speak....  No.  Be calm!  I even bid you be honest.  When have you, ever before, admitted an outsider to your councils?  And, if you make an exception of Theydon, why are you doing it?”

Winter bit the end off a cigar with a vicious jerk of his round head.  He struck a match and created such a volume of smoke that Furneaux coughed affectedly.