“The skull—­ the ivory skull!” put in Furneaux.

For an instant an expression of annoyance flitted across the chief inspector’s good-humored face.  Theydon did not see it, because Furneaux’s odd-sounding words caused him to look with astonishment at the man who uttered them.

“An ivory skull!” he cried.  “What has an ivory skull to do with the murder of Mrs. Lester?”

“We cannot even begin to guess at its meaning yet,” said Winter, who, after one fierce glance at his colleague, had recovered his poise.  “That is why I did not mention it.  I hate the introduction of bizarre features into an inquiry of this sort.  But, now that the thing has been spoken of, I may as well state that when the medical examination was being made at the mortuary a tiny skull, not bigger than a pea, and made of ivory, was found inside Mrs. Lester’s underbodice.  The curious fact is that it was loose.  Had it been attached to a cord, or secured in some way, one might regard it as a charm or amulet, because some women, even in the London of today, are not beyond the reach of superstition in such matters.  But, as I say, it was not safeguarded at all, so we may reasonably assume that it was not carried habitually.  Of course, Furneaux readily evolved a far-fetched theory that it is a sign, or symbol, and was thrust out of sight among the clothing on the dead woman’s breast by the man who killed her.  But that is idle guesswork.  We of the Yard seldom pay heed to theatrical notions of that kind.  Here is the article.  I don’t mind letting you see it, but kindly remember that its existence must not be made known.  I must have your promise not to mention it to a living creature.”

Furneaux chuckled derisively.

“That is precisely the sort of thing anybody would say who attached no importance to the exhibit,” he piped.

Winter so nearly lost his temper that he repressed the retort on his lips.  He contented himself, however, with producing a small white object from his waistcoat pocket, and handed it to Theydon.  It was a bit of ivory, hollow, and very light, and fashioned as a skull.

Yet, it was by no means an ordinary creation.  The artist who fashioned it had gratified a morbid taste by imparting to the eyeless sockets and close-set rows of teeth a malign and threatening grin.  Wickedness, not death, was suggested, but the craftsmanship was faultless.  A collector would have paid a large sum for it, while the average citizen would refuse to have it in his house.

“What an extraordinary thing,” said Theydon, turning the curio round and round in his fingers.

“It’s wonderfully well carved,” agreed Winter.

“From that point of view it’s a masterpiece, but what I meant was the astounding fact that it should have been discovered on the dead woman’s body.  Was it placed over her heart?”

“Why do you ask that?” came the sharp demand.

“Because—­ if it is a token of some vendetta—­ if the murderer wished to signify that he had glutted his vengeance—­”