“Where?  Where exactly did you find it?” the other insisted.

Quest was standing very still, his manner more reserved even than usual, his eyes studying the Professor, weighing every spoken word.

“I found it in a hut,” he said, “hidden in a piano box.  I found there, also, a creature—­a human being, I must call him—­in a state of captivity.”

“Hidden in a piano box?” the Professor repeated wonderingly.  “Why, you mean in Hartoo’s sleeping box, then?”

“If Mr. Hartoo is the gentleman who tried to club me, you are right,” Quest admitted.  “Mr. Ashleigh, before we go any further I must ask you for an explanation as to the presence of that person in your grounds!”

The Professor hesitated for a moment.  Then he slowly crossed the room, opened the drawer of a small escritoire, and drew out a letter.

“You have heard of Sir William Raysmore, the President of the Royal Society?” he asked.

Quest nodded.

“This letter is from him,” the Professor continued.  “You had better read it.”

The criminologist read it aloud.  Lenora looked over his shoulder:—­

    “To Professor Edgar Ashleigh, New York.

    “My dear Professor,

“Your communication gratifies and amazes me.  I can say no more.  It fell to your lot to discover the skeleton of the anthropoid, a marvellous thing, in its way, and needing only its corollary to form the greatest discovery since the dark ages.  Now you tell me that in the person of Hartoo, the last of the Inyamo Race of South America, you have found that corollary.  You have supplied the missing link.  You are in a position to give to the world a definite and logical explanation of the evolution of man.  Let me give you one word of warning, Professor, before I write you at greater length on this matter.  Anthropologists are afflicted more, even, than any other race of scientific men, with jealousy.  Guard your secret well, lest the honour of this discovery should be stolen from you.

    “William Raysmore.”

[Illustration:  Quest and Lenora receive the message from Laura.]

[Illustration:  Quest is surprised at finding the stolen necklace in the black box.]

The Professor nodded deliberately as Quest finished the letter.

“Now, perhaps, you can understand,” he said, “why it was necessary to keep Hartoo absolutely hidden.  In a month’s time my papers will be ready.  Then I shall electrify the world.  I shall write not a new page but a new volume across the history of science.  I shall—­”

The door was suddenly thrown open.  Craig sprang in, no longer the self-contained, perfect man-servant, but with the face of some wild creature.  His shout was one almost of agony.