I wondered cynically what would happen if some one at that moment had appeared with the authenticated secret.  She continued to gaze at the books.  “There are plenty of rare chances for a young mining engineer in Peru without that.”

Apparently she was thinking of her son and his studies at the University as they affected his future career.

One could follow her thoughts, even, as they flitted from the treasure, to the books, to her son, and, finally, to the pretty girl for whom both he and Lockwood were struggling.

“We are a peculiar race,” she ruminated.  “We seldom intermarry with other races.  We are as proud as Senor Mendoza was of his Castilian descent, as proud of our unmixed lineage as any descendant of a ‘belted earl.’”

Senora de Moche made the remarks with a quiet dignity which left no doubt in my mind that the race feeling cut deeply.

She had risen now, and in place of the awesome fear of the curse and tragedy of the treasure her face was burning and her eyes flashed.

“Old Don Luis thought I was good enough to amuse his idle hours,” she cried.  “But when he saw that Alfonso was in love with his daughter, that she might return that love, then I found out bitterly that he placed us in another class, another caste.”

Kennedy had been following her closely, and I could see now that the cross-currents of superstition, avarice, and race hatred in the case presented a tangle that challenged him.

There was nothing more that we could extract from her just then.  She had remained standing, as a gentle reminder that the interview had already been long.

Kennedy took the hint.  “I wish to thank you for the trouble you have gone to,” he bowed, after we, too, had risen.  “You have told me quite enough to make me think seriously before I join in any such undertaking.”

She smiled enigmatically.  Whether it was that she had enjoyed penetrating our rather clumsy excuse for seeing her, or that she felt that the horror of the curse had impressed us, she seemed well content.

We bowed ourselves out, and, after waiting a few moments about the hotel without seeing Whitney anywhere, Craig called a car.

“They were right,” was his only comment.  “A most baffling woman, indeed.”

VII

THE ARROW POISON

Back again in the laboratory, Kennedy threw off his coat and plunged again into his investigation of the blood sample he had taken from the wound in Mendoza’s body.

We had scarcely been back half an hour before the door opened and Dr. Leslie’s perplexed face looked in on us.  He was carrying a large jar, in which he had taken away the materials which he wished to examine.

“Well,” asked Kennedy, pausing with a test-tube poised over a Bunsen burner, “have you found anything yet?  I haven’t had time to get very far with my own tests yet.”