This man before her was deceiving her. He had some sinister motive in thus endeavouring to plant seeds of suspicion within her mind. It was plain that he was endeavouring in some way to secure his own ends. Those ends, however, were a complete and inexplicable mystery.
"I cannot see that my friendship for Mr. Fetherston can have any interest for you," she replied. "Let us talk of something else."
"But it has," he persisted. "You must never meet that man again—you hear! never—otherwise you will discover to your cost that my serious warning has a foundation only too solid; that he is your bitterest enemy posing as your most affectionate friend."
"I don't believe you, Dr. Weirmarsh!" she cried resentfully, springing to her feet. "I'll never believe you!"
"My dear young lady," the man exclaimed, "you are really quite unnerved to-night. The general was quite right. I will mix you a draught like the one you had before—perfectly innocuous—something to soothe those unstrung nerves of yours." And beneath his breath, as his cruel eyes twinkled, he added: "Something to bring reason to those warped and excited senses—something to sow within you suspicion and hatred of Walter Fetherston."
Then aloud he added, as he sprang to his feet: "Excuse me for a moment while I go and dispense it. I'll be back in a few seconds."
He left the room when, quick as lightning, Enid stretched forth her hand to the drawer of the writing-table into which she had seen the doctor toss the foreign letter he had been reading when she entered.
She drew it out, and scanned eagerly a dozen or so of the closely-written lines in Spanish.
Then she replaced it with trembling fingers, and, closing the drawer, sat staring straight before her—dumbfounded, rigid.
What was the mystery?