He paused, but his sister sat silent, with bent head and flushed cheeks. The little ebony cross rose and fell with her hurried breathings. "Dr. James M'Murdo O'Brien has, as you know, the offer of the physiological chair at Melbourne. He has been in Australia five years, and has a brilliant future before him. To-day he leaves us for Edinburgh, and in two months' time, he goes out to take over his new duties. You know his feeling towards you. It rests with you as to whether he goes out alone. Speaking for myself, I cannot imagine any higher mission for a woman of culture than to go through life in the company of a man who is capable of such a research as that which Dr. James M'Murdo O'Brien has brought to a successful conclusion." "He has not spoken to me," murmured the lady. "Ah, there are signs which are more subtle than speech," said her brother, wagging his head. "But you are pale. Your vasomotor system is excited. Your arterioles have contracted. Let me entreat you to compose yourself. I think I hear the carriage. I fancy that you may have a visitor this morning, Ada. You will excuse me now." With a quick glance at the clock he strode off into the hall, and within a few minutes he was rattling in his quiet, well-appointed brougham through the brick-lined streets of Birchespool. His lecture over, Professor Ainslie Grey paid a visit to his laboratory, where he adjusted several scientific instruments, made a note as to the progress of three separate infusions of bacteria, cut half-a-dozen sections with a microtome, and finally resolved the difficulties of seven different gentlemen, who were pursuing researches in as many separate lines of inquiry. Having thus conscientiously and methodically completed the routine of his duties, he returned to his carriage and ordered the coachman to drive him to The Lindens. His face as he drove was cold and impassive, but he drew his fingers from time to time down his prominent chin with a jerky, twitchy movement. The Lindens was an old-fashioned, ivy-clad house which had once been in the country, but was now caught in the long, red-brick feelers of the growing city. It still stood back from the road in the privacy of its own grounds. A winding path, lined with laurel bushes, led to the arched and porticoed entrance. To the right was a lawn, and at the far side, under the shadow of a hawthorn, a lady sat in a garden-chair with a book in her hands. At the click of the gate she started, and the Professor, catching sight of her, turned away from the door, and strode in her direction. "What! won't you go in and see Mrs. Esdaile?" she asked, sweeping out from under the shadow of the hawthorn.