Professor Ainslie Grey was at that time forty-three years of age--nearly twelve years older than his sister. His career had been a brilliant one. At Edinburgh, at Cambridge, and at Vienna he had laid the foundations of his great reputation, both in physiology and in zoology. His pamphlet, "On the Mesoblastic Origin of Excitomotor Nerve Roots," had won him his fellowship of the Royal Society; and his researches, "Upon the Nature of Bathybius, with some Remarks upon Lithococci," had been translated into at least three European languages. He had been referred to by one of the greatest living authorities as being the very type and embodiment of all that was best in modern science. No wonder, then, that when the commercial city of Birchespool decided to create a medical school, they were only too glad to confer the chair of physiology upon Mr. Ainslie Grey. They valued him the more from the conviction that their class was only one step in his upward journey, and that the first vacancy would remove him to some more illustrious seat of learning. In person he was not unlike his sister. The same eyes, the same contour, the same intellectual forehead. His lips, however, were firmer, and his long, thin lower jaw was sharper and more decided. He ran his finger and thumb down it from time to time, as he glanced over his letters. "Those maids are very noisy," he remarked, as a clack of tongues sounded in the distance. "It is Sarah," said his sister; "I shall speak about it." She had handed over his coffee-cup, and was sipping at her own, glancing furtively through her narrowed lids at the austere face of her brother. "The first great advance of the human race," said the Professor, "was when, by the development of their left frontal convolutions, they attained the power of speech. Their second advance was when they learned to control that power. Woman has not yet attained the second stage." He half closed his eyes as he spoke, and thrust his chin forward, but as he ceased he had a trick of suddenly opening both eyes very wide and staring sternly at his interlocutor. "I am not garrulous, John," said his sister. "No, Ada; in many respects you approach the superior or male type." The Professor bowed over his egg with the manner of one who utters a courtly compliment; but the lady pouted, and gave an impatient little shrug of her shoulders. "You were late this morning, John," she remarked, after a pause. "Yes, Ada; I slept badly. Some little cerebral congestion, no doubt due to over-stimulation of the centres of thought. I have been a little disturbed in my mind." His sister stared across at him in astonishment. The Professor's mental processes had hitherto been as regular as his habits. Twelve years' continual intercourse had taught her that he lived in a serene and rarefied atmosphere of scientific calm, high above the petty emotions which affect humbler minds.