Professor Ainslie Grey had not come down to breakfast at the usual hour. The presentation chiming-clock which stood between the terracotta busts of Claude Bernard and of John Hunter upon the dining-room mantelpiece had rung out the half-hour and the three-quarters. Now its golden hand was verging upon the nine, and yet there were no signs of the master of the house.

It was an unprecedented occurrence. During the twelve years that she had kept house for him, his youngest sister had never known him a second behind his time. She sat now in front of the high silver coffeepot, uncertain whether to order the gong to be resounded or to wait on in silence. Either course might be a mistake. Her brother was not a man who permitted mistakes.

Miss Ainslie Grey was rather above the middle height, thin, with peering, puckered eyes, and the rounded shoulders which mark the bookish woman. Her face was long and spare, flecked with colour above the cheek-bones, with a reasonable, thoughtful forehead, and a dash of absolute obstinacy in her thin lips and prominent chin. Snow-white cuffs and collar, with a plain dark dress, cut with almost Quaker-like simplicity, bespoke the primness of her taste. An ebony cross hung over her flattened chest. She sat very upright in her chair, listening with raised eyebrows, and swinging her eye-glasses backwards and forwards with a nervous gesture which was peculiar to her.

Suddenly she gave a sharp, satisfied jerk of the head, and began to pour out the coffee. From outside there came the dull thudding sound of heavy feet upon thick carpet. The door swung open, and the Professor entered with a quick, nervous step. He nodded to his sister, and seating himself at the other side of the table, began to open the small pile of letters which lay beside his plate.

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.