When he advertised for a woman to help him in his experimental work, he did so, honestly because he judged a woman, especially “of mature years,” was of no particular use to anybody, or, if she did happen to be of use, she could easily be replaced. With an almost brutal frankness, he had said to himself: “If the experiment I make upon her should prove fatal, she will be the kind of human unit that is never missed.” But Diana was an unexpected sort of “unit.” Her independence, clear perception and courage were a surprise to him. Her “mature years” did not conceal from him the fact that she had once been charming to look at,--and one point about her which gave him especial pleasure was her complete resignation of any idea that she could have attraction for men at her age. He knew how loth even the oldest women are to let go this inborn notion of captivating or subjugating the male sex,--but Diana was wholesomely free from any touch of the “volatile spinster,”--and unlike the immortal Miss Tox in “Dombey and Son,” was not in the least prone to indulge in a dream of marriage with the first man who might pay her a kindly compliment. And his dread of the possible result of his first experimental essay upon her was perfectly genuine, while his relief at finding her none the worse for it was equally sincere. Looking at her now, and listening to her bright talk and to the soft ripple of her low, sweet laughter, his thoughts were very busy. She was his “subject;” a living subject bound by her signed agreement to be under his command and as much at his disposal as a corpse given over for anatomical purposes to a surgeon’s laboratory. He did not propose to have any pity upon her, even if at any time her condition should call for pity. His experiment must be carried out at all costs. He did not intend to have any more “heart” for her than the vivisector has for the poor animal whose throbbing organs he mercilessly probes;--but to-night he was conscious of a certain attraction about her for which he was not prepared. He was in a sense relieved when dinner was over, and when she and his mother left the room. As soon as they had gone he addressed Vasho: “Did you see?” The negro inclined his head, and his black lips parted in a smile. “It is the beginning!” said Dimitrius, meditatively. “But the end is far off!” Vasho made rapid signs with his fingers in the dumb alphabet. His words were: “The Master will perhaps be over-mastered!” Dimitrius laughed, and patted the man kindly on the shoulder. “Vasho, you are an oracle! How fortunate you are dumb! But your ears are keen,--keep them open!” Vasho nodded emphatically, and with his right hand touched his forehead and then his feet, signifying that from head to foot he was faithful to duty.