She bent her head in mute obedience, thanking him with a smile. As she turned with a softly breathed “good-night” to Madame Dimitrius, the old lady drew her close and kissed her. “Bless you, my dear!” she said. “If you change in your looks, do not change in your heart!” “That can hardly be guaranteed,” said Dimitrius. Diana looked at him. “Can it not? But I will be my own guarantee,” she said. “I shall not change--not in love for my friends. Good-night!” As she left the room they both looked after her,--her figure had a supple, swaying grace of movement which was new and attractive, and in an impulse of something not unlike fear, Madame Dimitrius laid her hand entreatingly on her son’s arm. “What have you done to her, Féodor? What are you doing?” His eyes glittered with a kind of suppressed menace. “Nothing!” he answered. “Nothing, as yet! What I _shall_ do is another matter! I have begun--and I cannot stop. She is my subject,--I am like that old-world painter, who, in sheer devotion to his art, gave a slave poison, in order that he might be able to watch him die and so paint a death-agony accurately.” “Féodor!” She gave a little cry of terror. “Do not be afraid, mother mine! My task is an agony of birth--not death!--the travail of a soul reconstituting the atoms of its earthly habitation,--recharging with energy the cells of its brain--the work of a unit whose house of clay is beginning to crumble, and to whom I give the material wherewith to build it up again! It all depends, of course, on the unit’s own ability,--if you break a spider’s web, the mending of it depends on the spider’s industry, tenacity and constructive intelligence,--but, whatever happens, mark you!--_whatever_ happens, I have begun my experiment, and I must go on! I must go on to the very end,--no matter what that end may be!” She looked at him in wonder and appeal. “You will not,--you cannot be cruel, Féodor?” she said, in a voice which trembled with suppressed alarm. “You will not injure the poor woman who works for you so patiently, and who trusts you?” “How can I tell whether I shall or shall not injure her?” he demanded, almost fiercely. “Science accepts no half service. The ‘poor woman,’ as you call her, knows her risks and has accepted them. So far, no injury has been done. If I succeed, she will have cause to thank me for the secret I have wrenched from Nature,--should I fail, she will not complain very much of a little more hurried exit from a world, where, according to her own statement, she is alone and unloved.” Madame Dimitrius clasped and unclasped her delicate old hands nervously, and the diamonds in a ring she wore glittered scarcely more than the bright tears which suddenly fell from her eyes. Moved by a pang of remorse, he fell on his knees beside her.