He had been prescribing a solution of arsenic, the dose increasing little by little toward the point of tolerance. Now, for the purpose of experiment, he ordered that the dose was to remain the same. And in order to impress his instructions upon the mind of Hamoud-bin-Said, he said to the Arab severely: "Remember, not one drop more!" CHAPTER XXXIII "Lilla! Lilla!" She appeared in the doorway of the study like a muse that David had summoned by an infallible conjuration. His day's work was over. He showed her what he had done. She leaned down beside the wheel chair to scan the pages; her fluffy, brown hair filled with the afternoon sunshine. And David, in the exhaustion following his labor, dreamily immersed his senses in the sight of her pale-brown cheek so close to his, in the persistent strangeness of her perfume, in the singular cadences of her voice that were always inspiring new harmonies, and in the caress of her cool, fragile hands that had drawn him back from death. "Is it good?" What he meant was, "Is it good enough to keep you from regrets?" She understood, pitied him the more, redoubled her tenderness. And this wan idyll of theirs, as nearly incorporeal as though she were indeed an ethereal visitor, took on a new pathos which was accentuated by the withering of the flowers in the garden, the first hints of the rigor of winter. He marveled at her self-immolation in this lonely house. He wondered how long such a state of things could last. Then, summoning back his new courage, he continued his combat against the unknown rivals, who, perhaps, had not yet revealed themselves to her, or else had thus far sent to her only ambiguous and subtle heralds of their coming--a breeze flavored with the past and promising an imitation of old transports, a cry of departing birds like a reassurance of the inevitable return, not only of the spring, but also of natural love. "What are you reading now?" he would ask her apprehensively; for so many books were replete with accounts of a different sort of union. Or, when she had gone to walk through the grounds at sunset, he, chained to his wheel chair, watched her departing figure with a sensation of dread, asking himself what thoughts would come to her out there, under the immense compulsion of the scarlet clouds. His fears, for lack of any other definite object, often veered toward her memories. She rejoined him at dusk, languid from that brief promenade, like those Eastern women whom Lawrence Teck had once described to her, or like one who is enervated by a fever stealthily creeping round one at the moment of tropical twilight. He saw her eyes misty with shadows which disappeared as she came forward into the lamplight. "Yes, she had been thinking of him." He suspected that she thought of "him" also in the night.