Her words surprised Duvall. He had given her a simple drug, the effect of which should have been to make her drowsy, to quiet her nerves. That she had not taken it, he of course did not know. His greatest fear had been that she would refuse to enter the cab with him. Now that she had done so, he was prepared to use even force, if necessary, to retain her in his custody until he had either obtained the evidence he desired, or forced from her a confession. What he particularly hoped to find was the seal with which the death's head impression had been made. He felt certain that, if this was the woman he sought, she would have this seal somewhere about her person. It was far too significant a bit of evidence to be left lying about at home.
But there was always the chance that this woman, who had been so instantly affected by the ghastly apparition on the screen, the significant words beneath it, might not, after all, be the right one, the one he sought. There was always the possibility that the real criminal, although present in the audience, had made no sign, and that his companion in the cab might be entirely innocent. As he had told Baker, it was a chance--a long chance, yet something seemed to say to him that he had made no mistake in taking it. Now, however, a new situation had arisen to upset his plans. His prisoner, instead of having been quieted by the drug he had administered, was apparently becoming more and more agitated and nervous every minute. Her groans, as she lay huddled up in the corner of the cab, puzzled him, filled him with vague alarm. Was it possible that she had a weak heart? Had the sedative he had given her, harmless as he knew the dose would be to a normal person, affected her in so unfavorable a way? He took her wrist in his hand, and felt her pulse. It was quick, indicative of nervous excitement, but certainly not weak.
"Oh--doctor, doctor, won't you _please_ give me something to make me feel a little better?" the woman gasped. "It's my heart, I tell you. I--I can't breathe. I'm suffocating. I must have something at once--some aromatic spirits of ammonia--some brandy--anything, to make me feel a little better."
Her earnestness, her trembling voice, her excited manner, all served to convince Duvall that his companion was really in need of a stimulant of some sort. He decided to humor her. A dose of aromatic spirits, he reflected, could do no harm, and would doubtless serve to lessen her excitement. He leaned out, and directed the driver of the cab to stop at the nearest drug store.