"Then I sat down and examined the syringe the nurse had given me. I found some substance remaining in it; made several tests, and discovered that it was a solution of curari or curarine." "Curari!" echoed Warren. "Curari, called variously 'curara, ourari, woorali', a deadly poison which leaves no trace when injected into the blood, or applied to an open wound or sore." Warren's eyes were fairly popping from his head. "And you think?" he gasped. "There is not a doubt in my mind but that Captain Lloyd was killed by an injection of a solution of curari," declared Ward, positively. "Every symptom, or rather, lack of symptoms, found at the autopsy points to its use. "Realizing what I had stumbled across," continued the doctor, "I hurried over to the office of the Sanitary Commission, and they told me there that the nurse, Mary Phelps, was at the Central Hospital. When I reached the hospital I found Miss Phelps just going off duty. She said that she had found that syringe tucked between the mattress and the headboard of Goddard's bed when she changed the sheets. She supposed I had dropped it there the night before." Ward ceased speaking, and in uncontrollable excitement Warren sprang to his feet and walked rapidly up and down the room. "This ought to help, and yet I cannot see--I cannot see," he muttered; then wheeled on Ward, who was watching him intently. "Come, Doctor, haven't you formed some theory which may give me a clue?" "I have," admitted Ward slowly. "It is one that may lead to very serious consequences. Curari is a poison that we Americans at present know little about. It is used by the South American Indians, who dip their arrow points in it. You can swallow a small dose of the poison and it will not hurt you. It is very difficult, if not impossible, to get this drug in this country. I only know one person who possesses a small quantity of the poison." "His name?" demanded Warren vehemently. "His name?" Then as Ward still hesitated, "Good God! man, do you realize that an innocent life may be sacrificed if you don't divulge his name!" "It is that which induced me to come to you to-night, Senator," said Ward reluctantly. "The only man I know who owns that drug is my preceptor, Doctor John Boyd." "Boyd!" shouted Warren. "Oh, preposterous!" "That is what I thought--at first." "Why, why, damn it, man!" exclaimed Warren. "Doctor John wouldn't do such a thing. He is just a hot-tempered, peppery old Southern----" "Exactly, sir, and has been accused of passing information through our lines. Time and again he has been threatened with arrest." Warren mopped his hot face; then dropped back into his chair. "Go ahead and explain your theory more definitely," he directed abruptly. "Doctor John is devoted to Miss Newton. I don't doubt he has assisted her on many occasions--" Ward checked his hasty speech. He did not wish to convince Warren that Nancy was a spy. _That_ would not be doing her a service.