"There is still another person—the fourth and last. This person possessed the marked symptoms of a common complaint—chills followed by fever. To this person I know Dr. Morse gave quinine."
"Well?" asked Fuller, eagerly.
"Chills and fever are indications of malaria—quinine is the invariable remedy for that complaint. And the light blue spots which you see in that smear of blood," pointing to the microscope, "are the germs of that same disease."
For a moment Fuller stood as though transfixed.
"You have the man!" he cried at last. "You have him beyond the shadow of a doubt! To think," in great admiration, "that he should be found out in such an unusual way. Why, it is one of the——" Here he paused, the enthusiasm died from his face, and he added slowly: "But suppose that blood clot was not left upon the drawer pull at the time you think. The man may have been in the library during the afternoon upon a perfectly legitimate errand."
But Ashton-Kirk shook his head.
"No," said he. "It happened last night about the time of the murder. If it had been earlier the blood would have been dry and hard to the core."
"I see," said Fuller. "I recall that you were surprised at its having retained any softness, even at that. But there is something else. If Miss Corbin is sure that Drevenoff did not descend from the third floor, after once going to his room, how do you account for his presence in the library at that time?"
"Miss Corbin was in position to see Drevenoff as he ascended the back stairs. She did not see him descend, and so concluded that he could not have done so. As a matter of fact he could have gained the first floor without any trouble by passing through some unoccupied rooms upon the third floor, and using the front or main staircase."
"Then that's it," declared Fuller. "He came down that way while the old servant was in the kitchen seeing to the coffee, did his work and went back to his room by the same route. But," with a puzzled look upon his face, "what in the world ever drew your attention to Drevenoff in the first place—that is, what made you think it might be his blood upon the handle of the drawer?"