The detective arose in astonishment and stared at the slight figure before him inquiringly; he knew the man too well to dispute any assertion he might make.
“Who is the murderer?” he asked.
The Thinking Machine closed the door and the spring lock clicked.
“That man there,” he remarked calmly, turning on Osaka.
For one brief instant there was a pause and silence; then the detective advanced upon the Japanese with hand outstretched. The agile Osaka leapt suddenly, as a snake strikes; there was a quick, fierce struggle and Detective Mallory sprawled on the floor. There had been just a twist of the wrist—a trick of jiu jitsu—and Osaka had flung himself at the locked door. As he fumbled there Hatch, deliberately and without compunction, raised a chair and brought it down on his head. Osaka sank down without a sound.
It was an hour before they brought him around again. Meanwhile the detective had patted and petted half a dozen suddenly acquired bruises, and had then searched Osaka. He found nothing to interest him save a small bottle. He uncorked it and started to smell it when The Thinking Machine snatched it away.
“You fool, that’ll kill you!” he exclaimed.
Osaka sat, lashed hand and foot to a chair, in Detective Mallory’s office—so placed by the detective for safe keeping. His face was no longer expressionless; there were fear and treachery and cunning there. So he listened, perforce, to the statement of the case by The Thinking Machine who leaned back in his chair, squinting steadily upward and with his long, slender fingers pressed together.
“Two and two make four, not some times but all the time,” he began at last as if disputing some previous assertion. “As the figure two, wholly disconnected from any other, gives small indication of a result, so is an isolated fact of little consequence. Yet that fact added to another, and the resulting fact added to a third, and so on, will give a final result. That result, if every fact is considered, must be correct. Thus any problem may be solved by logic; logic is inevitable.
“In this case the facts, considered singly, might have been compatible with either a natural death, suicide, or murder—considered together they proved murder. The climax of this proof was the removal of the maker’s name from the dead man’s shoes, and a fact strongly contributory was the attempt to destroy the identity of the boat. A subtle mind lay back of it all.”
“I so regarded it,” said Detective Mallory. “I was confident of murder until the Medical Examiner—”
“We prove a murder,” The Thinking Machine went on serenely. “The method? I was with Dr. Clough at the autopsy. There was no shot, or knife wound, no poison in the stomach. Knowing there was murder I sought further. Then I found the method in a slight, jagged wound on the left arm. It had been covered with court plaster. The heart showed constriction without apparent cause, and while Dr. Clough examined it I took off this court plaster. Its odour, an unusual one, told me that poison had been transfused into the blood through the wound. So two and two had made four.
“Then—what poison? A knowledge of botany aided me. I recognized faintly the trace of an odour of an herb which is not only indigenous to, but grows exclusively in Japan. Thus a Japanese poison. Analysis later in my laboratory proved it was a Japanese poison, virulent, and necessarily slow to act unless it is placed directly in an artery. The poison on the court plaster and that you took from Osaka are identical.”
The scientist uncorked the bottle and permitted a single drop of a green liquid to fall on his handkerchief. He allowed a minute or more for evaporation then handed it to Detective Mallory who sniffed at it from a respectful distance. Then The Thinking Machine produced the bit of court plaster he had taken from the dead man’s arm, and again the detective sniffed.
“The same,” the scientist resumed as he touched a lighted match to the handkerchief and watched it crumble to ashes, “and so powerful that in its pure state mere inhalation is fatal. I permitted Dr. Clough to make public his opinion—heart failure—after the autopsy for obvious reasons. It would reassure the murderer for instance if he saw it printed, and besides Dudley did die from heart failure; the poison caused it.
“Next came identification. Mr. Hatch learned that no French war ship had been within hundreds of miles of Boston for months. The one seen by Captain Barber might have been one of our own. This man was supposed to be a French naval officer, and had been dead less than eight hours. Obviously he did not come from a ship of his own country. Then from where?
“I know nothing of uniforms, yet I examined the insignia on the arms and shoulders closely after which I consulted my encyclopaedia. I learned that while the uniform was more French than anything else it was really the uniform of no country, because it was not correct. The insignia were mixed.
“Then what? There were several possibilities, among them a fancy dress ball was probable. Absolute accuracy would not be essential there. Where had there been a fancy dress ball? I trusted to the newspapers to tell me that. They did. A short dispatch from a place on the North Shore stated that on the night before the man was found dead there had been a fancy dress ball at the Langham Dudley estate.
“Now it is as necessary to remember every fact in solving a problem as it is to consider every figure in arithmetic. Dudley! Here was the ‘D’ tattooed on the dead man’s hand. ‘Who’s Who’ showed that Langham Dudley married Edith Marston Belding. Here was the ‘E. M. B.’ on the handkerchief in the boat. Langham Dudley was a ship owner, had been a sailor, was a millionaire. Possibly this was his own boat built in France.”
Detective Mallory was staring into the eyes of The Thinking Machine in frank admiration; Osaka to whom the narrative had thus far been impersonal, gazed, gazed as if fascinated. Hutchinson Hatch, reporter, was drinking in every word greedily.
“We went to the Dudley place,” the scientist resumed after a moment. “This Japanese opened the door. Japanese poison! Two and two were still making four. But I was first interested in Mrs. Dudley. She showed no agitation and told me frankly that she placed the court plaster on her husband’s arm, and that it came from her room. There was instantly a doubt as to her connection with the murder; her immediate frankness aroused it.
“Finally, with my hand on her pulse—which was normal—I told her as brutally as I could that her husband had been murdered. Her pulse jumped frightfully and as I told her the cause of death it wavered, weakened and she fainted. Now if she had known her husband were dead—even if she had killed him—a mere statement of his death would not have caused that pulse. Further I doubt if she could have disposed of her husband’s body in the motor boat. He was a large man and the manner of her dress even, was against this. Therefore she was innocent.
“And then? The Japanese, Osaka, here. I could see the door of the boat house from the room where we were. Mrs. Dudley asked Osaka if Mr. Dudley’s boat wase in the house. He said he didn’t know. Then she sent him to see. He returned and said the boat was not there, yet he had not gone to the boat house at all. Ergo, he knew the boat was not there. He may have learned it from another servant, still it was a point against him.”
Again the scientist paused and squinted at the Japanese. For a moment Osaka withstood the gaze, then his beady eyes shifted and he moved uncomfortably.
“I tricked Osaka into coming here by a ludicrously simple expedient,” The Thinking Machine went on steadily. “On the train I asked if he knew just how Mrs. Dudley got the body of her husband into the boat. Remember at this point he was not supposed to know that the body had been in a boat at all. He said he didn’t know and by that very answer admitted that he knew the body had been placed in the boat. He knew because he put it there himself. He didn’t merely throw it in the water because he had sense enough to know if the tide didn’t take it out it would rise, and possibly be found.
“After the slight injury Mr. Dudley evidently wandered out toward the boat house. The poison was working, and perhaps he fell. Then this man removed all identifying marks, even to the name in the shoes, put the body in the boat and