“You are satisfied, Mademoiselle, but the Law is not,” Hanaud returned. “Boris Waberski expected a legacy. Boris Waberski needed money immediately, as the first of the two letters which he wrote to Monsieur Frobisher’s firm clearly shows. Boris Waberski had a motive.” He looked from one to the other of his audience with a nod to drive the point home. “Motives, no doubt, are signposts rather difficult to read, and if one reads them amiss, they lead one very wide astray. Granted! But you must look for your signposts all the same and try to read them aright. Listen again to the Professor of Medicine in the University of Edinburgh! He is as precise as a man can be.”
Hanaud’s eyes fell again upon the description of Figure F in the treatise still open upon the table in front of him.
“The arrow was the best specimen of a poison arrow which he had ever come across. The poison paste was thickly and smoothly spread over the arrow head and some inches of the shaft. The arrow was unused and the poison fresh, and these poisons retain their energy for many, many years. I tell you that if this book and this arrow were handed over to Jean Cladel, Herbalist, Jean Cladel could with ease make a solution in alcohol which injected from a hypodermic needle, would cause death within fifteen minutes and leave not one trace.”
“Within fifteen minutes?” Betty asked incredulously, and from the armchair against the wall, where Ann Upcott had once more seated herself, there broke a startled exclamation.
“Oh!” she cried, but no one took any notice of her at all. Both Jim and Betty had their eyes fixed upon Hanaud, and he was altogether occupied in driving his argument home.
“Within fifteen minutes? How do you know?” cried Jim.
“It is written here, in the book.”
“And where would Jean Cladel have learnt to handle the paste with safety, how to prepare the solution?” Jim went on.
“Here! Here! Here!” answered Hanaud, tapping with his knuckles upon the treatise. “It is all written out here—experiment after experiment made upon living animals and the action of the poison measured and registered by minutes. Oh, given a man with a working knowledge of chemicals such as Jean Cladel must possess, and the result is certain.”
Betty Harlowe leaned forward again over the book and Hanaud turned it half round between them, so that both, by craning their heads, could read. He turned the pages back to the beginning and passed them quickly in review.
“See, Mademoiselle, the time tables. Strophanthus constricts the muscles of the heart like digitalis, only much more violently, much more swiftly. See the contractions of the heart noted down minute after minute, until the moment of death and all—here is the irony!—so that by means of these experiments, the poison may be transformed into a medicine and the weapon of death become an agent of life—as in good hands, it has happened.” Hanaud leaned back and contemplated Betty Harlowe between his half-closed eyes. “That is wonderful, Mademoiselle. What do you think?”
Betty slowly closed the book.
“I think, Monsieur Hanaud,” she said, “it is no less wonderful that you should have studied this book so thoroughly during the half-hour you waited for us here this morning.”
It was Hanaud’s turn to change colour. The blood mounted into his face. He was for a second or two quite disconcerted. Jim once more had a glimpse of the secret duel and rejoiced that this time it was Hanaud, the great Hanaud, who was scratched.
“The study of poisons is particularly my work,” he answered shortly. “Even at the Sûrété we have to specialise nowadays,” and he turned rather quickly towards Frobisher. “You are thoughtful, Monsieur?”
Jim was following out his own train of thought.
“Yes,” he answered. Then he spoke to Betty.
“Boris Waberski had a latchkey, I suppose?”
“Yes,” she replied.
“He took it away with him?”
“I think so.”
“When are the iron gates locked?”
“It is the last thing Gaston does before he goes to bed.”
Jim’s satisfaction increased with every answer he received.
“You see, Monsieur Hanaud,” he cried, “all this while we have been leaving out a question of importance. Who put this book back upon its shelf? And when? Yesterday at noon the space was empty. This morning it is filled. Who filled it? Last night we sat in the garden after dinner behind the house. What could have been easier than for Waberski to slip in with his latchkey at some moment when the court was empty, replace the book and slip out again unnoticed? Why—”
A gesture of Betty’s brought him to a halt.
“Unnoticed? Impossible!” she said bitterly. “The police have a sergent-de-ville at our gates, night and day.”
Hanaud shook his head.
“He is there no longer. After you were good enough to answer me so frankly yesterday morning the questions it was my duty to put to you, I had him removed at once.”
“Why, that’s true,” Jim exclaimed joyfully. He remembered now that when he had driven up with his luggage from the hotel in the afternoon, the street of Charles-Robert had been quite empty. Betty Harlowe stood taken aback by her surprise. Then a smile made her face friendly; her eyes danced to the smile, and she dipped to the detective a little mock curtsy. But her voice was warm with gratitude.
“I thank you, Monsieur. I did not notice yesterday that the man had been removed, or I should have thanked you before. Indeed I was not looking for so much consideration at your hands. As I told my friend Jim, I believed that you went away thinking me guilty.”
Hanaud raised a hand in protest. To Jim it
