"Oh dear, oh dear," he cried, "all the liquid has escaped. What shall I do?" and he wrung his hands in despair. "What on earth is the matter?" said Roux, running up to the assistance of his friend. "Are you hurt?" "No, no," said Paul testily, "don't mind me--it's the bottle," he cried. "It is a priceless treasure. It contained a poison from Japan, and some of the contents have been stolen." "Well, surely that is not of much consequence," said Roux. "Not of much consequence, you idiot? Don't you see that this contained the liquid which the fellow injected into Delapine's arm? I understand it all now," said Paul. "Tell me quickly, have you found out who could have stolen the liquid? What was the rascal like, do you know his name?" asked Roux. "I am sorry I forgot to ask Dr. Riche about him." "Still, if he knows he will tell us," answered Paul, anxious to conceal his thoughts, but with such a look of hesitancy and in such a strange voice that Roux felt certain that Paul knew a great deal more than he cared to admit. "I believe you know who did it, but don't want to tell me. Confess now, Paul." Paul's mind became a whirl of conflicting emotions. If he told Roux, the latter would have to put it in his report and communicate with the Parquet. And then there would be the greatest trouble. He stammered and hesitated while his face turned perfectly scarlet. "Come now, out with it," said Roux impatiently. "I cannot, I cannot," replied Paul, "please do not press me, but Dr. Villebois will tell you better than I can." "Is Villebois on the telephone?" "Yes, of course." Roux ran over to the telephone and called up 26-230. "Hullo, is that you, Dr. Villebois?" "Yes, who are you?" "Dr. Roux is speaking. I want to know if you have any clue as to the man who injected the fluid into Professor Delapine's arm?" "No," came the reply, "we have no actual proof as to who did it, but we believe that the would-be assassin was the same individual who set fire to Riche's room." "What makes you think that?" "Because by setting fire to Riche's room it would draw the people in the house upstairs, so that the fellow could not be interrupted in his ghastly work." "I think that is quite a reasonable explanation, but what a pity the scoundrel escaped," said Roux. "Never mind, we shall find him yet," replied Villebois. "May we come and see you at once?" asked Roux. "It is most important." "Certainly, I will wait in for you; au revoir," and the telephone ceased. Roux at once informed Paul what Dr. Villebois had told him. "My God, what a scoundrel," said Paul. "But the motive--the motive?" "I am quite in the dark as to his motive, anyhow there can be no doubt as to the course we have to pursue," said Roux. "Let us go together to Villebois's house, and we will examine the professor and draw up a report together."