But Rouletabille did not reply at all, and Koupriane wound up by demanding what was the matter with him.

“The matter is,” replied Rouletabille, unable longer to conceal his anguish, “that the poison continues.”

“Does that astonish you?” returned Koupriane.  “It doesn’t me.”

Rouletabille looked at him and shook his head.  His lips trembled as he said, “I know what you think.  It is abominable.  But the thing I have done certainly is more abominable still.”

“What have you done, then, Monsieur Rouletabille?”

“Perhaps I have caused the death of an innocent man.”

“So long as you aren’t sure of it, you would better not fret about it, my dear friend.”

“It is enough that the doubt has arisen,” said the reporter, “almost to kill me;” and he heaved so gloomy a sigh that the excellent Monsieur Koupriane felt pity for the lad.  He tapped him on the knee.

“Come, come, young man, you ought to know one thing by this time - ‘you can’t make omelettes without breaking eggs,’ as they say, I think, in Paris.”

Rouletabille turned away from him with horror in his heart.  If there should be another, someone besides Michael!  If it was another hand than his that appeared to Matrena and him in the mysterious night!  If Michael Nikolaievitch had been innocent!  Well, he would kill himself, that was all.  And those horrible words that he had exchanged with Natacha rose in his memory, singing in his ears as though they would deafen him.

“Do you doubt still?” he had asked her, “that Michael tried to poison your father?”

And Natacha had replied, “I wish to believe it!  I wish to believe it, for your sake, my poor boy.”  And then he recalled her other words, still more frightful now!  “Couldn’t someone have tried to poison my father and not have come by the window?” He had faced such a hypothesis with assurance then — but now, now that the poison continued, continued within the house, where he believed himself so fully aware of all people and things — continued now that Michael Nikolaievitch was dead — ah, where did it come from, this poison? - and what was it?  Pere Alexis would hurry his analysis if he had any regard for poor Rouletabille.

For Rouletabille to doubt, and in an affair where already there was one man dead through his agency, was torment worse than death.

When they arrived at police-headquarters, Rouletabille jumped from Koupriane’s carriage and without saying a word hailed an empty isvotchick that was passing.  He had himself driven back to Pere Alexis.  His doubt mastered his will; he could not bear to wait away.  Under the arch of Aptiekarski-Pereoulok he saw once more the man Koupriane had placed there with the order to bring him Alexis’s message.  The man looked at him in astonishment.  Rouletabille crossed the court and entered the dingy old room once more.  Pere Alexis was not there, naturally, engaged