The invention of the mousetrap does not date from our days; as soon as societies, in forming, had invented any kind of police, that police invented mousetraps.

As perhaps our readers are not familiar with the slang of the Rue de Jerusalem, and as it is fifteen years since we applied this word for the first time to this thing, allow us to explain to them what is a mousetrap.

When in a house, of whatever kind it may be, an individual suspected of any crime is arrested, the arrest is held secret. Four or five men are placed in ambuscade in the first room. The door is opened to all who knock. It is closed after them, and they are arrested; so that at the end of two or three days they have in their power almost all the HABITUES of the establishment. And that is a mousetrap.

The apartment of M. Bonacieux, then, became a mousetrap; and whoever appeared there was taken and interrogated by the cardinal’s people. It must be observed that as a separate passage led to the first floor, in which d’Artagnan lodged, those who called on him were exempted from this detention.

Besides, nobody came thither but the three Musketeers; they had all been engaged in earnest search and inquiries, but had discovered nothing. Athos had even gone so far as to question M. de Treville--a thing which, considering the habitual reticence of the worthy Musketeer, had very much astonished his captain. But M. de Treville knew nothing, except that the last time he had seen the cardinal, the king, and the queen, the cardinal looked very thoughtful, the king uneasy, and the redness of the queen’s eyes donated that she had been sleepless or tearful. But this last circumstance was not striking, as the queen since her marriage had slept badly and wept much.

M de Treville requested Athos, whatever might happen, to be observant of his duty to the king, but particularly to the queen, begging him to convey his desires to his comrades.

As to d’Artagnan, he did not budge from his apartment. He converted his chamber into an observatory. From his windows he saw all the visitors who were caught. Then, having removed a plank from his floor, and nothing remaining but a simple ceiling between him and the room beneath, in which the interrogatories were made, he heard all that passed between the inquisitors and the accused.

The interrogatories, preceded by a minute search operated upon the persons arrested, were almost always framed thus: "Has Madame Bonacieux sent anything to you for her husband, or any other person? Has Monsieur Bonacieux sent anything to you for his wife, or for any other person? Has either of them confided anything to you by word of mouth?"