For a time Sainte-Croix hesitated: at last he yielded to the taunts of
his companion, who accused Frenchmen of showing too much honour in their
crimes, of allowing themselves to be involved in the ruin of their
enemies, whereas they might easily survive them and triumph over their
destruction. In opposition to this French gallantry, which often
involves the murderer in a death more cruel than that he has given, he
pointed to the Florentine traitor with his amiable smile and his deadly
poison. He indicated certain powders and potions, some of them of dull
action, wearing out the victim so slowly that he dies after long
suffering; others violent and so quick, that they kill like a flash of
lightning, leaving not even time for a single cry. Little by little
Sainte-Croix became interested in the ghastly science that puts the lives
of all men in the hand of one. He joined in Exili's experiments; then he
grew clever enough to make them for himself; and when, at the year's end,
he left the Bastille, the pupil was almost as accomplished as his master.

Sainte-Croix returned into that society which had banished him, fortified
by a fatal secret by whose aid he could repay all the evil he had
received. Soon afterwards Exili was set free--how it happened is not
known--and sought out Sainte-Croix, who let him a room in the name of his
steward, Martin de Breuille, a room situated in the blind, alley off the
Place Maubert, owned by a woman called Brunet.

It is not known whether Sainte-Croix had an opportunity of seeing the
Marquise de Brinvilliers during his sojourn in the Bastille, but it is
certain that as soon as he was a free man the lovers were more attached
than ever. They had learned by experience, however, of what they had to
fear; so they resolved that they would at once make trial of
Sainte-Croix's newly acquired knowledge, and M. d'Aubray was selected by