Therese, a fortnight or three weeks before, had drawn from the bank the few thousand francs that remained of her marriage portion, and kept them locked up in a drawer--a circumstance that had not escaped Laurent.

The fate of Madame Raquin did not trouble them an instant.
A few weeks previously, Laurent had met one of his old college friends, now acting as dispenser to a famous chemist, who gave considerable attention to toxicology.

This friend had shown him over the laboratory where he worked, pointing out to him the apparatus and the drugs.
One night, after he had made up his mind in regard to the murder, and as Therese was drinking a glass of sugar and water before him, Laurent remembered that he had seen in this laboratory a small stoneware flagon, containing prussic acid, and that the young dispenser had spoken to him of the terrible effects of this poison, which strikes the victim down with sudden death, leaving but few traces behind.

And Laurent said to himself, that this was the poison he required.

On the morrow, succeeding in escaping the vigilance of Therese, he paid his friend a visit, and while he had his back turned, stole the small stoneware flagon.
The same day, Therese took advantage of the absence of Laurent, to send the large kitchen knife, with which they were in the habit of breaking the loaf sugar, and which was very much notched, to be sharpened.