However as Saccard was returning to the Rue de Penthièvre some little while afterwards, he fancied he saw Madame Sidonie's black dress leave his brother's abode and glide rapidly along the houses. He hastened forward, but lost all trace of the black garment. The woman of business had one of those spare figures which so easily lose themselves in a crowd. This set him thinking, and it was from this moment that he commenced to study his sister more attentively. It was not long before he began to understand the immense task performed by that pale and shadowy little body, whose entire face seemed to squint and melt away. He came to look upon her with respect. She had the true Rougon blood in her veins. He recognised that appetite for money, that longing for every kind of intrigue which was characteristic of the family; only, in her case, thanks to the surroundings amidst which she had grown old, thanks to that Paris where every morning she had been obliged to set forth to seek her evening meal, the common temperament had deviated from its usual course to produce this extraordinary hermaphrodism of a woman changed into a being without a gender, both man of business and procuress at the same time. When Saccard, after having fixed upon his plan, was seeking for the means for putting it into execution, he naturally bethought him of his sister. She shook her head, and with a sigh alluded to the three milliards. But the civil servant would not humour her whim, he pulled her up rather roughly each time she mentioned the debt connected with the Stuarts; such a chimera seemed to him to dishonour so practical an intelligence. Madame Sidonie, who quietly swallowed the most cutting irony without in any way allowing her convictions to be shaken, next explained to him in a very lucid manner that he would never raise a sou, having no security to offer. This conversation took place opposite the Bourse, where she no doubt dabbled with her savings. Towards three o'clock one was sure to find her leaning against the railing to the left, near the post-office; it was there that she gave audience to individuals as fishy and shadowy as herself. Her brother was on the point of leaving her, when she murmured regretfully: "Ah! if only you were not married!" This reticence, the full and exact sense of which he was unwilling to ask, made Saccard singularly thoughtful.