For a Night of Love by Émile Zola

When very small, Therese de Marsanne made Colombel her fag and butt. He was her elder by about six months, and Francoise, his mother, had weaned him in order to nurse Therese.

Therese was a terrible child. Not that she was a noisy tomboy. On the contrary, she had a singular seriousness that made her appear as a well bred child before visitors, for whom she made graceful curtseys. But she had very strange ways; she would burst into inarticulate cries, stamping madly about, when she was alone.