"Is your wife going the same way as her mother and all knowing it?"

In Victorian times, madness was widely believed to be hereditary, and females were seen to be more predisposed towards madness than men –  a mother would pass her madness on to her daughter.

In Jane Eyre, a genetic predisposition towards madness is the only explanation given for Bertha's insanity. See 'Madness Within Victorian Society' for more information.