recesses of heart

This once accomplished, that mysterious monitor within us commonly known as "Conscience" grows until it attains an excessive sensitiveness which penetrates the minutest acts of life and the deepest recesses of heart and mind.

Now and then, when alone in his shabby bedroom, reading a dull book, or duly preparing to retire, far in the dim recesses of heart and brain a faint pain became apparent—if it could still be called pain, this vague ghost of anger stirring in the ashes of dead years—and at such moments he thought of Graylock, and of another; and the partly paralyzed emotion, which memory of these two evoked, stirred him finally to think of Cecile.