dog-hearted

“She and Regan are dog-hearted: they are tigers, not daughters: each is an adder to the other: the flesh of each is covered with the fell of a beast.”

Shakespearean Tragedy Lectures on Hamlet, Othello, King Lear, Macbeth

“To his own lips '-- when his' dog-hearted daughters 'have returned to his own bosom the cruel edge of that _unnatural_ wrong which he has impiously dared to summon nature herself -- violated nature -- to witness, this is the greeting which the _unnatural_ Goneril receives, on her return to her husband, when she complains to him of her welcome --”

The Philosophy of the Plays of Shakspere Unfolded