Dickens knew that a flint-hearted man like Scrooge could not be changed by forces brought to bear from without.

cold, cold-blooded, cold-hearted; black-hearted, hard-hearted, flint-hearted, marble-hearted, stony-hearted; hard of heart, unnatural; ruthless &c (unmerciful) 914.1; relentless &c (revengeful)

On the one side here is a silly, flint-hearted, evil-minded, sulky old woman, necessary to no oneon the contrary, pernicious to alland who does not know herself why she lives.