Chapter 7 - Narrative of the Life of Frederick Douglass

… ]I was compelled to resort to various stratagems. I had no regular
teacher. My mistress, who had kindly commenced to instruct me, had, in
compliance with the advice and direction of her husband, not only ceased to
instruct, but had set her face against my being instructed by any one else.
It is due, however, to my mistress to say of her, that she did not adopt
this course of treatment immediately. She at first lacked the depravity
indispensable to shutting me up in mental darkness. It was at least
necessary for her to have some training in the exercise of irresponsible
power, to make her equal to the task of treating me as though I were a
brute.