Definition of Metaphor
In Chapter 10, Douglass describes how enslavers purposely make holidays unpleasant so that enslaved people will not want them. He calls the institution of slavery "fraud," which 19th-century white readers would have taken as a metaphor:
I have said that this mode of treatment is a part of the whole system of fraud and inhumanity of slavery. It is so. The mode here adopted to disgust the slave with freedom, by allowing him to see only the abuse of it, is carried out in other things. For instance, a slave loves molasses; he steals some. His master, in many cases, goes off to town, and buys a large quantity; he returns, takes his whip, and commands the slave to eat the molasses, until the poor fellow is made sick at the very mention of it.
In Chapter 11, Douglass critiques the way abolitionists operating the underground railroad proclaim themselves publicly. Douglass uses an implicit metaphor to claim that a more useful and indeed fairer system would be to keep everything as secret as possible:
Unlock with LitCharts A+I would keep the merciless slaveholder profoundly ignorant of the means of flight adopted by the slave. I would leave him to imagine himself surrounded by myriads of invisible tormentors, ever ready to snatch from his infernal grasp his trembling prey. Let him be left to feel his way in the dark; let darkness commensurate with his crime hover over him; and let him feel that at every step he takes, in pursuit of the flying bondman, he is running the frightful risk of having his hot brains dashed out by an invisible agency.