There are so many instances of mental and physical abuse at the hands of slave owners in Douglass' book. Frederick was separated from his mother when he was born, but she sometimes walked 12 miles at night from the plantation where she worked in order to see him. One can only imagine what lengths a mother would go to in order to see her son that was taken from her, and the mental anguish this would cause.
Douglass' aunt is also beat by the overseer, cruelly whipped for a minor transgression. Any time a slave "stole" food or made a comment against the owners, they were whipped and beaten. Slaves are even murdered, and no one is punished for these murders because slave's lives are not seen to have as much value.
Even if the slaves aren't beaten, they never have warm enough clothes or enough food. They live in poor conditions and do not have adequate shelter.
At one point, Douglass lives with Sophia Auld, who is kind to him and allows him some more freedoms than he is used to. However even under these circumstances life is not wonderful. Douglass secretly learns how to read, realizing that literacy is the key to knowledge and freedom.
When his master dies, the slaves are all sold and split up. Douglass' grandmother is old and left to die in the woods, leaving Douglass more disheartened and more determined to escape slavery. The plantation where Douglass ends up is terrible and the slaves never have enough to eat. He is eventually sent to work with a man who is well known for his cruelty. This man is Mr. Covey, and he takes delight in tricking his slaves and catching them at "transgressions" which he then punishes them for. Douglass' time with this man is horrific. He is beaten, he falls ill, and he witnesses terrible injustices. But it also empowers him, because he begins to fight back, and ultimately runs to his freedom.
Douglass' depiction of the life of the slave is filled with examples of emotional and physical cruelty. The events in chapter 4, for example, that show the complete disregard for the life of the slave is fairly powerful evidence of the physical torment suffered. The negation of human rights is evident, to the point that even life, itself, is taken from the slave. In chapter 3, the description of the fruit that hangs in the slaveowner's garden and the strict punishment that follows if a slave breaks the rules help to enforce the mentally cruel aspect of slavery. Any institution that separates families, forces children into a life for bondage, and helps to wither the soul and spirit of a group of people can exact cruelty and torment on as many levels as possible.