Answer:
"My mother and I were separated when I was but an infant-before I knew her as my mother. "
Step-by-step explanation:
In the text shown above, it is possible to see that Douglass argues that slave children are separated from their mothers at the very beginning of their lives. The evidence he shows for this argument is that he experienced this separation when he was a child, as he was taken away from his mother at a very young age.
We can see that this is the evidence, because an evidence is a proof and justification that an argument is true and real. When Douglass claims that the slave family is separated, he justifies this claim by showing that he went through this separation and lived this experience, so he can confirm that the claim is true.