Drapetomania

Drapetomania

He stated that the malady was a consequence of masters who "made themselves too familiar with [slaves], treating them as equals."
"If any one or more of them, at any time, are inclined to raise their heads to a level with their master or overseer, humanity and their own good requires that they should be punished until they fall into that submissive state which was intended for them to occupy. They have only to be kept in that state, and treated like children to prevent and cure them from running away."

http://en.wikipedia.org/wiki/Drapetomania