The Wealth of Nations by Part 4 Chapter 7 Page 97

to free servants, but which never can belong to a slave who is treated as slaves commonly are in countries where the master is perfectly free and secure.

That the condition of a slave is better under an arbitrary than under a free government is, I believe, supported by the history of all ages and nations. In the Roman history, the first time we read of the magistrate interposing to protect the slave from the violence of his master is under the emperors. When Vedius Pollio, in the presence of Augustus, ordered one of his slaves, who had committed a slight fault, to be cut into pieces and thrown into his fish pond in order to feed his fishes, the emperor commanded him, with indignation, to emancipate immediately, not only that slave, but all the others that belonged to him.