The owner could sell a slave to an individual or a society, who wanted to emancipate him. Slaves frequently bought themselves. A free negro sometimes bought husband or wife and children, and then petitioned the state to free them. All bills of the sale of slaves had to be in writing and attested by at least one creditable witness. If the bill of sale was contested, two witnesses were required.[13] Philanthropic individuals and societies could have emancipated a great many slaves, if the state had not made its consent a necessary part of such manumission. When one considers how the benevolence of slave owners or the generosity of societies might have flooded a community with stupid, ignorant, and vicious negroes, he can easily see why society asserted the right to regulate the ownership of this kind of property. (5) _By Implication._ If the master by his acts or treatment of a slave, or in conversation with another, indicated that he meant to give a slave his freedom, the courts would recognize this as a basis for a suit for freedom.[14] The institution of a suit against a slave was an implication of his freedom, otherwise the bequest had no effect.[15] (6) _By the Effect of Foreign Laws._ If a slave owner of Tennessee moved to a free state with his slaves to reside permanently, this would indicate his intention to free them. If on entering such a state with his slaves, he agreed to free them at a certain future date, this would give the slaves a cause for a suit of freedom if he should later decide to return to Tennessee before the expiration of the time set for their emancipation.[16] Of course, Tennessee laws permitted a free negro to adopt a master and convey himself into slavery, but this was voluntary on his part.[17] B. THE EXTENT OF EMANCIPATION IN TENNESSEE.