The titles which divines and canonists have considered to be good and valid for the possession of slaves, are purchase, inheritance, gift, birth, slaves made in war, and sentenced for crime; but, in all cases, the title is vitiated when not sustained by the civil law. Yet the civil law may be repealed, or ameliorated, so that prisoners taken in war or crime may not be subject to death or servitude, in which case the validity of the title follows in the footsteps of the civil law; but these conditions primarily exist, as perpetual as the condition of man. The civil law, by its intervention, merely diverts the action during its rule. But, in all cases of a secondary title, the validity follows the character of the previous holding, as no man can sell, give, or leave by inheritance a better title than that which he has. The question thus runs to the origin of what gives a good title, to wit, the condition that enforces one to be sold, or to sell himself, a slave, in favour of life. True, Blackstone, Montesquieu, and others of less note, contend that no man has a right _to sacrifice his liberty_; and what is their argument? They make an assumption, where there is no parallel, “that liberty is of equal worth to life;” but before their argument is good, they must show that liberty is of more value than life: for surely a man may barter an equal for an equal. They cry, “God gave all men liberty.” Even that is a fiction. The truth is, God gave no man liberty, only upon conditions. But to show that life is of more value than liberty, we need only observe that even with the loss of liberty there is hope—hope of change, of liberty, and of the means of sustaining it; and such hopes have often been realized. There is no truth in the proposition that liberty is of equal value (or rather superior) to life. The doctrine therefore is, that man, in his natural state, is the master of his own liberty, and may dispose of it as he sees proper in favour of life; that he may be deprived of it by force, in consequence of crime, or from his not being able to sustain it; and in all cases where liberty has become of less value than life, and both cannot be sustained, the one may be properly exchanged for the safety of the other. And upon this principle, in those countries where the parent had the right, by their law, to put to death his own children, he also had the right to sell them into slavery; and further, by natural law, where the parent cannot sustain the life of his child, where civil law gives him no power over its life, he yet, in favour of life, may sell him into slavery. Natural law recognises the principle that the child, of right, is subject to the condition of the parent; and in these enfeebled conditions of man, for sake of more certainty, the civil law usually acknowledges the maternal line. It acknowledges the paternal line only when the elevated condition forms a presumption of equal certainty.