But the most remarkable part of the Aztec code was that relating to slavery. There were several descriptions of slaves: prisoners taken in war, who were almost always reserved for the dreadful doom of sacrifice; criminals, public debtors, persons who, from extreme poverty, voluntarily resigned their freedom, and children who were sold by their own parents. In the last instance, usually occasioned also by poverty, it was common for the parents, with the master’s consent, to substitute others of their children successively, as they grew up; thus distributing the burden as equally as possible among the different members of the family. The willingness of freemen to incur the penalties of this condition is explained by the mild form in which it existed. The contract of sale was executed in the presence of at least four witnesses. The services to be exacted were limited with great precision. The slave was allowed to have his own family, to hold property, and even other slaves. His children were free. No one could be born to slavery in Mexico;[67] an honorable distinction, not known, I believe, in any civilized community where slavery has been sanctioned.[68] Slaves were not sold by their masters, unless when these were driven to it by poverty. They were often liberated by them at their death, and sometimes, as there was no natural repugnance founded on difference of blood and race, were married to them. Yet a refractory or vicious slave might be led into the market, with a collar round his neck,[69] which intimated his bad character, and there be publicly sold, and, on a second sale, reserved for sacrifice.[70] Such are some of the most striking features of the Aztec code, to which the Tezcucan bore great resemblance.[71] With some exceptions, it is stamped with the severity, the ferocity indeed, of a rude people, hardened by familiarity with scenes of blood, and relying on physical instead of moral means for the correction of evil.[72] Still, it evinces a profound respect for the great principles of morality, and as clear a perception of these principles as is to be found in the most cultivated nations.