Thus far common human experience and its dictates. As a responsible man and the head of his family, the debtor, at least among the Semites, had power over the labour of the other members of his family. There may be peoples where this power does not exist, if so, the power may be called a Semitic trait. But in both the Code of Hammurabi and the Book of the Covenant we have some reason to suppose the debtor would have power to offer not only his own labour but that of his wife, often the better worker of the two, or that of a son or daughter, or of a slave, as well as or instead of his own. Exactly how far his power over the members of his own household extended may be set down, if we chose, as depending upon Semitic custom, if we can show that this extent of power is common to all Semites, at any rate in early times, and is not shared with non-Semitic folk. The parallels in Roman law do show that it did not remain exclusively Semitic, unless it be held that the Twelve Tables were so influenced by Eastern civilization as to have derived this feature ultimately from a Semitic source. It was probably Sumerian also, but there we may perhaps derive it from an early Semitic source. At any rate we do find it common to both Babylonia and Israel, whether they derived it from a common source or obtained it independently. Now how long shall the debtor or his hostage serve the creditor to pay off the debt? The creditor might well say in the case of a slave, who in practice was often taken as an antichretic pledge for a loan, his labour being supposed to pay the interest on the loan without affecting the capital, that he had a right to keep him always. Theoretically this was true if the loan was about the value of the slave. It would practically be accepting the slave as a payment of the loan. The value of a slave was often very little in excess of the cost of keeping him, feeding, clothing, and housing him. Indeed, he was even an anxiety after he became adult. The owner usually did wisely in providing him with a slave-girl for wife and so breeding a family of slaves, who after they had been kept to adult age might be sold profitably. But even this was a speculation, and at the best not a very profitable business. The creditor who accepted the debtors slave as a hostage for debt usually took the opportunity of a sale to pass him on. A slave-girl had other uses than her work and was usually more saleable. Hence she was more likely to be accepted and offered as a hostage. The Code of Hammurabi here steps in with a remarkable set of restrictions upon the freedom of action of the debtor and creditor. The debtor cannot complain if the creditor sells the slave given him as hostage. But if it is a slave-girl who has borne children to the debtor, she cannot be sold. She may be pledged or given to work off a debt, but not alienated by the creditor (§ 118).