Even on the estates of moderate size which were not entirely pastoral, slave-labour was the rule. We know something of such a farm from the treatise on agriculture written by Cato at this time, which has come down to us entire; and it is plain from what he says that though free labour might be employed at certain seasons, _e.g._ at harvest, the economic basis of the business was slave-labour. There is no doubt that all over Italy the small farm and the free cultivator were fast disappearing, with the rapid growth of capital and the cheapness of slaves. In the city of Rome, now beginning to harbour a vast population of many races, the number of domestic slaves tended constantly to increase; they were employed in every capacity by men of wealth and business. Many of them were cultivated men, Greeks for example, who could act as clerks, secretaries or teachers, and these had a fair chance of earning their freedom in time; but great numbers were low and vicious beings, who had no moral standard but that of obedience to a master, no moral sanction except punishment. Thus, though the shrinkage of the free population was evil enough, the remedy for it was even worse. The slave, plucked up by the roots from the soil in which he had flourished in his native land, deprived of family, property, religion, must in the majority of cases become a demoralised and hopeless being. In the plays of Plautus, which date from this period, the slave is a liar and a thief, and apparently without a conscience. For the slave-owner, too, the moral results were bad enough, though not so obvious at first sight. A man who is served by scores of fellow-creatures who are absolutely at his mercy is liable to have his sense of duty gradually paralysed. Towards them he has no obligations, only rights; and thus his sense of duty towards his free fellow-citizens is apt to be paralysed too. A habit of mind acquired in dealing with one set of men naturally extends itself and affects all human relations. And so the Roman character, naturally hard enough, came in the later days of the Republic to be harder than ever. In our next two chapters we shall meet with unmistakable proofs of this. Incredible cruelty, recklessness of human life, callousness in dealing with the vanquished and the subject peoples, meet us at every turn in that dark age of Mediterranean history. Under the baleful influence of slavery the hard Roman nature had become brutalised; and we have to wait for the Christian era before we find any sign of sympathy with that vast mass of suffering humanity with which the Roman dominion was populated.