and kill the boar, ordered him to be instantly crucified, under the barbarous pretext that the law prohibited the use of this weapon, as of all others, to slaves." The natural consequence of this cruel treatment was unbounded hatred of the master by the slave. "We have as many enemies," says Seneca, "as we have slaves." And what rendered the situation perilous was the numerical superiority of the slave over the free population. "They multiply at an immense rate," says Tacitus, "whilst freemen diminish in equal proportion." Pliny the Younger gave expression to the universal apprehension when he wrote: "By what dangers we are beset! No one is safe; not even the most indulgent, gentlest master." Precautionary measures were adopted from time to time both by individuals and by the government to prevent concerted action among the slaves and to conceal from them all evidences of their own strength. To keep down mutiny among his slaves, Cato is said to have constantly excited dissension and enmity among them. "It was once proposed," says Gibbon, "to discriminate the slaves by a peculiar habit; but it was justly apprehended that there might be some danger in acquainting them with their own numbers."[169] If the Roman masters maltreated and destroyed the bodies of their slaves, the slaves retaliated by corrupting and destroying the morals of their masters. The institution of slavery was one of the most potent agencies in the demoralization of ancient Roman manners. The education of children was generally confided to the slaves, who did not fail to poison their minds and hearts in many ways. In debauching their female slaves, the Roman masters polluted their own morals and corrupted their own manhood. The result teaches us that the law of physics is the law of morals: that action and reaction are equal, but in opposite directions.