If we go back to the ancient Greeks, we find an interesting distinction. A slave was not believed on oath; so that one is recorded as exclaiming, in words which might be adopted in our day: “I know I am a slave: I don’t know even what I do know.”[81] But, though not believed on oath, his evidence was always taken with torture. On this account his testimony appears to have been considered of more value even than that of a freeman. Isæus, in arguing a case, said: “When slaves and freemen are at hand, you do not make use of the testimony of freemen; but, putting slaves to the torture, you thus endeavor to find out the truth of what has been done.” Any person might offer his own slave to be examined by torture, or demand the same thing of his adversary, and the refusal of the latter was regarded as a strong presumption against him.[82] Thus cruelly did this sharp people seek to counteract the senseless rule of exclusion. Torture was recognized, but justice was not absolutely sacrificed. The Romans seem to have borrowed the practice from the Greeks, or they were inspired to kindred cruelty. Not only slaves, but even free persons of an inferior condition, were seldom examined except under torture. Any person who wished the testimony of a slave might obtain it on giving sufficient security to the master for full reparation on account of damage from his torture. Mr. Jefferson states mildly our own practice, in contrast with that of Rome, when he says: “With the Romans, the regular method of taking the evidence of their slaves was under torture; here it has been thought better never to resort to their evidence.”[83] In the latter days of the Empire, a general rule made the slave inadmissible as witness for or against his master or his master’s children, except in cases of treason, where the danger of the crime overruled ordinary considerations, and also in cases of incest and adultery, for the good reason that _in a society where all domestics were slaves any other evidence could hardly be procured_.[84] But the latter reason might obviously exist in the case of any crime; so that, on principle, when other proofs were wanting, resort might be had to the testimony of slaves. Indeed, a learned commentator on the Roman Law has distinctly said that this law did not admit slaves to be witnesses, unless the cause was difficult, looking to the welfare of the republic, _or other proofs were wanting_: “_Servos lex civilis non patitur testes esse, … nisi causa sit ardua, ad rei publicæ spectans utilitatem, aut aliæ desint probationes._”[85] It became customary, in civil matters, to admit the testimony of slaves as to their own acts, although affecting the interests of their masters; and after the establishment of Christianity, when heresy took its place as a crime to be dreaded as much as treason, the testimony of slaves was received equally with regard to each.