But I undertake to affirm that no usage, professional or social, can give any apology for joining the pack of the Slave-Hunter. Mr. Dunning, one of the persons in this predicament, showed that he acted against his better nature.[156] The first words in his argument were: "It is incumbent on me to justify the detainer of the negro." Pray, why incumbent on him? He was then careful to show that he did not maintain any absolute property in him; and he proceeded to say, among other things, that it was his misfortune to address an audience, the greater part of which, he feared, was prejudiced the other way,--that, for himself, he would not be understood to intimate a wish in favor of Slavery, but that he was bound in duty to maintain those arguments most useful to the claimant, so far as consistent with the truth; and he concluded with this conscience-stricken appeal: "I hope, therefore, I shall not suffer in the opinion of those whose honest passions are fired at the name of Slavery; I hope I have not transgressed my duty to Humanity."[157] Clearly the lawyer had transgressed his duty to Humanity. No man can rightfully enforce a principle which violates human nature; nor can any subtilty of dialectics, any extent of erudition, or any grandeur of intellect sustain him. Notwithstanding the character for liberal principles which John Dunning acquired, and which breathes in his sensitive excuses,--notwithstanding his double fame at once in Westminster Hall and Saint Stephen's Chapel,--notwithstanding the peerage which he won,--this odious service rendered to a Slave-Hunter, calling himself a Virginia gentleman, cries in judgment against him, and will continue to cry, as time advances. (Do not start, Mr. President,--I am narrating occurrences in another hemisphere and another century.) As well undertake a Slave-Hunt in the deserts of Africa as in the streets of London. As well pursue the fugitive with the hired whip of the overseer as with the hired argument of the lawyer. As well chase him with the baying of the blood-hound as with the tongue of the advocate. It is the lawyer's clear duty to uphold _human rights_, whether in the loftiest or the lowliest; and when he undertakes to uphold a wrong outrageous as Slavery, his proper function is so far reversed that he can be aptly described only in the phrase of the Roman Church, _Advocatus Diaboli_, the Devil's Advocate.