of the Irish Confederates caught the flame, and that revolution, and revolution alone, became the goal of their endeavours.  When Mitchel withdrew from the Confederation in March, 1848, the principles of constitutional action were still in the ascendancy; when he rejoined it a month later, the cry “to the registries,” was superseded by fiery appeals summoning the people to arms.  In the first week of April, the doctrine which John Mitchel had long been propounding, found expression in the leading columns of the Nation:—­“Ireland’s necessity,” said Duffy, “demands the desperate remedy of revolution.”  A few weeks later, the same declaration was made in the very citadel of the enemy’s power.  It was O’Brien who spoke, and his audience was the British House of Commons.  With Messrs. Meagher and Hollywood, he had visited Paris to present an address of congratulation on behalf of the Irish people to the Republican government; and on taking his seat in the House of Commons after his return, he found himself charged by the Ministers of the Crown, with having gone to solicit armed intervention from France on behalf of the disaffected people of Ireland.  O’Brien replied in a speech such as never was heard before or since within the walls of the House of Commons.  In the midst of indescribable excitement and consternation, he proceeded to declare in calm deliberative accents—­“that if he was to be arraigned as a criminal, he would gladly endure the most ignominious death that could be inflicted on him rather than witness the sufferings and indignities he had seen inflicted by the British legislature on his countrymen.  If it is treason,” he exclaimed, “to profess disloyalty to this House and to the government of Ireland, by the parliament of Great Britain—­if that be treason, I avow it.  Nay, more, I say it shall be the study of my life to overthrow the dominion of this Parliament over Ireland.”  The yells and shouts with which these announcements were received shook the building in which he stood, and obliged him to remain silent for several moments after the delivery of each sentence; but when the uproar began to subside, the ringing tones of O’Brien rose again upon the air, and with the stoicism of a martyr, and the imperturable courage of a hero, he proceeded.  “Irish Freedom,” he said, “must be won by Irish courage.  Every statesman in the civilized globe looks upon Ireland as you look upon Poland, and upon your connection as entirely analogous to that of Russia with Poland.  I am here to-night to tell you, that if you refuse our claims to legislative independence, you will have to encounter during the present year, the chance of a Republic in Ireland.”