The movement of the passion in Othello is exceedingly different from that of Macbeth.  In Macbeth there is a violent struggle between opposite feelings, between ambition and the stings of conscience, almost from first to last:  in Othello, the doubtful conflict between contrary passions, though dreadful, continues only for a short time, and the chief interest is excited by the alternate ascendancy of different passions, the entire and unforeseen change from the fondest love and most unbounded confidence to the tortures of jealousy and the madness of hatred.  The revenge of Othello, after it has once taken thorough possession of his mind, never quits it, but grows stronger and stronger at every moment of its delay.  The nature of the Moor is noble, confiding, tender, and generous; but his blood is of the most inflammable kind; and being once roused by a sense of his wrongs, he is stopped by no considerations of remorse or pity till he has given a loose to all the dictates of his rage and his despair.  It is in working his noble nature up to this extremity through rapid but gradual transitions, in raising passion to its height from the smallest beginnings and in spite of all obstacles, in painting the expiring conflict between love and hatred, tenderness and resentment, jealousy and remorse, in unfolding the strength and the weaknesses of our nature, in uniting sublimity of thought with the anguish of the keenest woe, in putting in motion the various impulses that agitate this our mortal being, and at last blending them in that noble tide of deep and sustained passion, impetuous but majestic, that ’flows on to the Propontic, and knows no ebb’, that Shakespeare has shown the mastery of his genius and of his power over the human heart.  The third act of Othello is his masterpiece, not of knowledge or passion separately, but of the two combined, of the knowledge of character with the expression of passion, of consummate art in the keeping up of appearances with the profound workings of nature, and the convulsive movements of uncontrollable agony, of the power of inflicting torture and of suffering it.  Not only is the tumult of passion heaved up from the very bottom of the soul, but every the slightest undulation of feeling is seen on the surface, as it arises from the impulses of imagination or the different probabilities maliciously suggested by Iago.  The progressive preparation for the catastrophe is wonderfully managed from the Moor’s first gallant recital of the story of his love, of ‘the spells and witchcraft he had used’, from his unlooked-for and romantic success, the fond satisfaction with which he dotes on his own happiness, the unreserved tenderness of Desdemona and her innocent importunities in favour of Cassio, irritating the suspicions instilled into her husband’s mind by the perfidy of lago, and rankling there to poison, till he loses all command of himself, and his rage can only be appeased by blood.  She is introduced, just before lago begins to put his scheme in practice, pleading for Cassio with all the thoughtless gaiety of friendship and winning confidence in the love of Othello.