Iago.  Call up her father: 
     Rouse him [Othello], make after him, poison his delight,
     Proclaim him in the streets, incense her kinsmen,
     And tho’ he in a fertile climate dwell,
     Plague him with flies:  Tho’ that his joy be joy,
     Yet throw such changes of vexation on it,
     As it may lose some colour.

In the next passage, his imagination runs riot in the mischief he is plotting, and breaks out into the wildness and impetuosity of real enthusiasm.

   Roderigo.  Here is her father’s house:  I’ll call aloud.

   Iago.  Do, with like timorous accent and dire yell,
     As when, by night and negligence, the fire
     Is spied in populous cities.

One of his most favourite topics, on which he is rich indeed, and in descanting on which his spleen serves him for a Muse, is the disproportionate match between Desdemona and the Moor.  This is a clue to the character of the lady which he is by no means ready to part with.  It is brought forward in the first scene, and he recurs to it, when in answer to his insinuations against Desdemona, Roderigo says: 

     I cannot believe that in her—­she’s full of most blest
     conditions.

   Iago.  Bless’d fig’s end.  The wine she drinks is made of
     grapes.  If she had been blest, she would never have married
     the Moor.

And again with still more spirit and fatal effect afterwards, when he turns this very suggestion arising in Othello’s own breast to her prejudice.

   Othello.  And yet how nature erring from itself—­

   Iago.  Aye, there’s the point;—­as to be bold with you,
     Not to affect many proposed matches
     Of her own clime, complexion, and degree, &c.

This is probing to the quick.  Iago here turns the character of poor Desdemona, as it were, inside out.  It is certain that nothing but the genius of Shakespeare could have preserved the entire interest and delicacy of the part, and have even drawn an additional elegance and dignity from the peculiar circumstances in which she is placed.  The habitual licentiousness of Iago’s conversation is not to be traced to the pleasure he takes in gross or lascivious images, but to his desire of finding out the worst side of everything, and of proving himself an over-match for appearances.  He has none of ’the milk of human kindness’ in his composition.  His imagination rejects everything that has not a strong infusion of the most unpalatable ingredients; his mind digests only poisons.  Virtue or goodness or whatever has the least ‘relish of salvation in it’ is, to his depraved appetite, sickly and insipid:  and he even resents the good opinion entertained of his own integrity, as if it were an affront cast on the masculine sense and spirit of his character.  Thus at the meeting between Othello and Desdemona, he exclaims, ’Oh, you are well tuned now:  but I’ll set down the pegs that make this music, as honest as I am—­his character of bonhommie not sitting at all easily upon him.  In the scenes where he tries to work Othello to his purpose, he is proportionably guarded, insidious, dark, and deliberate.  We believe nothing ever came up to the profound dissimulation and dexterous artifice of the well-known dialogue in the third act, where he first enters upon the execution of his design.