what dramatic function does othellos fit serve

Othello's fit serves to illuminate the audience of his descent into savagery; ironically, he becomes the passion-stirred, wicked beast that others had erroneously accused him of being because of his race. Iago notes that Othello "breaks out into savage madness" in this fit; indeed, the primal seems to be taking over the more civilized aspects of Othello (IV.i.55). Othello refers to himself as a "horned man," ashamed of this descent; yet it has settled upon him, and he will struggle in vain to regain his dignity (IV.i.62).