The correspondence between "style" and "temperament" plays an important role in the rhetorics of the Renaissance. The purpose of this paper is to analyze the temperamental determinations marking polemical enunciation by confronting medical and rhetorical theories. From the sixteenth century onwards, the "sanguine" ideal of Ciceronian style gives way to the rival temperament of the melancholy, characterized by genius but also prone to pathological and stylistic fury if yellow bile gets in the way. Polemists consider humoral inspiration either as an enslaving to physical diseases or as a freely consented physiological engagement, thus restating the fundamental question of stylistic free will. The dispute between Garasse, Ogier and Guez de Balzac around 1620 testifies to the fact that classical esthetics switch from the tragic grandeur of poetic "furor" to more reasoned poetics that demystify the temperamental Muse.