This chapter provides a detailed assessment of Walter Bailey’s medical genres in the vernacular and how they reflect changing thought styles from scholasticism to empiricism. The ongoing process is demonstrated by first-hand evidence obtained by analysing both macrolevel structural compositions of genres and various text types within them. Language change is located on the discourse level by identifying stylistic varieties, showing the mechanism of change on the ideological level. Bailey belonged to the learned elite of his time and mastered a large repertoire of different genres and text types. He gives us convincing proof of the early transition period by employing old and creating new ways of writing. He developed the genre script of the scholastic commentary to unprecedented perfection in Peppers (1588), and innovated a new style of reporting on his experiments in Waters a year earlier. The passage anticipates the future way of doing and writing science, showing the author’s curiosity and inquisitiveness, qualities that are typically attributed to seventeenth-century Royal Society scientists. The new mode of knowing surfaces passim in his other texts too, where observation of nature is preferred to book wisdom.