Plant anatomy
It was in the late 1600s that plant anatomy became refined into a modern science. Italian doctor and microscopist, Marcello Malpighi, was one of the two founders of plant anatomy. In 1671 he published his "Anatomia Plantarum", the first major advance in plant physiogamy since Aristotle. The other founder was the British doctor Nehemiah Grew. He published "An Idea of a Philosophical History of Plants" in 1672 and "The Anatomy of Plants" in 1682. Grew is credited with the recognition of plant cells, although he called them 'vesicles' and 'bladders'. He correctly identified and described the sexual organs of plants (flowers) and their parts.
Guillaume de Baillou
Guillaume de Baillou is considered to be the first epidemiologist since Hippocrates, and is credited as the founder of modern epidemiology. He did extensive studies of epidemics that plagued Paris, and is additionally credited with providing the first clinical description of pertussis (whooping cough) in 1578. He also provided the first modern descriptions of rheumatism and arthritis, of which he defined in the treatise "Liber de Rheumatismo et Pleuritide dorsali".