In the early decades of the nineteenth century, French physicians began using the microscope more and more. The physician Pierre Rayer performed microscopic and chemical analyses of urine for the first time in history. The physiologist and pharmacologist François Magendie began using the instrument as a teaching tool in his physiology classes, and the physicians Gabriel Andral and Jules Gavarret started to analyze blood under the lens. By the time Lister was entering medical school, some Parisian physicians were even using microscopes
