With the rejection of Galen’s humoural theory, combined with scientific advancements, such as the microscope, progress in medicine and anatomy moved at a pace. Greater emphasis was now being placed on the causes of disease. New chemical tests were beginning to develop, and surgery was becoming safer due to the advancement of anaesthetics. Despite this significant progression, the cause of disease was still often attributed to magic, or ‘miasma theory’, where poisonous vapours in the air were thought to seep from rotting matter, causing disease. This theory was based on the observation that disease outbreaks often occurred in areas with poor sanitation and foul odours.