#5 Germ Theory
Before the development of the ‘germ theory’, it was a common belief of the medical practitioners that diseases were caused by spontaneous generation – a theory that revolved around the idea that diseases could occur from non-living matter.
The germ theory that proposed that diseases were caused by micro-organism was developed sometime in the 16th century and was later solidified by the demonstrations performed by Louis Pasteur in 1861.
Sir Joseph Lister, a British surgeon who pioneered the process of sterilization and antiseptic surgery, actually made practical use of the knowledge gathered by his predecessors and colleagues. He popularised the method of sterilizing surgical instruments and operation rooms, which is a standard norm today.