This presentation is based on Edexcel GCSE History of Medicine. Each unit has many pictures and diagrams to make the lesson more accessible to all ability pupils. This unit is about the work of Louis Pasteur, his Germs Theory, as well as brief notes on works of Joseph Lister, and John Tyndall, and role of dr Henry Bastian in spreading their discoveries in Britain. There are links to two videos one about Louis Pasteur and second one about Joseph Lister.