How the problem of infection was overcome
1. Until germ theory in the 1850s, surgeons didn't take precautions to protect open wounds
2. Joseph Lister and the discovery of antiseptics
3. Lister heard that carbolic spray was used on sewage, he knew sewage had a similar smell to gangrene
4. He had read the work of Pasteur on his germ theory
5. He was prepared to take risks