Victorian surgeons wore coats stiff with dried blood as a badge of experience and spoke proudly of the good old surgical stink, while patients often died from infection after even simple operations. This episode follows Joseph Lister, a Quaker whose father improved the microscope, through a nervous breakdown, his early success saving a stabbing victim named Julia Sullivan, and his realization that wound decay was being triggered from outside the body, not by miasma.

We explain how Louis Pasteur’s work on fermentation led Lister to use carbolic acid at the Glasgow Royal Infirmary, where he treated compound fractures that once meant amputation. We also cover his sterile catgut sutures, the carbolic spray, fierce resistance from surgeons, nurses, and students in London, his partnership with his wife Agnes, and the honors that followed, from Westminster Abbey to the Listeria genus and Listerine.

• Why the miasma theory seemed logical to Victorian doctors
• How his father’s microscope work shaped Lister’s cellular view of medicine
• The link Lister drew between Pasteur’s fermentation research and gangrene
• Carbolic acid, catgut sutures, and the proof found in compound fractures
• Why the medical establishment resisted antiseptic surgery so fiercely