Smallpox pustule gauge, Edinburgh, Scotland, 1870-1930

It’s 1873, and you’ve just moved to London from the small country town where you grew up. The trouble is, you were never vaccinated against smallpox. Are you at risk? There is no telltale scar anywhere on your arm and no record of it being done – and it’s the law! Besides, since the epidemic of 1871 – which killed 50,000 people – your father has changed his anti-vaccination views. Once your local …