I call to mind the case of one adult male I interviewed in one of the smallpox hospital wards at that time. He was vaccinated in infancy, had smallpox when eight years old, and was subsequently re-vaccinated three times. That man died of smallpox. I have visited Glasgow in two of its smallpox epidemics. Nothing but sweeping away, the rookeries, where smallpox invariably, takes hold, can ever save those parts of the city from periodical visitations.
Space forbids further reminiscences but it is the same story everywhere.
Go back to the records of Old London and we find insanitation and smallpox keeping company throughout. It is only in unsanitary quarters it can gain a hold. Smallpox, typhus, and other fevers occur in common conditions of foul air, stagnant putrefaction, bad house drainage, sewers of deposit, excrement sodden sites, filthy street surfaces, impure water, and overcrowding, and the entire removal of such conditions is the effectual preventive of diseases of those species, whether in ordinary or extraordinary visitations. However, it is interesting to review what some physicians were writing about smallpox vaccination three generations ago. It is clearly obvious from these writings and common sense that hygiene and nutrition have enormous influences on the course of not only smallpox, but nearly every infectious illness.