Ignaz Semmelweis tried to convince the medical establishment that washing hand stop’the spread of disease in hospitals. His colleagues responded that doctors are gentlemen and gentlempdo not have dirty hands. Semmelweis was committed to a mental institution soon after and died from an infection as a result of a beoti’he received from institution workers. A few decades later the four humors school of medicine was replaced with diseases caused by microorganisms.
Imagine living at a time when the germ theory of disease wasn’t widely accepted. You might even need to convince people that microbes exist. If they already know about microbes, they might believe that microbes spawn out of thin air through abiogenesis. Previously that word was used when talking about microbes spoiling food whereas nowadays it’s applied to the early stages of the earth.