<Li> The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms . </Li> <Li> The microorganism must be isolated from a diseased organism and grown in pure culture . </Li> <Li> The cultured microorganism should cause disease when introduced into a healthy organism . </Li> <Li> The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent . </Li>

When was the germ theory of disease proposed and on what basis