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