Germ Theory of diseases by Robert Kooch

Robert Kooch has great contributions in field of micobiology.He formulated his Germ theory of diseases which has following four postulates.

1. A specific organisms can always be found in association with given diseases.
2. This organism can be isolated and grown in pure culture in laboratory
3. When this pure culture is inoculated into a healthy animal it produces disease.
4. This organism can be recovered in pure culture from the experimentally infected animal.