All Hail the Germ Theory of Disease

Microbes in the Gut Help Determine Risk of Tumors

Transferring the gut microbes from a mouse with colon tumors to germ-free mice makes those mice prone to getting tumors as well, according to the results of a study published in mBio®, the online open-access journal of the American Society for Microbiology. The work has implications for human health because it indicates the risk of colorectal cancer may well have a microbial component.

Sounds simple enough.  Robert Koch used the same method to determine infectivity in the 1800's.   Somebody wanna tell me why this experiment wasn't done decades ago?????