It's suddenly occurred to medicine that that "useless" appendage, the appendix, is nothing of the sort, and in fact plays a vital role in maintaining good gut bacteria. It seems to be a 'safe house' where good bacteria can go during bouts of diarrhea, for instance.
The appendix contains immune system tissue, which are there to protect the good bacteria in the gut, believes William Parker, assistant professor of experimental surgery at Duke University Medical Center.
Prof Parker came up with the theory after studying the gut, and the symbiotic relationship of microbes in the gut and bowel.
It's role may be nullified by modern society and its advanced medical care and sanitation, which would explain why the appendix can be removed without causing any obvious difference to the person's wellbeing.
(Source: Journal of Theoretical Biology, 2007; published online, September 7).