http://www.sciencedirect.com/science?_ob=ArticleList...

Biofilms in the large bowel suggest an apparent function of the human vermiform appendix
Journal of Theoretical Biology, In Press, Accepted Manuscript, Available online 7 September 2007,
R. Randal Bollinger, Andrew S. Barbas, Errol L. Bush, Shu S. Lin and William Parker