Dr. Bill Parker, is right about this, and I have advance the same theory (more or less) myself for about 40 years. I never went with the "vestigial organ" idea. My thinking was that as soon as our bodies note a gut infection the appendix is sort of “valved” off, and the body does its wash out procedure etc. The good guys in the appendix are protected from the body’s antibiotic defenses, and the physical wash out, and the bad gut bugs etc. And when things are under control & safe for the good guys they are turned loss again. I do not believe we have any "vestigial organ" and I have reasons (possible ones) for the other so-called “vestigial organ".

R. Carlson