The Appendix -
now known to be an important part of what is called the reticulo-endothelial system of the body. Like the tonsils, the appendix fights infection.
"For at least 2,000 years, doctors have puzzled over the function of the thymus gland. Modern physicians came to regard it, like the appendix, as a useless, vestigial orgin, which had lost its original purpose, if indeed it ever had one. In the last few years, however..men have proved that far from being useless, the thymus is really the master gland that regulates the intricate immunity system which protects us against infectious diseases..Recent experiments have lead researchers to believe that the appendix, tonsils and adenoids may also figure in the antibody responses." *"The Useless Gland that Guards Our Health", in Reader's Digest, November 1966.
Much more from The Evolution Handbook pages 720 and 724