(I) The appendix or blind gut, is a structure of interest and sometimes concern. (II) As a result, man cannot digest the cellulose which is the main constituent of plant cell walls. (III) In the human body it is regarded as a useless relic, and its removal is often beneficial. (IV) The case is very different among herbivorous animals. (V) In the rabbit, for instance, the appendix is a very large organ, and hibernating animals fill it with food before their winter sleep.