A study on 'Vermiform Appendix'--a caecal appendage in common laboratory mammals.

The vermiform appendix, a small structure without any known function in human being has been regarded as a vestigial remnant of a more developed distal caecum in man's herbivorous ancestors. A detailed study of the morphological and histological changes in the appendix and the caecum of different mammals with varying dietary habits revealed a distinctly well-defined vermiform appendix in rabbit only. However, the apical part of caecum among the carnivorous animals like cat and dog showed a clear histological picture with heavy infiltration of lymphoid tissue in the mucous & sub-mucous coats as seen in rabbit or human being. Thus, the vermiform appendix is in no way a vestigial organ but a specialized structure without any definitely known function, probably concerned with the establishment and maintenance of the body defence and immunity of the body.