80 IMMUNITY IN HEALTH 



that no normal appendix can be completely straight- 

 ened in situ. However, it is not the vessels in its 

 mesentery, but it is the appendix itself which is bent 

 and bent to a far less extent than are many other por- 

 tions of the alimentary tract. The vermiform process 

 has, however, a terminal blood supply with no 

 collateral circulation ; that is, its vessels do not freely 

 anastomose with vessels of adjacent adoral and adanal 

 gut, as is the case with the rest of the alimentary canal. 

 There is theoretical ground, then, for suspecting that 

 the absence of a free collateral circulation predisposes 

 the vermiform process to attacks of congestion, and so 

 perhaps to bacterial invasion. Foreign bodies have 

 been recorded in a small but sufficient percentage of 

 cases to give rise to the belief that they encourage 

 appendicitis.* Just as fig seeds have been found in the 

 lacunae of diseased tonsils (Pybus, 1915). Yet in 

 neither case can one suppose that foreign bodies are 

 the usual cause of disease in these structures. Bruising 

 of the walls might well follow the attempts of the vermi- 

 form appendix to rid itself of the foreign body, and 

 bruising would certainly favour bacterial invasion. 

 Yet, it must not be forgotten that previous ulceration 

 of the appendix is liable to be followed by a stricture, 

 and an appendix with a stricture may act as a trap 

 for foreign bodies. It is highly probable that the 

 faecal concretions found in many cases of appendicitis 

 follow previous stricture of the lumen. Caecal contents 



* The followinji: foreign bodies in diseased appendices have been 

 recorded : — game-shot, pins, bristles, hairs, round worms, thread 

 worms, cherry stones, grape stones, date stones, orange pips, and 

 fragments of nutshells. 



It must however be remembered that concretions have very often 

 been mistaken for fruit stones. Treves, in 1896, in remarking that 

 he. personally, had never foimd a genuine foreign body in the appen- 

 dix, drew attention to the wonderful way in which appendicular con' 

 pretions mjmicked certain seeds and fruit-stones. 



