PREVIOUS THEORIES 11 



colon undergo inspissation prior to their discharge per 

 anum. In other words the caecum and ascending colon 

 have physiologically to undergo great variation in the 

 volume of their contents. It would be to the detriment 

 of their functions were they to be acutely susceptible 

 to pressure changes, were they to undergo peristalsis 

 and void their contents immediately they became filled 

 from the ileum. We must regard them thus, as in the 

 normal state distinctly irresponsive to pressure effects. 

 It is the appendix we hold that is the hydrostatic agent 

 initialling peristalsis in the large gut. In it we have 

 a narrow tube, with no such pronounced variations 

 in calibre, so situated that the weight of the column of 

 forming faeces is communicated to it, and we presume 

 that when this weight reaches a certain point, the dis- 

 tending force acting upon its walls, originates muscular 

 contractions which spread directly into the caecum and 

 so initiate the forward movement of their contents. 

 Such a view explains the tendency to constipation in 

 the bed-ridden, in whom the gravitational effect of the 

 contents of the ascending colon can have little effect; 

 it explains the normal tendency to empty the bowels, 

 either shortly after rising and assuming the erect posi- 

 tion or after the first meal when stimulating peristalsis 

 of the small bowel has driven extra contents into the 

 caecum and so increased the load, it explains the con- 

 stipation that tollows some interval removals of the 

 appendix." 



This view takes no account of the lymphoid tissue 

 in the wall of the appendix, of the presence of the ap- 

 pendix in many four-footed animals, nor of the import- 

 ance of the ileo-caecal sphincter in initiating peristalsis 

 of the large bowel. Moreover the usual experience is 

 that appendicectbmy tends to relieve rather than to 

 cause constipation. 



