534 DIGESTION. 



thence through the pelvis, along the hollow of the sacrum, to terminate 

 at the anus. Like the small intestine it is divided into three portions ; 

 the caecum, colon, and rectum. 



The caecum or blind gut is the part of the great intestine into which 

 the ileum opens. It is about four fingers' breadth in length, and nearly 

 double the diameter of the small intestine. It occupies the right iliac 

 fossa, in which it is bound down, so as not to be able to change its 

 position. The extremity of the ileum joins the caecum, at an angle; 

 and if we examine the interior of the caecum, at the point of junction, 

 we find a valvular arrangement, which has been called valve of Tulpius, 

 valve of Bauhin, ileo-csecal valve, &c. Fig. 244 exhibits the nature of 

 this arrangement. At the point of union of the two intestines, a soft 

 eminence exists, flattened from above to below, and elliptical trans- 

 versely, which is divided into two lips. One of these seems to belong 

 to the ileum and colon hence called ileo-colic; the other to the ileum 

 and caecum, and termed ileo-csecal. From the disposition of these lips 

 a valve results, so constituted, that the lips, which form it, separate 

 when the faecal matters pass from the small to the large intestine; 

 whilst they approximate, cross, and completely prevent all retrogression, 

 when the faeces tend to pass from the great intestine to the small. At 

 the extremities of the valve are small tendons, which give it strength, 

 and have been termed frsena or retinacula of the valve of Bauliin. 



Although this valvular arrangement prevents the ready return of' 

 the excrementitious matter into the small intestine, we have many 

 pathological opportunities for discovering that it is not effectual in all 

 cases. In stricture of the large intestine, stercoraceous vomiting is a 

 frequent phenomenon, and there have been cases of substances, thrown 

 into the rectum, having been evacuated by the mouth. 



At the posterior and left side of the caecum, a small process detaches 

 itself, called, from its resemblance to a worm, appendix vermiformis; 

 and, from its connexion with the caecum, appendix cseei. It is convo- 

 luted, variable in length, and attached, by its sides, to the caecum. 

 Its free extremity is impervious; the other opens into the back part of 

 the caecum. This appendage has all the characters of an intestine. 

 Various hypotheses have been indulged regarding its uses. Some have 

 conceived it to be a reservoir for the faeces ; but its diminutive size, in 

 the human subject, precludes this idea: others have thought, that it 

 secretes a ferment, necessary for faecal formation; and others, again, a 

 mucus for preventing the induration, that might result from the deten- 

 tion of the faeces in the caecum. The opinion that it is a mere vestige 

 of the useful and double caeca, which exist in certain animals is as 

 philosophical as any. M. de Blainville, 1 indeed, regards it as the true 

 caecum; and what is named the caecum as the commencement of the 

 colon. It is manifestly of little importance, as it has been found 

 wanting or obliterated in many subjects, and has been extirpated 

 repeatedly with impunity. The caecum is said to be wanting in all ani- 

 mals that hybernate. It is small in the Carnivora; very large and 

 long in the Solidungula, Ruminantia and Rodentia; in which, as will 



1 De 1'Organisation des Animaux, &c., Paris, 1825. 



