CHAP. XXV.] DIGESTION IN THE LARGE INTESTINE. 265 



disease, and after death no lesion is discoverable, but slight enlarge- 

 ment of the liver * 



We have already remarked that the venous blood of the spleen 

 passes along with that from the stomach and intestines through the 

 liver. Recent researches of Kolliker and Ecker offer some expla- 

 nation of this fact, and at the same time of the relation between 

 hsematine and the colouring matter of bile, as well as between the 

 office of the liver and the generation of the red particles of the blood. 

 It would appear from these researches, which will be detailed when 

 we come to treat of the spleen, that the red blood- corpuscles 

 undergo decay in the red substance of the spleen, giving up their 

 hsematine in an altered form to the portal blood, from which it may 

 not improbably, as Kolliker conjectures, pass into the bile-cells to 

 form, and to be eliminated as, the biliary colouring matter ; and, 

 perhaps, also to contribute to supply hsematine to new blood-cells 

 developed in the liver.f 



Of Digestion in the Large Intestine. The contents of the large 

 intestine, which constitute the fceces properly so called, differ much 

 from those of the small intestine. Generally, and in the normal 

 state, they are more solid, more homogeneous, exhibiting a certain 

 form, which is determined by the size and shape of the cells of the 

 colon. These characters are more marked the further the faeces 

 have advanced in the colon. 



The changes, upon which depends the difference of character of the 

 contents of the large and small intestine, commence in the ccecum. 

 Many facts lead to the opinion that the intestinal contents undergo 

 some further digestion in the ccecum, analogous to that of the 

 stomach. Schulz affirms that an acid fluid is secreted by the mucous 

 membrane of the ccecum, which is more distinct in herbivora than 

 in carnivora : Bernard and Blondlot state that the acidity of this 

 fluid is due to the presence of lactic acid, J In dogs, we have found 

 that litmus applied to the surface of the coecal mucous membrane 

 became reddened in some, but not in others; a difference probably 

 depending upon some peculiarity in the food or the time of digestion. 

 The remarkable development of the ccecum in some animals as 

 compared with others, denotes that it must exercise some special 

 function. In herbivora its size is especially large ; in carnivora, it 

 is small. Moreover, the mucous membrane of the coecum resembles 



* Kolliker iiber die Blutkorperchen der Menschlichen Embryo und die 

 Entwickelung der Blutkorperchen der Saugethieren. 

 t Cycl. Anat. and Phys. ; art. Spleen. 

 Gazette Med. de Paris, 1844. 



VOL. II. T 



