OF THE INTESTINES. 255 



becomes a more liquid pulp, equally mixed, of a grey 

 colour, and acidulous odour : in the ileum it begins to 

 separate into two parts — into the faeces, of a pale, yel- 

 lowish, brown, colour,* and nauseous smell — and the 

 genuine chyle, swimming upon the former, extracted 

 from the chyme, separated by the bile from the 

 faeces, and destined for absorption by the lacteal 

 vessels, as we shall find in the next section (A). At 

 present, we shall enquire what course is taken by 

 the faeces. 



413. These, after becoming more and more inspis- 

 sated in their long course through the ileum, have to 

 overcome the valve of the colon and pass into the large 



* We formerly (387) remarked, that the bilious colour of the faeces arose 

 from the excrementitious part of the bile. In the jejunum, the bile being 

 undecomposed and mixed with the equable pulp of the intestines, and conse- 

 quently diffused and diluted, cannot exhibit its true colour. But after its sepa- 

 ration into two parts, the excrementitious portion, mixed with the precipitated 

 faeces, and, as it were, again concentrated, now discovers its original colour, and 

 imparts it to the faeces. 



C. F. Wolff {Act. Petropolit. 1779. P. ii. p. 245.) entertains a different opi- 

 nion in regard to the cause of the bilious colour of the faeces contained in the 

 ileum. He conceives that an addition of bile occurs near the extremity of the 

 jejunum, by exhaling from the gall-bladder and penetrating this part of the 

 intestine and its contents. This bile differing, perhaps, in its nature, from the 

 bile of the choledochus, and not being mixed with the faeces as the latter is with 

 the chyme, retains its colour through all the remaining tract of the intestines 

 and continues pure bile. 



But, besides our being able easily to explain why this colour is not observable 

 before the decomposition of the chyme and bile, it is extremely doubtful whe- 

 ther, during life and health, any exhalation can occur from the gall-bladder and 

 penetrate the intestine. For in subjects recent and scarcely cold, the intestines 

 are but slightly tinctured with bile, although they are dyed with it very deeply 

 and extensively after a lapse of some hours or days, i. e after the coats of the 

 gall-bladder have lost their tone and become incapable of preventing the trans- 

 udation of tbeir contents. 



