204 



THE HORSE. 



nutritive part of the food, and a yellow pulpy substance, wliich becomes tho 

 excrement. As these matters pass on by the motion of the intestines, the 

 separation becomes more complete; the chyle is gradually taken up by the 

 mouths of these numerous little vessels, which are called the lacteals, and at 

 length the excrement alone remains. 



The next portion of the small intestine is the jejunum, so called be- 

 cause it is generally empty. The passage of the food seems to be very 

 rapid through it. It is smaller in bulk, and paler in colour, than tho 

 duodenum. 



To this succeeds the ileum ; but there is no point at which it can be said 

 that the jejunum terminates and the ileum begins, except that the latter is 

 said to be about one-fifth longer than the former. The whole of these small 

 intestines will contain about eleven gallons of water. 



At the termination of the ileum, d, commence the large intestines. The 

 first of them is the coecum (blind), c; it has but one opening into it, and 



consequently every thing that passes* 

 through it, having reached the blind 

 or closed end, must return, in order to 

 escape. It is not a continuation of 

 the ileum, but the ileum pierces the 

 head of it, as it were, at right angles, 

 (d,) and projects some way into it, 

 and has a valve at its extremity; so 

 that what has traversed the ileum, 

 and entered the head of the colon, 

 whence the ccEcum rises, cannot re- 

 turn into the ileum. Along the outside 

 of the coecum run three strong bands, 

 each of them shorter than that intes- 

 tine, and therefore puckering it up, 

 ftiid forming it into three separate sets of cells, as shown in the accompany, 

 ing side-cut. 



That portion of the food, then, which has not been taken up by the 

 lacteals or absorbent vessels of the small intestines, passes through this 

 valvular opening of the ileum, and a part of it enters the colon, while the 

 remainder flows into the coecum. Then, from this being a blind pouch, 

 and from the cellular structure of this pouch, the food must be detained 

 in it a very long time ; and in order that, during this detention, all the 

 nutriment may be extracted, the coecum and its cells are largely supplied 

 with blood-vessels and absorbents. It is principally the fluid part of the 

 food that seems to enter the coecum. A horse will drink at once a great 

 deal more than his stomach will contain ; or, even if he drinks a less 

 ijuantity, it remains not in the stomach or small intestines, but passes on to 

 ihe caecum, and there is retained, as in a reservoir, to supply the wants of 

 the system. In his state of servitude, the horse does not often drink more 

 than twice or thrice in a day ; and the food of the stabled horse being 

 chiefly dry, this waler-slomach is most useful to him. The coecum will 

 liold four gallons. 



The greater portion of the food, and the more solid part of it, goes on to 

 tho colon, if 4'. This is an intestine of exceedingly large dimensions; it 

 is capable of containing no less than twelve gallons of liquid or pulpy food. 

 At its union with the coecum and the ileum, although larger than the 

 latter intestine, f, it is of comparatively small bulk, but it soon swells 

 lilt to an rnornious extent. It has likewise, in the greater part of its 

 course, thrt'c bands like tlic ca-cutn, uhieh also divide it internally into the 



