328 STRUCTURE OF THE SHEEP. 



pare it for the separation of the chyle which may be seeii on 

 the surface of the food. For this purpose it is largely sup- 

 plied with an alkaline fluid, which unites chemically with the 

 acid of the chyme. The quantity of bile secreted by the 

 sheep in 24 hours is very considerable, probably from 3 lbs. 

 to 5 lbs. ; but we are not to suppose that its sole use is that 

 above stated, for it has been proved that the bile does not 

 pass away with the excrements, but is again taken into the 

 S3^stem to perform an important office to be noticed when we 

 speak of the circulation. Thus the liver separates that 

 which would be detrimental to the blood, and it supplies 

 what is wanted for digestion as well as for another important 

 process in respiration. 



Besides the bile the duodenum receives a copious supply 

 of fluid of a thin watery nature from the pancreas. This 

 fluid closely resembles the saliva, and its principal use ap- 

 pears to be to liquify the contents of the intestines. 



The remaining part of the small intestines understood un- 

 der the terms jejunum and ileum are confined to, and con- 

 nected with, the spine by means of a thin transparent mem- 

 brane called the mesentery, which not only supports the in- 

 testines, but prevents their entanglement, and serves as the 

 vehicle by means of which the arteries, veins, nerves, and 

 absorbent vessels are transmitted to and from the bowels. 

 Amongst these there are some very minute, though very 

 numerous vessels called the lacteals, whose office it is to 

 convey the chyle, a Avhite milky liquid resembling albumen, 

 from the intestines to a duct termed the thoracic, which 

 passes along the spine and terminates in a large vein just 

 previous to its arrival at the heart. 



The composition of the chyle is very similar to the blood, 

 differing from it in little more than the absence of its color- 

 ing principles. The lacteals, of course, open into the inner 

 coat of the intestines, and the greater portion of the chyle 

 is taken from the food in the small intestines and in the ear- 

 liest portion of them in the greatest degree. The small in- 

 testines are remarkably long in the sheep, exceeding, indeed, 

 sixty feet, and this great length renders them capable of con- 

 taining much more than the large guts. 



In man, the large intestines are distinguished as the cmcum, 

 the colon, and the rectum ; in the horse, these divisions like- 

 wise obtain, and with much more propriety than the artifi- 

 cial distinctions of the small guts. The caecum and the 



