68 



MANUAL OF CATTLE-FEEDIIS-G. 



Fig. o shows a longitudinal section of a villns, in wliieli 

 a represents tlio epitlielial cells, h the capillary blood-\ es- 

 sels, the lajer of muscular libres, and d the lacteal. 



Lacteals and Blood-Vessels.-™The 

 lacteals unite into larger ones leading 

 to the mesenterio ffkmds, and after 

 leaving these, finally join the thoracic 

 duei, a large vessel leading forward (in 

 man upward) and emptying into a vein 

 in the left side near the collar-hone, 

 called the left sulclavlan vem, near its 

 entrance into the heart. 



They derive their name from a milky- 

 looking fluid wath which they are filled 

 during digestion, and which ow^es its ap- 

 pearance to the digested and emulbificd 

 fat of the food which has been resorbed 

 from the chyle. At other times they 

 contain a clear or opalescent li(piid 

 called lympli. 



The capillaries of the intestines also unite into larger 

 vessels, and finally into one, the jpoHal vein, leading to the 

 liver. (Compare fig. 4, p. 77.) There the blood which 

 it carries is distributed through a second set of capillaries 

 in that organ, and then reunited again into a single vein, 

 the IhejyatiG veitij leading almost directly to the heart. 



Phenomena of Resorption. — As soon as the food 

 passes from the stomach into the intestines, the resorbents 

 of the latter begin their work, and the two processes of 

 digestion and resorption go on simultaneously. 



Ouj' knowledge of the processes of resorption is not as 

 full as might be wished. We know that liquids and soluble 

 substances brought into the intestines, rapidly disappear 



Fig. 3,— (Irey). Villus." 



