The Digestive System. 57 



distensible, its function, however, is unknown. It is 

 surmised by some that the blood plates (corpuscles) have 

 their origin in the spleen, by others that the spleen is 

 the graveyard of these corpuscles 5 be that as it may, in 

 certain diseases (Anthrax, Actinomycosis, Glanders) the 

 condition or appearance of the spleen is of value in the 

 recognition (diagnosis) of the disease. It has been stated 

 that the entire digestive tract is lined by mucous mem- 

 brane. 



Absorption. The lacteals originate in villi, finger-like 

 projections of the mucous membrane, which tend to give 

 it a pile. Each villus contains blood vessels, nerves and 

 lymphatics; to illustrate introduce a finger into a glove, 

 the glove material represents the mucous membrane, the 

 glove finger a villus, and the finger the blood and lym- 

 phatic vessels and nerves. These villi are most abundant 

 in the small intestines, a few being found in the blind 

 gut (coecum) and a few in the large gut (great colon). 

 The coecum is situated in the right flank of the animal, 

 is quite large, is directed downwards and terminates by 

 a blind extremity; it receives two openings, one from 

 the small intestines which is guarded by a valve, the 

 other from the large colon. The great colon occupies 

 the central portion of the abdomen, is arranged in four 

 parts, two of which lie on the other two; its external sur- 

 face is marked by strong muscular bands. 



The taking in of the prepared food products is per- 

 formed by the blood vessels and the lacteals, which con- 

 stitute the entrance to the lymphatic system. The great 

 colon acts as an organ of absorption in horses; digestion 

 does not take place in the colon, although absorption 



