CHAPTEE III. 



THE DIGESTIVE SYSTEM. 



An acquaintance with the arrangement and methods 

 of working of the digestive organs is essential to the 

 feeder of fat stock, the feeder of dairy stock and the per- 

 son who feeds for work. It has been found that the 

 higher the organization the more complicated is the 

 digestive process. In order to render the process easily 

 understood four divisions or stages are outlined, as fol- 

 lows : 



1. Prehension and Mastication, referring to the seizing 

 and chewing of food, the preparatory stage calling into 

 employment the lips, tongue, teeth and glands of the 

 part. 



2. Secretion, the process of saturation of food mate- 

 rials with the digestive fluids (gastric juice, bile, pan- 

 creatic juice). 



3. Absorption, referring to the taking into the system 

 of the prepared materials obtained from the food, employ- 

 ing such tissues as the blood and lymphatics. 



4. Excretion, the process of throwing out, by means 

 of the excrements (feces and urine), sweat, and breathed 

 air, the waste material, that part of the food from which 

 the nourishment has been extracted. It does not follow 

 that this latter is always the case, e. g. , the profit obtained 

 by letting shoats follow steers, showing that a large part 

 of the food was not used by the steers. 



