CHAPTEE IV. 

 EXCRETION. 



The expulsion of waste products from the body is by v 

 means of a, the feces (dung); 6, the urine ; c, the sweat; 

 d, respired (breathed) air, and is termed excretion. 



A. By the feces (dung). In the description of the 

 digestive tract the food had to be taken as far as the 

 great colon, where it was stated some absorption might 

 take place, from there back, however, the remainder 

 of the food ingested cannot be acted upon for various 

 reasons, such as the previous extraction of all the 

 nutritive matters, etc. The division of the intestinal 

 canal behind the great colon is the floating colon, located 

 in horses in the left flank, in cattle and sheep the upper 

 part of the left flank is occupied by the paunch. This 

 colon has a number of tightenings (constrictions) in its 

 walls, due to certain circular muscular fibres. It will be 

 remembered that the entire intestinal tract is a musculo- 

 membranous tube, and that long and circular muscular 

 fibres enter more or less into the construction of it. It 

 has also been stated that muscles contract and relax, 

 hence it would be expected that the intestines would 

 have a certain amount of movement, such is true, there 

 is a constant worm-like motion in the intestinal walls 

 during life unless paralyzed; such movement is known 

 as peristalsis, or the peristaltic, (vermicular or worm-like) 

 movement of the bowels. As a result of this movement 



