THE ANATOMY OF THE HORSE 6l 



being the passage into the womb from the outside. The 

 bones which help to form the hip cavity are situated at the 

 sides and at the back immediately under the tail is what is 

 known as the anus. The use of the rectum is to hold the 

 balls as they pass back from the floating colon. When the 

 rectum becomes so full that there is pressure on the sides of 

 the wall thus stimulating the nerves the muscular coat con- 

 tracts and forces the contents back toward the anus. At the 

 same time the muscles of the anus dilate or open, causing 

 the faeces or manure to pass out. 



II. — THE GLANDS CONNECTED WITH THE DIGESTIVE SYSTEM. 



The glands which assist in digestion are the liver, the 

 pancreas and the spleen. 



8. The Liver is the largest gland in the body and is situ- 

 ated between the stomach and the diaphragm. The liver of 

 the horse weighs from ten to twelve pounds. It is of a dark 

 brown color, well supplied with muscles and nerves, and is 

 held in place by several strong ligaments. A bitter, greenish 

 colored fluid called the bile is secreted from the liver and 

 emptied into the digestive system where it plays an important 

 part in its action on the food. There is no gall bladder in 

 the horse but simply a tube passing from the liver to the 

 small bowel into which it empties the bile about six inches 

 behind the stomach. It is important to note that it is in this 

 tube that gall stones sometimes collect. 



9. The Pancreas is another very important gland. It is 

 of a grayish, fatty color, and may be found near the back- 

 bone in front of the_ kidneys. The pancreas secretes a clear, 

 colorless fluid called the pancreatic juice. This fluid, like 

 the bile from the liver, also plays an important part in the 

 digestion of the food. It is carried down from the pancreas 

 by a duct or tube emptying into the small bowel just behind 

 that from the liver. 



10. The Spleen is a long, flat gland about fifteen inches 

 in length, situated along the left side of the stomach and to 

 which it is closely attached. It is of a grayish red color and 

 feels quite soft. It is ductless, there being no secretion 

 passing from it. The function of this gland is not clearly 

 understood, but by many it is supposed to regulate the tem- 

 perature of the stomach during the process of digestion and 

 to act as a reservoir for the blood. Some speak of it as the 



