THE ANATOMY OF THE HORSE «1 
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 
