The large bowels have three coats, the same as the small ones. The first part of the large bowels is known as the blind bowel or caecum, and is about three feet in length; this is generally the first thing to protrude when opening a horse’s abdominal cavity. Its use is to act as a reservoir to hold the water and fluid of the food; from this organ the water and fluid parts are mostly taken up into the system. The next part of the large bowels is known as the large colon; it lays along the floor of the abdominal cavity, is about nine feet in length and is doubled on itself three times. In this bowel the solid part of the food is found. Here digestion is brought about by the contraction and expansion of the muscles of the bowel and the nourishment taken from it, after which it is worked back out of this bowel and enters what is known as the floating colon. This is about ten feet in length and about two inches in diameter, or double the size of the small bowel. It is thrown into folds or pleats, and as that portion of the food containing no nourishment passes through it is worked into balls which pass back and are emptied into the rectum or back bowel. This is situated at the back part of the abdominal and pelvic cavity back of the small bowels or intestines and like them, is suspended by a fold paritoneum. The rectum or back bowel is sometimes known as the straight bowel. It is about 18 inches long and forms the last part of the bowels or intestines. Its coats are a continuation of those of the large bowel, but each is thicker and heavier. Above this bowel are the bones of the sacrum, below it, in the horse the bladder and other small glands. Below the rectum of the mare are situated the womb and the vagina, the latter being the passage into the womb from the outside. The bones which help to form the pelvic cavity are situated at the sides, and at the back immediately under the tail is what is known as the annus. 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 contracts and forces the contents back towards the annus. At the same time the muscles of the annus dilate, causing the faeces to pass out. ACCESSORY ORGANS OF DIGESTION.--In the abdominal region these organs are the Liver, the Pancreas, and the Spleen.