THE LIVER PANCREAS SPLEEN OMENTUM. 213 



dnimal, by the aid of the diaphragm and the muscles of the 

 belly, presses upon them, and they are evacuated. A curious 

 circular muscle, and always in action, called the sphincter (con- 

 strictor muscle), is placed at the anus, to prevent the constant 

 and impleasant dropping of the faeces, (dung) and to retain them 

 mitil the horse is disposed voluntarily to expel them. 



THE LIVER. 



Between the stomach and the diaphragm-^its light lobe or 

 division in contact with the diaphragm, the duodenum and the 

 right kidney, and the middle and left divisions with the stomach 

 — is the liver. It is an irregularly-shaped, reddish-brown sub- 

 stance, of considerable bulk, and performs a very singular and 

 important office. 



The blood brought back by the veins from the stomach, intes- 

 tines, spleen, pancreas, and mesentery, instead of flowing directly 

 to the heart, pass first through the hver. As the blood traverses 

 this organ, the bile is separated from it, and discharged through 

 the hepatic d/uct directly into the duodenum, without the inter- 

 vention of any gall-bladder, as is found in most animals. The 

 bile is probably a kind of excrement, the continuance of which 

 La the blood would be injurious, and it doubtless aids in the pro- 

 cess of digestion. 



THE PANCREAS. ' 



In the domestic animals wliich are used for food, this organ is 

 called the sweet-bread. It hes between the stomach and left 

 kidney. It secretes a fluid which is carried into the intestines 

 by a duct which enters at the same aperture with that from the 

 liver. The specific use of this fluid is unknown, but is clearly 

 employed in aiding the process of digestion. 



_ THE SPLEEN. 



This organ, often called the melt, is a long, bluish-brown sub- 

 stance, broad and^ thick at one end, and tapering at the other ; 

 lying along the left side of the stomach, and between it and the 

 short ribs. The particular use of this organ has never been 

 clearly ascertained, for in some cruel experiments it has been 

 removed without apparent injury to digestion or any other iuno- 

 lion. 



THE OMENTUM. 



Or cawi, is a doubling of the peritoneum, or rather consists ol 



