THE PERITONEUM. 25 



The peritoneum, which covers the stomach, is extended from 

 the great curvature of that organ so as to form a large mem- 

 brane, which descends hke an apron before the intestines. This 

 process of peritoneum is composed of two lamina, so thin and 

 delicate as to resemble cellular membrane, which, after extend- 

 ing downwards to the lower part of the abdomen, are turned 

 backwards and upwards, and proceed in that direction until 

 they arrive at the colon, which they enclose, and then continue 

 to the back of the abdomen, forming the mesocolon. The part 

 of this process which is between the stomach and the colon, is 

 called Epiploon or Omentum. 



This extension of a membrane, from the surface of a cavity 

 which it lines, to the external surface of a viscus in that cavity, 

 is called by some anatomists, "reflection;" and the technical 

 term rejlected membrane is therefore applied to a membrane 

 distributed like the peritoneum. 



It must be evident that this distribution of the peritoneum is 

 very complex, and that it is not easy to form an accurate con- 

 ception of it from description, but it can be readily understood 

 by demonstration ; therefore no farther account of its arrange- 

 ment will now be attempted, but each of its processes will be 

 considered with the organs to which they are particularly 

 subservient. 



That portion of the peritoneum which lines the abdomen, 

 and covers the viscera, is thin and delicate, but very firm. It 

 yields to distension, as in pregnancy, ascites, &c., and again 

 recovers its dimensions. It was formerly thought to be com- 

 posed of two lamina, but this cannot be proved. The internal 

 surface of this membrane is very smooth, and highly polished ; 

 and from it exudes a liquor which is well calculated for lubri- 

 cation, and barely sufScient to keep the surface moist during 

 health ; but sometimes it is very abundant, and occasions the 

 aforesaid disease — ascites. This fluid appears to exude from 

 the surface of the peritoneum when it is compressed in a living 

 animal, or one recently dead. It is probably effused from the 

 extremities of arteries, for an effusion takes place when water is 

 injected into these vessels. 



VOL. II. 3 



