THE SEROUS TISSUE. 81 



2d. The synovial membranes. 



3d. The bursae mucosae. 



The form of the serous tissue has been stated to be that 

 of shut sacs this is true of all except the peritoneum of the 

 female, which is open at the extremity of the fallopian tubes. 

 These sacs all line the various cavities in which they are 

 found, and are thence reflected upon the various organs 

 and viscera. These reflections have different names, ac- 

 cording to their situation, uses, attachments, &c., as the 

 omentum gastro-hepaticum or minus, omentum gastro- 

 colicum or majus, gastro-splenicum, mesentery, meso-colon, 

 meso-rectum, the ligaments of the liver, the broad liga- 

 ments of the uterus, the ligaments of the bladder, &c., all 

 of which are the names of so many reflections of perito- 

 neum, illustrating its position and connection with the 

 stomach, liver, intestines and other organs. 



The serous tissue, with some few exceptions, forms a 

 complete investment to all the organs and parietes of cavities 

 with which it is connected ; that portion surrounding the 

 walls is the. parietal, that covering the several organs is 

 the visceral layer. Its continuity as one unbroken mem- 

 brane, except the female peritoneum, is admitted by all 

 anatomists, and it is said to have been successfully dis- 

 sected, entire and complete, without the slightest rupture, 

 from the abdominal cavity and its various organs, by one 

 Nicholas Massa. 



How the peritoneum, pleura, &c., shall cover the several 

 viscera, and yet these same viscera be upon the outside of 

 its cavity, is often a difficulty with the young beginner in 

 anatomy. The comparison with the double night-cap, is 

 used as an easy and familiar illustration. That part of 

 the cap which covers and fits close to the head, represents 

 the peritoneum covering the different organs, while the por- 

 tion that floats loose above the head, and is external, repre- 

 sents the peritoneum lining the interior abdominal walls. 

 Now it is plain that the head, though covered by the cap, 

 is not in its proper cavity, but on the outside. And so with 

 the peritoneal sac, all the organs are upon the outside, and 

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