SECTION OF ABDOMEN. 



197 



through between them. Do the same with the hinder part of 

 the large intestine, the Rectum, and sever it. Kemove the 

 stomach and intestines, carefully cutting the mesentery -along 

 the whole attachment to the intestines, and uncoil the latter. 

 How many times is the length of the body, including the 

 head, contained in the length of the intestine ? Compare the 

 lengths of the small intestine, cecum, and large intestine. 

 Cut out about an inch of the small intestine in the middle of 

 its course, slit it open lengthwise, wash it thoroughly, and 

 with a lens examine its inner surface under water, to see the 

 thread -like projections, or Villi. In the same way examine a 

 piece of the large intestine. These points may be made out 

 in the intestine of a dog, 

 or, still better, from 

 specimens of the calf's 

 intestine obtained from 

 the butcher. 



To illustrate the re- 

 lation of the mesentery 

 to the intestine, suspend 

 the arm in a sling made 

 of a handkerchief ; press 

 the two thicknesses of 

 the cloth together just 

 above the arm to repre- 

 sent the two layers of 

 the mesentery. A more 



complete representation may be made as follows : Material : 

 piece of large (one inch or more in diameter) rubber tubing, 

 eight inches long; sheet of thin white court-plaster, six inches 

 by twelve inches ; red, blue, a'nd white cord ; lay the tube 

 across the middle of the court-plaster; gum the plaster snugly 

 around the tube ; between the two adjacent layers of the 



Fig. 55. Cross Section of Abdomen. 



