-318 DISSECTION OF THE BABBIT 



Open the duodenum opposite to the opening of the bile-duct; 

 wash out its contents ; find the aperture of the dvxit on a small 

 papilla, and insert a fine seeker or bristle into it. 



The tile-duct is most readily traced from the duodenum 

 forwards, and may with advantage be first injected withplaster 

 of Paris from a point about half an inch from the dModenmm. 



Gut through the mesentery of the small and large intestines, 

 leaving the duodenal loop and its mesentery untouched ; lay 

 out the alimentary canal on the dissecting-board, so as to show 

 the relations and proportions of its several parts. Take care 

 not to damage the splanchnic ganglia. Avoid all unnecessary 

 injwry to the blood-vessels, and ligature any that bleed. 



5. The small intestine, which is directly continuous with 



the duodenum, is about seven or eight feet in length, 

 and of uniform diameter throughout. 



a. Payer's patches are slightly thickened oval spots, 



granular in appearance, and about a third of an 

 inch in diameter, which occur at intervals along 

 the whole length of the small iatestine, on the 

 side opposite to the attachment of the mesentery. 



b. The sacculus rotundus is the dilated distal end of 



the small intestine, opening iato the side of the 

 caecum about an inch from its proximal end. Its 

 walls have the structure of Peyer's patches. 



6. The cseciun and vermiform appendix. 



The cEBCum is a large thin- walled diverticulum of 

 the alimentary canal, at the junction of the small ia- 

 testine and colon. It is about twenty inches long and 

 an inch or more in diameter, and is marked externally 

 by a spiral constriction which runs twenty to thirty 

 times round it. The small intestine opens into the 

 side of the caecum about an inch from its proximal 

 end ; a large Peyer's patch in the wall of the caecum 

 being continuous with the sacculus rotundus. 



Proximally, the cacum passes directly into the 

 colon, whUe distaUy it ends blindly in the thick- 

 waUed finger-like vermiform appendix. This latter 



