VIII. Study the duodenum ([p. 236]). Cut away the ventral walls of the duodenum far enough to expose the ampulla of Vater.
IX. Study the liver ([p. 239], and [Figs. 100] and [101]). Expose the hepatic duct of the left lateral lobe near its entrance into the lobe, and follow it so as to expose it fully. If necessary, prick it and inflate with blowpipe in order to follow it. Then expose the cystic duct and other hepatic ducts and follow them to or from the common bile-duct. Trace the latter to the duodenum. If the air does not enter any duct readily, it may be made to do so by manipulating the duct so as to break up the precipitated bile which obstructs it.
X. Study the pancreas ([p. 241], and [Fig. 102]). Expose the pancreatic duct near its entrance into the ampulla of Vater, by removing the peritoneum from the pancreas just caudad of the end of the common bile-duct, and by dissecting apart the pancreatic lobules until the duct appears. (If possible, expose also the accessory duct in the same way on the ventral side of the pancreas, two centimeters caudoventrad of the ampulla of Vater. Prick and inflate. Trace its connection with the main duct. To demonstrate its opening pass a bristle through an opening in it into the duodenum.) (The pancreatic duct may be injected, if desired.)
XI. The ventral wall of the duodenum should now be removed. Cut out a small piece, clean its mucosa with a fine brush and examine the villi with a lens. Demonstrate the coats of the duodenal wall by stripping them off with forceps.
XII. The ampulla of Vater ([p. 236]). Pass bristles through openings in the common bile-duct and pancreatic duct into the duodenum through the ampulla. Slice away the duodenal wall parallel to the bristles until the bristles are exposed.
XIII. The spleen ([p. 242], and [Fig. 102]).
XIV. Cut the mesentery from the small intestine and colon and slit them both lengthwise, but do not destroy the ileocolic valve. Wash and brush the mucous membrane clean and study the villi, solitary glands, and Peyer’s patches. Study the ileocolic valve ([Fig. 99]) and open it to study its inner surface.
DISSECTION OF THE ORGANS OF RESPIRATION.
I. The nasal cavity ([p. 243]). Review the description of the nasal cavity given under the Bones ([p. 59]). Study the cartilaginous framework that supports the external nose ([p. 243]); make a cross-section of the framework near the end of the nose and verify the description ([p. 244], and [Fig. 103]). Without injuring the larynx or tongue saw through the head in a vertical plane and a little to one side of the median line. (If desired, the brain may first be removed from the specimen and preserved for future study. For directions, see [page 462]. The removal of the brain does not injure the head for the study of the nasal cavity; the skull may be sawn lengthwise in the same way as before.) Wash out the cut surfaces before examining. Find the ventral conchæ ([p. 40]), the labyrinths of the ethmoid ([p. 43]), the inferior meatus of the nose ([p. 243]), and by bristles the lachrymal duct or canal ([p. 245]). The lachrymal duct is conveniently found by passing bristles into the openings of the lachrymal canals. One of these is to be found on the border of each eyelid, two or three millimeters from the inner angle of the eye (see [p. 410]).
Cut the œsophagus and trachea at the point where the blowpipe was inserted into the trachea. Separate the tongue, hyoid, larynx, œsophagus, and first part of the trachea from the adjacent parts and remove them.