122 



EXERCISE XX 



PANCREATIC SECRETION AND THE PREPARATION AND ACTION OF 



SECRETIN ; BLADDER-BILE. 



I. See that the decerebrate preparation provided is in good condition 

 on the warm table, and that if necessary it is ventilated by the pump. 



II. Have ready, in addition to your usual operation instruments, the 

 following : (i) small packing-needle with string for ligatures for intestine ; 

 (ii) pestle and mortar and some fine sand, and 250 c.c. -IS/^ HCl ; also an 

 evaporating dish on tripod and wire gauze over an ordinary Bunsen burner ; 

 (iii) a glass rod and small bottle containing 2/„ NaOH solution, a glass 

 funnel and pleated filter-papers to fit ; (iv) litmus paper ; (v) a glass 

 cannula with nozzle about 1 mm. diam. and shank about 7 cm. long ; 

 this is for the pancreatic duct ; (vi) a shorter glass cannula, with nozzle 

 about 2 mm. diam., for the common bile duct. 



Obs, 91. III. Operation. Place preparation supine with limbs extended by clip- 



Preparation of weights. Make in the mid-ventral line an incision through the abdominal 

 wall from the root of the xiphoid cartilage backwards two-thirds of 

 the way to symphysis pubis, taking care not to wound the abdominal con- 

 tents. Note the small intestine exposed at the upper part of the incision ; 

 it is jejunum ; follow it backward towards the posterior abdominal wall 

 where it joins duodenum. Carefully lift duodenum and turn it towards 

 preparation's left side. Pancreas will be seen to be attached to the 

 mesenteric border of duodenum (text-fig. 42). Follow the adherent borders 

 of the two in a direction away from stomach ; at a certain distance the 

 pancreas ends and leaves the gut free from it. Close beyond that point 

 pass a double-strung ligature round the gut, gently squeeze empty the gut 

 between the ligatures, and tie the latter separately and about 1 cm. apart. 

 Follow the gut farther downward for a length of about 30 cm., and there 

 pass a double ligature as before and tie separately about 1 cm. apart. 

 Drawing on the ligated loop, make out the mesenteric vessels supplying 

 it, gather them together in the root of the mesentery, ligate them. Sever 



secretin. 



