PANCREAS AND SECRETIN 



123 



the two ends of the intestinal loop with a scissor-cut at each end between 

 the double ligature. Exsect the loop, cutting its mesentery distal of 

 course to the ligated blood-vessels. Close the abdominal wound. 



Text-fig. 42. Pancreatic-duodenal junction (cat) viewed from right side, 

 duodenum being drawn over towards preparation's left by clip-weights. L, cystic 

 lobe of liver ; St, stomach ; Py, pylorus; JD, duodenum; J, jejunum; Pa, pancreas ; 

 cBd, common bile duct ; G, gall-bladder ; Vp, portal vein ; Pd, indicates by arrow 

 the place where the main pancreatic duct usually enters duodenum ; hook- 

 weights retract the right edge of abdominal opening. 



IV. Wash the exsected loop through under the tap. Slit it open 

 along its whole length. Scrape oif thoroughly, with a long-bladed scalpel, 

 the mucosa, collecting the scrapings on a clean glass plate. Mix with them 

 an equal volume of sand which has been moistened with a few drops of 

 •15/„ HCl. Transfer this paste to the evaporating dish, and add 150 c.c. 

 •15/„ HCl. Raise the mixture to boiling over the flame. When actively 

 boiling add 2/„ NaOH drop by drop until mixture, as tested by litmus, 

 is almost neutral, i. e. very faintly acid. On removing the flame the coa- 

 gulated proteins will sink, leaving a clear supernatant liquor. Filter this 

 through filter-paper as quickly as practicable. The filtrate contains 

 * secretin '. 



V. Prepare left external jugular vein (see exerc. VI, J VII) for insertion 

 of cannula, but do not insert that yet. Leave the wound covered with a 

 moist swab. 



R 2 



