PANCREATIC DIGESTION. 47 



V. Pancreatic Digestion. Amylolytic Ferments. G'ycogen. 



1. Pancreatic Digestion. 



a. Introduce five c.c. of one per cent, solution of sodium carbonate, to which 

 a couple of drops of glycerine extract of pancreas have been added, into each 

 of two test-tubes. Boil one of them and allow it to cool. Add some boiled 

 fibrin to each, and place them both in the water-bath at 35 C. Compare 

 the changes produced with those observed in peptic digestion ( iv, 3, c). 



b. Examine the liquid product of a pancreatic digestion, previously pre- 

 pared by digesting albumin as in a. It is alkaline, and may have a charac- 

 teristic and offensive odour. 



c. Boil some of this liquid after acidulating slightly. Albumin is coa- 

 gulated. 



d. Colour another portion with litmus, and neutralize carefully ( iii, 5) ; 

 alkali-albumin is precipitated. 



e. In a liquid obtained by concentrating the product above referred to, after 

 having separated the greater part of the proteids contained in it, test for 

 Tyrosin by adding Millon's reagent and boiling. The presence of Tyrosin 

 is indicated by the reddish colour assumed by the liquid. 



f. The liquid contains LeilCin in a crystalline form. 



2. Peptones. A solution obtained either by pancreatic or peptic 

 digestion can be used. 



a. The solution yields no precipitate either by boiling or by neutralization. 



b. When treated as in iv, I, e, it gives a red instead of a violet colour. 

 The liquid product of the slow putrefaction of proteids resembles in 



most respects that of pancreatic digestion. To the latter, the presence of 

 septic organisms is not essential. 



3- Amylolytic Ferments. Prepare some starch solution and 

 ascertain that it contains no dextrose, i, 2 and 8. To another portion add 

 saliva, and place the tube containing the mixture in a water-bath at from 

 35 to 38 C. After a short time, the product will be found to contain 

 dextrose. 



4- Glycogen. 



a. To an extract of liver (prepared by extracting the perfectly fresh organ 

 with boiling water after washing) add a solution of iodine in potassic iodide. 

 The liquid assumes a red colour identical with that yielded under similar 

 circumstances by dextrine (see i, 5). 



b. On treating a slice of washed liver, hardened in alcohol, with iodine 

 solution, a similar colour is seen. 



c. Repeat 3, substituting extract of liver for starch .paste, using the same 

 precautions. 



1. Observe colour and reaction. The bile of carnivora is brownish-red 

 that of herbivora green. Neutralize and boil in a test-tube. Bile does not 

 contain albumin. 



2. Acidify bile with acetic acid ; mucin is precipitated 



