CHAPTER XII. 

 EXAMINATION OF THE LIVER. 



I. Preparation and Reactions of Glycogen. 

 II. Detection of Sugar. 

 III. Preparation of the Xanthine Bases of the Liver. 



I. PREPARATION OF GLYCOGEN. 



Introduce, by means of a tube, into the stomach of a well- 

 fed rabbit, on the day previous to killing it, as well as five to 

 six hours before death, 10 to 15 g. of glucose or cane-sugar 

 dissolved in water. After killing the rabbit remove the liver. 

 Reserve about 10 g. of this for the experiment below ^detec- 

 tion of sugar), and chop up the rest into very small pieces. 

 Then heat to vigorous boiling with ten times its weight of 

 water, adding a trace of acetic acid in order to facilitate the 

 precipitation of the proteids. Filter the extract, which shows 

 a marked opalescence, through muslin, press the residue 

 thoroughly, grind it in a mortar, and boil again with water, 

 filter, and press out the residue as before. Evaporate the 

 united extracts to about 100 to 150 cc., acidify with hydro- 

 chloric acid, and add Briicke's solution * (potassium mercuric 

 iodide), then alternately a few drops of hydrochloric acid and 

 Briicke's solution until the precipitation is complete. The 

 addition of the Briicke's solution is for the purpose of pre- 



1 Made as follows: To a hot 5 to 10 per cent, solution of potassium 

 iodide add with constant stirring mercuric iodide until a portion remains 

 undissolved, let cool, and then filter. 



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