246 QUANTITATIVE ANALYSIS. 



in order to wash out the last traces of the glycogen, and add 

 it to the 500-cc. flask. Repeat this rinsing until the 500-cc. 

 flask is almost but not quite filled to the mark. Finally 

 allow a few cubic centimeters of the fluid to run into a test- 

 tube and add several cubic centimeters of 96 per cent, alco- 

 hol. No turbidity should result. Then close the 500-cc. 

 flask with a rubber stopper and shake the mixture thoroughly. 

 It contains approximately 2.2 per cent, hydrochloric acid. 

 These directions must be modified : 



1. When such a small quantity of glycogen is present that 

 an exact analysis cannot be carried out. In this case we 

 precipitate the glycogen with an equal volume of alcohol, 

 not from 100 cc. of the filtered meat solution, but from 200 or 

 300 cc., and proceed as directed above. 



2. When the glycogen is to be estimated in a very small 

 organ, e.g., in the liver of a chicken. In this case weigh off 

 10 g. of the finely chopped liver and put it into a small flask 

 with 10 cc. of 60 per cent, potash solution. After heating 

 for two hours in the water-bath, cool and fill up to 40 cc. 

 with water. Filter through glass wool and use 25 to 30 cc. 

 for precipitation with an equal volume of 96 per cent, alcohol. 

 Filter through a small Swedish filter and proceed as directed 

 above. 



The solution of the glycogen on the filter must be made 

 so that not more than 100 cc. of the filtrate with 2.2 per cent, 

 of hydrochloric acid is obtained in a 100-cc. flask. 



Determination of the Glycogen by Conversion into Glucose. 



The flask containing the glycogen solution is placed in a 

 boiling-water-bath and closed with a rubber cork as soon as 

 the expansion of the liquid caused by the heat has ceased. 

 After heating for three hours, remove the flask from the 

 bath, let it cool, and fill up to the mark with water. Then 

 filter the sugar solution through a dry Swedish filter into a 



