GLYCOGEN IN THE LIVER. 69 



acid in a flask ; neutralise with caustic soda, and test with 

 Fehling's solution for sugar. 



(e.) To another portion add plumbic acetate = a precipitate 

 (unlike dextrin). 



(f.) To another portion add plumbic acetate and ammonia 

 = a precipitate (like dextrin). 



5. Test the watery extract of the second half of the liver (d). 



(a.) It will perhaps give no glycogen reaction, or only a 

 slight one. 



(b.) It contains much reducing sugar. 



6. Extract of a Dead Liver. 



(a.) Mince a piece of liver from an animal (e.g., an ox) 

 which has been dead for twenty-four hours. Place the 

 finely-divided liver in water or in a saturated solution of 

 sodic sulphate, and boil to make a watery extract. Filter, 

 and observe the nitrate ; it is clear and yellowish in tint, 

 but not opalescent. 



(b.) Test its reaction = acid. 



(c.) Test with iodine after neutralisation with sodic car- 

 bonate and nitration = no glycogen. 



(d.) Test for grape-sugar = much sugar. 

 After death the glycogen is rapidly transformed into grape- 



LESSON XL 

 MILK, FLOUR, AND BREAD. 



1. Milk. Use fresh cow's milk. 



(a.) Examine a drop of milk under the microscope, noting 



