204 FORMATION OF SUGAR IN THE LIVER. 



production of saccharine matter ; and that the sugar itself is pro- 

 duced by the transformation of another peculiar substance, of ante- 

 rior formation. This substance, which precedes the formation of 

 sugar, and which is itself produced in the tissue of the liver, is 

 known by the name of glycogenic matter, or glycogene. 



This glycogenic matter may be extracted from the liver in the 

 following manner. The organ is taken immediately from the body 

 of the recently killed animal, cut into small pieces, and coagulated by 

 being placed for a few minutes in boiling water. This is in order 

 to prevent the albuminous liquids of the organ from acting upon 

 the glycogenic matter and decomposing it at a medium temperature. 

 The coagulated tissue is then drained, placed in a mortar, reduced 

 to a pulp by bruising and grinding, and afterward boiled in dis- 

 tilled water for a quarter of an hour, by which the glycogenic 

 matter is extracted and held in solution by the boiling water. 



Thejiquid of decoction, which should be as concentrated as pos- 

 sible, must then be expressed, strained, and filtered, after which it 

 appears as a strongly opalescent fluid, of a slightly yellowish tinge. 

 The glycogenic matter which is held in solution may be precipi- 

 tated -by the addition to the filtered fluid of five times its volume 

 of alcohol. The precipitate, after being repeatedly washed with 

 alcohol in order to remove sugar and biliary matters, may then be 

 redissolved in distilled water. It may be precipitated from its 

 watery solution either by alcohol in excess or by crystallizable 

 acetic acid, in both of which it is entirely insoluble, and may be 

 afterward kept in the dry state for an indefinite time without losing 

 its properties. 



The glycogenic matter, obtained in this way, is regarded as 

 intermediate in its nature and properties between hydrated starch 

 and dextrine. Its ultimate composition, according to M. Pelouze, 1 



is as follows : 



C, 2 H 12 I2 . 



When brought into contact with iodine, it produces a coloration 

 varying from violet to a deep, clear, maroon red. It does not 

 reduce the salts of copper in Trommer's test, nor does it ferment 

 when placed in contact with yeast at the proper temperature. It 

 does not, therefore, of itself contain sugar. It may easily be con- 

 verted into sugar, however, by contact with any of the animal 

 ferments, as, for example, those contained in the saliva, or in the 



1 Journal de Physiologie, Paris, 1858, p. 552. 



