MAl^tTAL OF OATTLE-FEEDING. 89 



Tlie cause of tlie comparatively small quantity of sugar 

 found in tlie body, notwitlistanding the large amounts 

 taken into the blood, lies partly in the fact that the pro- 

 cess of resoi-ption is a gradual one, extending over a con- 

 siderable time, the sugar, after it passes into the cireuk- 

 tion, being oxidized with comparative rapidity, and partly, 

 as it v^ould appear, in the conversion of the resorbed sugar 

 into an insoluble form by the liver. 



Glyeogen. — The liver, as long as it is in a normal state, 

 contains a substance belonging to the carbhydrate group, 

 and known as glycogen^ in quantities varying according to 

 the diet of the animal- 

 It may be extracted from the liver by hot water, and 

 when purified forms a white, meal-like, amorphous pow- 

 der, tastele^ and odorless. In cold water it swells up, and 

 on warming dissolves to an opalescent fluid. It is insolu- 

 ble in alcohol and ether, and is colored dark-red by iodine. 

 All those agents which convert starch and dextrine into 

 sugar produce the same eifect upon glycogen. It rotates 

 the plane of polarized light strongly to the right, but does 

 not reduce alkaline copper solution. It will thus be seen 

 that it stands intermediate between starch and dextrine. 

 Its composition is the same as that of starch. 



G-Iyeogenio Ftinetlon of the Liver, — If the dead 

 liver, after removal from the body, be washed out by 

 water injected through the portal vein till all sugar is re- 

 moved, and if then, after standing for a time, the washing 

 be renewed, the first portions of water that pass contain 

 sugar. The same process may be repeated several* times, 

 " If the liver of any animal be kept for a considerable 

 time before cooking, the amount of sugar which accumu- 

 lates in its substance is so large as to be easily detected by 

 the taste. The liver is deoldedly sweetJ^-^-^S, Le Gonte.) 



