HEPATIC SUGAK. 71 



the pancreas, nor the spleen. There is much less sugar in reptiles 

 than in birds and mammals, and none at all in the liver of the ray. 



Glucose exists in a fluid state in the blood, dissolved directly in 

 water. The contact of organic substances in that fluid rapidly (in 

 twenty-four hours or less) converts it, by catalysis, into lactic acid. 

 In the urine it normally combines with common salt, and thus loses 

 the taste of sugar. In the liver of the higher animals the sweetish 

 taste is owing to its presence. In some diseases no sugar at all is 

 formed in the body for a short time before death. An excess of it 

 is one of the signs of a deep general lesion. 



Origin. Normally, the grape sugar is formed in the liver, from 

 the principles of the organism itself. The parenchyma, and the 

 blood in the hepatic veins, contain it, though none exist in the food. 

 (Bernard?) But cane sugar also, entering the vena portae by endos- 

 mosis from the intestines, becomes grape sugar in the hepatic veins 

 by fixing three equivalents of water. Perhaps the sugar of milk 

 is converted in a similar manner. Glucose itself also exists in some 

 articles of food (in cooked starchy substances, grapes, &c.), and then, 

 of course, appears first in the blood of the vena porta3 ; though most 

 of such substances pass merely into the state of dextrine (C 12 H 10 O 10 ), 

 and which probably becomes glucose in the liver by assuming four 

 equivalents of water. 



The glucose actually formed in the liver (not derived from food, 

 &c.) is formed in its parenchyma, and not in the blood, 1 since in ani- 

 mals bled to death it still remains in its substance. Anything in- 

 creasing the activity of the circulation through the liver increases 

 the quantity of sugar, and vice versa. Hence, probably, the fact that 

 the condition of the nervous system modifies the amount of sugar 

 (Bernard), since this modifies the circulation. Irritation of the me- 

 dulla oblongata, at the origin of the pneumogastric nerve, was, 

 therefore, found by Bernard to increase the quantity of sugar ; and 



precisely similar shape may, however, be developed in normal urine, after standing 

 for some time at a high temperature, and sometimes even if the urine still pre- 

 serves an acid reaction. But they have generally only about one-half the diameter 

 of the yeast-cells, and are probably developed from the mucus. For an illustration 

 of the forms of vegetation in urine, see Figs. 127 and 128. 



1 Dr. C. Hanfield Jones has recently maintained that the sugar is formed by the 

 cells of the liver, while the bile is secretecf by the epithelial cells of the hepatic 

 ducts alone. Neither of these proportions, however, is probably correct. See 

 " Liver," Chap. XIII. 



