GLYCOGEN AND GLUCOSE IN THE LIVER. 233 



and in most kinds of fish. ' It was only in two species of fish, namely, the 

 eel and the ray (Muraena anguilla and Eaia batis), that he sometimes 

 failed to discover it ; but the failure in these instances was apparently 

 owing to the commencing putrescence of the tissue, by which the sugar 

 had probably been destroyed. In the fresh liver of the human subject, 

 examined after death from accidental violence, sugar was found to be 

 present in the proportion of 1.10 to 2.14 per cent, of the entire weight 

 of the organ. 



The following list shows the average percentage of sugar present in 

 the healthy liver of man and different species of animals, according to 

 the examinations of Bernard : 



PERCENTAGE OF GLUCOSE IN THE LIVER. 



In man . . . 1.68 In ox . . . . 2.30 



" monkey . . . 2.15 " horse . . . 4.08 



dog . . . . 1.69 " goat .... 3.89 



" cat . . . . 1-94 " birds .... 1.49 



" rabbit . . . 1.94 " reptiles . . . 1.04 



" sheep . . . 2.00 " fish . . . . 1.45 



The glucose thus found in the liver originates by transformation of 

 the glycogen of the hepatic tissue. As glycogen diminishes in quantity 

 or disappears altogether by continued fasting, and is again produced 

 from the ingestion of animal food, the glucose which is derived from it 

 exhibits similar fluctuations. In the carnivorous animals, sugar is pre- 

 sent in the liver, although no carbohydrates have been given with the 

 food for an indefinite time. Bernard kept a dog under observation 

 for three months upon an exclusive diet of boiled calves' heads, and 

 another for eight months upon scalded tripe. At the end of that 

 time the liver in each case contained the usual quantity of glucose. 

 We have also found that in the dog, after an exclusive diet for eight 

 days of the fresh meat of the bullock's heart, the liver contains both 

 glycogen and sugar, while neither of these substances exists in the 

 blood of the portal vein. The diminution of glucose by fasting, and its 

 reappearance under the influence of animal food, were shown by Ber- 

 nard in the following way : Nine rats, taken in the sewers beneath the 

 College of France, were used for experiment. Three of them were at 

 once killed and their livers found to be highly saccharine. The remainder 

 were then kept without food for four days. At the end of that time 

 three of them were killed, and their livers, upon examination, found to 

 be nearly destitute of sugar, only slight traces being discovered, too 

 small for quantitative determination. The glucose which existed, ac-' 

 cordingly, in the livers of these animals at the time of their capture, 

 had disappeared during their four days' period of fast. The remaining 

 three were then supplied with a meal of raw beef, and when killed, six 

 hours afterward, their livers contained an abundance of sugar. 



The most distinct proof that the saccharine matter of the liver origi- 

 16 



