230 PRODUCTION OF 



in the bodies of maggots during the course of their development, 

 although neither the eggs from which they are hatched, nor the putrefy- 

 ing meat upon which they feed, contain any appreciable traces of this 

 substance. 



Glycogen is produced, however, in especial abundance in the liver, 

 after the ingestion of starchy and saccharine food. Bernard 1 found the 

 decoction of the liver tissue in the dog, after feeding for two days with 

 bread and starch paste, very turbid and milky in appearance. Subse- 

 quent experiments by the same observer 2 have shown that a starchy 

 diet augments notably the quantity of glycogen existing in the liver. 

 This fact was first demonstrated in a special manner by the observations 

 of Pavy, 3 who, by comparative experiments upon dogs fed with animal 

 and vegetable food, found that the influence of the latter was to increase 

 very decidedly the weight of the whole liver, and also the pencentage 

 of glycogen which it contained. The same effect was produced by a 

 diet of animal food with sugar in addition. The following table gives 

 the average results of three series of observations by Pavy : 



AVERAGE PRODUCTION OF GLYCOGEN, IN DOGS, UNDER DIET OF ANIMAL AND 

 VEGETABLE FOOD. 



Diet for "Weight of liver, Glycogen in the 



several days in percentage of fresh liver, 



previously. bodily weight. per cent. 



Tripe 3.03 7.19 



Tripe and sugar . . . 6.42 14.50 



Meal, bread, potatoes . . 6.06 17.23 



Experiments on the rabbit also showed that in this animal both the 

 weight of the liver and its percentage in glycogen are much diminished 

 by several days' fasting, but are maintained at the maximum standard, 

 for a time at least, by a diet consisting exclusively of the carbohydrates. 

 The average results were as follows : 



AVERAGE PRODUCTION OF GLYCOGEN IN RABBITS, TN THE FASTING CONDITION AND 

 WHEN FED ON CARBOHYDRATES. 



Diet for Absolute weight Glycogen in the 



three days of liver fresh liver 



previously. (grammes). (per cent.). 



No food 34.02 1.35 



Starch and sugar . . . 73.71 16.15 



The quantity of glycogen found in the liver by Pavy is considerably 

 greater than that obtained by subsequent observers under similar cir- 

 cumstances, and is attributed to his having employed an imperfect 

 method of purification ; but the principal fact of the increase of glycogen 

 under the use of the carbohydrates has been confirmed by several other 



1 LeQons de Physiologic Experimentale. Paris, 1855, p. 159. 



2 Revue des Sciences Medicales. Paris, 1874, torn. iii. p. 34. 



3 On the Nature and Treatment of Diabetes. London, 1862. 



