328 Intelligence and Miscellaneous Articles. 



of sugar from the liver, because the digestion of another meal com- 

 mences before the quantity of sacchaiine material already formed iet 

 exhausted. If, however, we subject animals to forced abstinence, 

 the sugar after a time completely disappears, and the liver exhibits 

 no more trace of it than any other organ of the body. 



Accordingly, as it is a fact that in all animals during digestion the 

 hepatic tissue and the blood which issues from it constantly contain 

 sugar, so it is equally true inversely, that in all animals subjected 

 to abstinence prolonged sufficiently, the liver and hepatic blood are 

 entirely deprived of saccharine matter, which, however, immediately 

 reappears as soon as digestion and nutrition resume their activity. 



The duration of abstinence required for the complete elimination 

 of sugar from the liver presents many variations according to species, 

 age, health, &c. I shall merely state that in birds the disappearance 

 is very rapid, occurring at the end of two or three days ; while in 

 dogs it is complete only at the end of seven or eight days of starva- 

 tion. In cold-blooded animals a much longer time is required. 



We shall afterwards observe, that in cases where the function of 

 digestion is disturbed or disordered, one of the first results is the 

 disappearance of sugar from the liver and from the blood of the he- 

 patic veins. Hence the presence of saccharine matter there must be 

 regarded in animals in their ordinary condition as the indication of 

 the normal performance of digestion. 



2nd. Sugar is produced in the liver independently of the nature of 

 the food. 



The experiments above cited might serve to show that the sugar 

 is formed in animals without the intervention of saccharine or amy- 

 laceous principles in the food, since the presence of sugar was de- 

 tected in carnivora, as well as in omnivora and herbivora in the 

 animal series. However, as the fact of the production of sugar in 

 the liver is still new, and has most important bearings on physiology, 

 I shall support the above proposition on the evidence of special and 

 direct experiments. 



To demonstrate that the saccharine matter originates in the liver, 

 and is not introduced with the food, animals such as dogs, cats, or 

 even rabbits, must be subjected to a diet exclusively animal, and 

 containing no substance which can by the process of digestion give 

 rise to saccharine principles in the alimentary canal. Thus I have 

 fed dogs during three, four,, five, and even eight months exclusively 

 on flesh ; and on examination at the end of that period, I have con- 

 stantly found that, while the intestines and blood of the vena portse 

 at its entrance into the liver contained no sugar, the blood of the 

 hepatic veins was always abundantly charged with it. But an expe- 

 riment less prolonged proves the production of sugar in the liver. 

 In fact, as before stated, the dog's liver may be completely deprived 

 of sugar by an abstinence of seven or eight days' duration. If at 

 the end of that period the animal be fed on flesh only, the sugar will 

 nevertheless reappear in the liver as soon as the process of digestion 

 determines increased activity in the circulation of the organ. When, 

 therefore, in animals fed exclusively upon flesh, it is constantly as- 

 certained that the blood brought to the liver by the vena portse con- 



