FORMATION OF SUGAR IN THE LIVER. 203 



appear altogether in the circulation, without passing off by the 

 kidneys. 



This substance is therefore a sugar of animal origin, similar in 

 its properties to other varieties of saccharine matter, derived from 

 different sources. 



The sugar of the liver is not produced in the blood by a direct 

 decomposition of the elements of the circulating fluid in the vessels 

 of the organ, but takes its origin in the solid substance of the hepatic 

 tissue, as a natural ingredient of its organic texture. The blood 

 which may be pressed out from a liver recently extracted from the 

 body, it is true, contains sugar ; but this sugar it has absorbed from 

 the tissue of the organ in which it circulates. This is demonstrated 

 by the singular fact that the fresh liver of a recently killed animal, 

 though it may be entirely drained of blood and of the sugar which 

 it contained at the moment of death, will still continue for a certain 

 time to produce a saccharine substance. If such a liver be injected 

 with water by the portal vein, and all the blood contained in its 

 vessels washed out by the stream, the water which escapes by the 

 hepatic vein will still be found to contain sugar. M. Bernard has 

 found 1 that if all the sugar contained in a fresh liver be extracted in 

 this manner by a prolonged watery injection, so that neither the 

 water which escapes by the hepatic vein, nor the substance of the 

 liver itself, contain any further traces of sugar, and if the organ be 

 then laid aside for twenty-four hours, both the tissue of the liver and 

 the fluid which exudes from it will be found at the end of that time 

 to have again become highly saccharine. The sugar, therefore, is 

 evidently not produced in the blood circulating through the liver, 

 but in the substance of the organ itself. Once having originated 

 in the hepatic tissue, it is absorbed thence by the blood, and trans- 

 ported by the circulation, as we shall hereafter show, to other parts 

 of the body. 



The sugar which thus originates in the tissue of the liver, is pro- 

 duced by a mutual decomposition and transformation of various 

 other ingredients of the hepatic substance ; these chemical changes 

 being a part of the nutritive process by which the tissue of the 

 organ is constantly sustained and nourished. There is probably a 

 series of several different transformations which take place in this 

 manner, the details of which are not yet known to us. It has been 

 discovered, however, that one change at least precedes the final 



1 Gazette Hebdomadaire, Paris, Oct. 5, 1855. 



