GLYCOGEN AND GLUCOSE IN THE LIVER. 237 



parts per thousand. These variations appear to depend upon individual 

 differences in the animals employed for experiment ; in the same man- 

 ner as other ingredients of the tissues and fluids are founcl to vary, 

 within physiological limits, in different individuals. 



As sugar is found, under some circumstances, in minute quantity in 

 the blood of the general circulation, there might be room for doubt 

 whether the glucose, present in the liver at the moment of death, be not 

 due to the arterial blood with which the organ is supplied, rather than 

 an ingredient of the hepatic tissue. This, however, is not the case, as 

 is shown by examining, at the same time with the liver or immediately 

 afterward, some other abdominal organ equally well supplied with arte- 

 rial blood. In the experiments above described, the spleen in three 

 cases was taken out within ten minutes after the excision of the 

 liver, treated in the same manner by the alcohol process, and examined 

 for glucose with the following result: 



PROPORTION OF GLUCOSE PER THOUSAND PARTS. 

 At the end of In the 



Exp. No. 14. | 3 seconds Liver . . 



( 10 minutes ; Spleen . 



Exp. No. I 9 .l 5seconds ^ er 



1 10 minutes '. Spleen . . 0. 



Exp.No.20.{ 4 seconds ^y er 2 ' 675 



(30 minutes .... Spleen . . 0. 



It is evident, accordingly, that the liver sugar does not belong to the 

 arterial blood with which the organ is supplied, but is a normal ingre- 

 dient of the hepatic tissue. 



The sugar formed in tho liver is similar in most of its properties to 

 the glucose derived from other sources. Its solution readily reduces 

 the salts of copper in Trommer's or Fehling's test, and is colored brown 

 when boiled with a solution of caustic alkali. It rapidly enters into 

 fermentation if mixed with yeast and kept at a temperature of from 21 

 to 38 (700 to 1000 F.). It is distinguished from other varieties of sugar, 

 according to Bernard, 1 by the readiness with which it becomes decom- 

 posed in the blood since cane sugar, if injected into the circulation of 

 a living animal, passes through the system without sensible decomposi- 

 tion, and is discharged unchanged with the urine; sugar of milk, and 

 glucose prepared artificially from starch, if injected in moderate quan- 

 tity, are decomposed in the blood, but if introduced in greater abund- 

 ance, make their appearance also in the urine ; while a solution of liver- 

 sugar, though injected in much larger quantity than either of the others, 

 may disappear altogether in the circulation, without passing off by the 

 kidneys. 



Absorption and final Disappearance of the Liver-sugar. The glu- 

 cose produced in the liver by transformation of the glycogen does not 



1 Lemons de Physiologic Experimental. Paris, 1855, p. 213. 



