GLYCOGEN AND GLUCOSE IN THE LIVER. 241 



of it may be eliminated, so that it is no longer to be found as an ingre- 

 dient of the excretions. 



There are a variety of circumstances which may so increase the pro- 

 portion of glucose in the blood as to cause a saccharine condition of the 

 urine. 



I. One of these causes is an unusually abundant and rapid absorption 

 of sugar from the intestine. The sugar taken in with the food, or pro- 

 duced in the intestine by the transformation of starch, is usually changed 

 into glycogen by the hepatic tissue, and is afterward only slowly recon- 

 verted into glucose and discharged under this form into the blood. But 

 where a very large quantity of sugar is suddenly absorbed by the blood- 

 vessels of the intestine and at once carried by the portal vein to the 

 liver, the tissue of the organ is not capable of immediately converting 

 the whole of it into glycogen. Thus a portion of the sugar taken up 

 in this way passes through the hepatic circulation unchanged, and, reach- 

 ing the general circulation in unusual quantity, is accordingly discharged 

 with the urine. Yon Becker observed that when concentrated solutions 

 of glucose are introduced in abundance into the intestinal canal of the 

 rabbit, it may appear subsequently in the urine. Bernard has also found 

 that, in the rabbit after one or two days' fasting, if sugar in large amount 

 be injected into the stomach, the urine becomes diabetic; and that the 

 same result may follow, if the animal, in a similar fasting condition, be 

 made to eat a considerable quantity of carrots, which are highly saccha- 

 rine. The same thing has been observed by Bernard in the human sub- 

 ject, in consequence of taking a large supply of sugar in solution when 

 the stomach has been empty for several hours. This result is produced, 

 however, only when a much greater abundance of sugar is present in 

 the intestine than occurs in ordinary digestion, and depends upon the 

 excessive quantity absorbed within a given time. 



II. A diabetic condition may also be induced by anything which 

 hastens the circulation of blood through the liver, or increases its supply 

 of blood. Many observers have met with this result, as produced by a 

 variety of causes. Bernard has found that in dogs the blood of the 

 venous system generally may present traces of glucose after the abdo- 

 men of the animal has been subjected to pressure or manipulation over 

 the region of the liver, and after any continued struggles or convulsive 

 muscular action, by which the abdominal organs are forcibly compressed 

 In the same animal, according to the experiments of Harley, the injec- 

 tion of weak solutions of ammonia or of ether into the portal vein may 

 be followed by a saccharine condition of the urine. This condition has 

 also been seen in the human subject after a bruise received upon the 

 right hypochondriac region. The resistance of an animal to the inhala- 

 tion of ether and the subsequent muscular relaxation, general paralysis 

 from a fracture of the skull with cerebral hemorrhage, and the action of 

 woorara, or the South American arrow-poison, which also causes complete 

 muscular paralysis, are all known to be. sometimes followed by the ap- 



