The Liver and Pancreas. 107 



The use of glycogen is to supply muscular energy and 

 animal heat. During work it diminishes in the muscles, 

 and during rest it is stored up. 



Foster warns us against regarding the glycogen of muscle 

 as of any value in the production of muscular energy until 

 it has actually become muscle. As he expresses it, ' It 

 cannot be fired off as raw glycogen, or even as dextrose, in 

 the interstices of the muscular fibre ' ; it must first become 

 muscle. 



The source of glycogen is a disputed point: carbo-hydrates, 

 no doubt, contribute largely to its production ; but there is 

 reason to believe that proteids also assist in its formation. 

 The majority of observers agree that fat takes no part in 

 the production of glycogen. 



The hepatic blood contains, roughly, twice as much sugar 

 as the portal (Seegen, quoted by Halliburton). Lehmann 

 states that in starving horses he found no sugar in the 

 portal vein, although it was always to be detected in the 

 hepatic vein. 



When the liver is removed from the body the glycogen 

 diminishes and the sugar increases. No ferment theory, 

 according to Halliburton, is required to explain this con- 

 version, as a diastatic ferment can be obtained from all 

 living proteids. By the administration of glycerin the 

 post-mortem conversion of glycogen into sugar may be 

 prevented (Ransom).* The same observer discovered that 

 the administration of glycerin also prevented the diabetes 

 of rabbits which follows an injury of the medulla, and he 

 concludes that glycerin inhibits the formation of sugar in 

 the liver-cells. 



If glycocin be injected into the blood, according to 

 some observers the formation of glycogen in the liver 

 as well as of urea is increased. 



Bernard discovered that by puncturing the floor of the 

 fourth ventricle sugar appeared in the urine. The explana- 

 tion of this may be that it is due to paralysis of the blood- 

 vessels of the liver, the nerves of which originate in the 



* Quoted by Halliburton. 



