228 GLYCOGEN 



number of other hexoses, as the mannoses, sorbose and chi- 

 tose, to form glycogen seems, to say the least, questionable. 

 Glycogen formation from the first-named types of sugar was 

 proved even as early as C. v. Voit and his school. They are 

 by no means equally capable, galactose normally being fixed 

 in the form of the reserve carbohydrate with more difficulty 

 than are glucose and laevulose. A fasting, healthy human 

 being can take up as much as 100. to 150. grams of glucose 

 from the stomach at one time without excreting sugar in the 

 urine; the " limit of assimilation " for galactose is very 

 much lower, about 30. to 40. grams. Galactose is assimilated 

 with especial difficulty by carnivora; canine urine showing 

 reducing power even when the animal is merely kept on a 

 milk diet, as observed many years ago by F. Hofmeister. 

 When Grube perfused the living excised turtle-liver with 

 Binger's solution to which was added sugar of different 

 kinds, he noted that large amounts of glycogen were pro- 

 duced from glucose and from fruit sugar but far less from 

 galactose. It is a strange thing that galactose is better 

 assimilated by the human diabetic, according to F. v. Voit, 

 than is glucose, the diabetic patient having lost the capacity 

 of utilizing the latter. The same is true of laevulose, as shown 

 by Minkowski in case of pancreatic diabetes and by L. 

 Pollak 21 in case of adrenin diabetes. From a further in- 

 vestigation (in the Vienna Pharmacological Institute) 22 

 it would seem that in phosphorus-poisoning the liver, 

 although it has lost its power of forming glycogen from 

 glucose, is still able to freely construct glycogen when 

 laevulose is exhibited. It is impossible thus far to explain 

 this remarkable peculiarity. It might be conjectured that 

 the glycogens formed from laevulose or galactose are in some 

 way different from the form of glycogen from dextrose; 

 that perhaps the glycogen from laevulose would hydrolyse, 



21 L. Pollak (Pharmacol. Instit., Vienna), Arch. f. exper. Pathol., 61, 149, 

 1909. 



22 E. Neubauer (Pharmacol. Instit., Vienna), Arch. f. exper. Pathol., 61, 

 174, 1909. 



