404 PROCESSES INFERRED FROM DIRECT OBSERVATION 



the fats is highly specific and the oxidation of other and even much 

 more difficultly oxidizable substances may be normal; thus Lactic Acid, 

 Mannitol and even Inosite or Benzene are oxidized just as well by the 

 diabetic as by the normal individual. Even a very slight degree of 

 oxidation of glucose itself suffices to enable the tissues to overcome the 

 obstacle. Thus gluconic acid, glucuronic acid, saccharic acid and mucic 

 acid are all readily oxidized by a diabetic. The relationship of these 

 substances to glucos*e may be seen from the following formulae 



CHO COOH CHO COOH COOH 



ill!! 



HCOH HCOH HCOH HCOH HCOH 



I ' I I ! I 



HOCH HOCH HOCH HOCH HOCH 



I I I I I 



HCOH HCOH HCOH HCOH HOCH 



I I I I I 



HCOH HCOH HCOH HCOH HCOH 



r i i i i 



CH 2 OH CH 2 OH COOH COOH COOH 



Glucose. Gluconic acid. Glucuronic Saccharic Mucic acid. 



acid. acid. 



Even more surprising is the fact that sugars other than glucose may 

 be very much better utilized by a diabetic than glucose itself. Cane- 

 sugar is badly tolerated, as might be expected from the fact that it 

 yields glucose on hydrolysis. For the same reason Maltose, which 

 yields two molecules of glucose when hydrolyzed, is even less well 

 tolerated by diabetics than cane-sugar. Lactose is very badly tolerated 

 probably because it gives rise, on hydrolysis, not only to glucose but 

 also to Galactose which is very poorly assimilated by diabetics. Levu- 

 lose, on the contrary is comparatively well assimilated. In many 

 cases it is possible to administer levulose to diabetics without untoward 

 symptoms when similar quantities of glucose would precipitate a pro- 

 found glycosuria. Depancreatized dogs will store up glycogen on a 

 levulose diet when they cannot do so on a diet containing equal quanti- 

 ties of glucose. For this reason, since levulose is somewhat expensive, 

 it has been proposed to administer Inulin to diabetics. Inulin is a 

 polysaccharide of levulose which occurs in the tubers of dahlias, the 

 tuberous artichoke and the sweet potato. It is, however, indigestible 

 by any of the alimentary juices and simply increases the bulk of the 

 feces and provides a culture-medium for intestinal bacteria. The 

 bacteria in the lower intestine certainly attack inulin and the products 

 of their activity may be absorbed or utilized, but these products are 

 not of a carbohydrate nature, for if inulin be administered to an animal 

 with phloridzin glycosuria, no increase of sugar-output is observed. 

 Inulin is therefore of little if any value to a diabetic. 



Now it is a very significant fact that when levulose is tolerated by a 

 depancreatized animal, it is converted into glycogen in the liver. 

 This would point, seemingly, to a failure of the liver to convert glucose 

 into glycogen in diabetics, although it is well able to store the glycogen 



