576 



This follows from what was stated in the first communication. 

 With regard to the conversion 



we must refer to the system H,0-maltose, in which it was also 

 found that this reaction proceeds very rapidly. Hence it might be 

 said that for the sugars the hydration equilibrium seems to set in 

 very rapidly, and on this ground we assume that the hydration 

 equilibrium of /5-anhydride sets in very quickly. 



In this way we come, therefore, to the conclusion that the setting 

 in of the equilibria 



« aaq 



II and II 



must be held responsible for the mutarotation, in other words that 

 the establishment of these equilibria takes place sloivh/. 



In this view the difficulty that lies in the mutarotation theory of 

 Hudson, and is also acknowledged by himself, is entirely obviated. 

 Hudson namely assumed that we should have to do with the 

 following equilibria : 



1 2 



«anil. + HO, ^ Hydrate ^ (Sanh. + ^,0 



in which the equilibrium 1 sets in with great velocity and 2 very 

 slowly. 



On account of this view Hudson is forced to assume that for 

 maltose exactly the reverse takes place, and that it is there exactly 

 the equilibrium 2 that sets in very rapidly, and that 1 sets in very 

 slowly. 



Hudson says about this: "Why the monohydrate should change 

 instantly to the «-form for some sugars, but to the /?-foi'm for others, 

 is entirely unknown, and is a most interesting problem." 



Hudson's view was somewhat forced, as he was obliged to assume 

 for two perfectly analogous reactions, viz. hydrations of sterioisomers, 

 that one proceeds very rapidly, the other very slowly. According to 

 our view it is assumed that the reaction velocity of the said per- 

 fectly analogous conversions differs but little, whereas a great differ- 

 ence is assumed to exist between reaction velocities, one of which 

 is a hydration and the other an intra-molecular conversion. 



Mutarotation loould, therefore, not he due to a sloiv deJtydration process 

 in the sugar series, as was assumed by Hudson, but to the slow 



