( 13) 



towards c'anesno:ar '), but not the reverse. This is in liarniony with 

 the ra(UatioJi theory. Maltose, like eanesiigar, is an «-glncoside. The 

 connecting' point of the laevnlose in fhe cancsugar nioiecnle with the 

 rf-gliicose is the C of the carhoiiyl groiij» of the laexulose. In maltose 

 the ff-glncose is attached (o the (Tl, of the otherwise nnconibined 

 molecule of glucose. Canesugar is also much more I'eadily inverted hv 

 acids than maltose. Both radiating «-glucose and laevnlose ([)rol)al)ly 

 also radiating ji-glucose ')) are liable to invert canesugar. Maltose 

 is Old}' converted by active «-glucose, bid as may be expected from 

 its behaviour towards acids and its constitutional formula it recpures 

 a moi"e powerful i-adiation than canesugar. If, therefore, yeast-extract 

 has been ^veakened by ele\'ation of temperature or by precipitation, 

 its power of inverting maltose may liave been lost or nnu-h diminished, 

 although canesugar is still fairly rapidly inverted. 



The preparation of a yeast-extract with a powerful inverting action 

 on maltose proved to me no more difticult than when inversion of 

 canesugar was intended. The al)ove-described yeast, derived from a 

 canesugar solution, and which had been actually heated at lOO'^ for 

 half an hour, yielded after a year and a half an extract which 

 readily inverted maltose. In this case, 1 used, of course, by preference 

 a yeast whicii had been mixed with "kieselguhr" and dried at a 

 low temperature. On extracting the dried mixture, the solution never 

 contains zymase as experiment repeatedly showed. 



Figures 5, 6, 7, 8 and 9 now 

 clearly show the phenomena of 

 equilibrium. If «-glucose in solution 

 were stable, only 157» of the 

 total might be inxerted by yeast- 

 extract in a lO"/,, maltose solution. 

 The fact that maltose is decom- 

 posed by yeast-extract so much 

 slower than canesugar is partly 

 <lue to the ciri-umstance that the 

 point of (MpMJibi'ium is reached 

 so much earlier. The furthei- decomposition then again merely keeps 

 pace with the transformation of «-glucose into ,i-glucose. 



10 15 



20 



25 



1) FoTTEviN, Annales lust. Pastüuk 1908. p. 31. 



~) Separate expefimeiits showed lIuU glucose, previously heated and therefore in 

 the ^-form, and glucose, dissolved ininiedialely befoie adding the enzyme and there- 

 fore in the a-form, both retard the canesugar inversion to the same extent. /3-Glucose 

 therefore transmits the glucose rays (then perliaps converted into (3-gUicose rays) 

 quite as well as tlie :z-glucose. 



