320 



Prof. Dunstan and Drs. Henry and Auld. 

 Series 1. — Temperature, 39° C. 



[Feb. 27, 



Time 

 of action. 



Initial rotation. 



Rotation after 



addition 

 of ammonia. 



Change 

 in rotation. 



hours. 

 

 1 

 2 

 3 

 20 



o / 



-1 15 



-0 46 

 -0 35 

 -0 34 

 -0 56 



-1 15* 

 -1 11 



-0 58 

 -0 57 

 -0 56 



6 

 -0 25 

 -0 23 

 -0 23 







* The non-occurrence of any immediate change in rotation indicates that the optical rotation 

 of phaseolunatin is not affected by the addition of the minute quantity of alkali necessary in 

 carrying out these experiments. 



In this series of experiments 2*85 grammes of phaseolunatin were dissolved 

 in 20 c.c. of water, and to the solution 0*5 gramme of the enzyme preparation 

 was added. 



Series 2. — Temperature, 40° C. 



Time 

 of action. 



Initial rotation. 



Rotation after 



addition 

 of ammonia. 



Change 

 in rotation. 



hours. 



o-o 



0-5 

 1-5 



3-0 

 20-0 



o / 



-1 



-0 44 

 -0 38 

 -0 29 

 -0 50 



O ' 



-1 

 -0 59 

 -0 55 

 -0 50 

 -0 50 



o / 





 -0 15 

 -0 17 

 -0 21 







The various portions of the liquid resulting from these two series of 

 experiments were mixed and boiled with dilute sulphuric acid to ensure 

 complete decomposition of the glucoside. The acid liquid was then 

 neutralised with barium carbonate, evaporated to dryness on the water bath, 

 and the residue extracted with strong alcohol. This extract was then 

 decolourised with animal charcoal, and the contained sugar precipitated by 

 adding excess of ether. The sticky precipitate was dissolved in diluted 

 alcohol, from which on standing the sugar separated in the form of minute 

 colourless plates, melting at 85°, which is the melting point of dextrose. It 

 had, moreover, the same specific rotation as dextrose. It was shown in the 

 previous paper* that the sugar produced by the hydrolysis of phaseolunatin 

 is dextro-rotatory, and yields a phenylglucosazone, melting at 208°. The sugar 

 produced by the hydrolysis of phaseolunatin is therefore dextrose. 

 * Dunstan and Henry, 'Eoy. Soc. Proc.,' 1903, vol. 72, p. 285. 



