BY B. GREIG-SMITH. 271 



amount, melted at 205° and was a glucosazone; the other, present 

 in very small amount, was galactosazone, and melted at 193°. 

 As the glucose might either be dextrose or levulose, the optical 

 activity was determined. The rotation of a solution of the 

 hydrolysed gum in a 200 mm. tube was + 0-9°. The sugar in 

 5 c.c. of this solution, when boiled with Fehling's solution, yielded 

 0862 grm. of copper, which is equivalent to 0-044 grm. or 0-88 % 

 of dextrose by Allihn's table. From these data the specific rota- 

 tion was [a] D = +51-14°. This closely agrees with the specific 

 rotation of dextrose, [a] D = +51-78°. As the relatively small pro- 

 portion of galactose present would have lowered the copper- 

 equivalent and therefore increased the specific rotation, it is 

 probable that the glucose was entirely dextrose. 



The optical activity of the gum was examined and was found 

 to be laevorotatory. The observed angle of rotation was - 0-98° 

 at 15° C, and as the solution contained 1 6875 % of total solids, 

 00710% of ash, and 00118% of nitrogen equal to 0-0737% of albu- 

 minoids, the specific rotation was — 0"98% x 100 or [ a J D = - 31-75°. 



1-543x2 

 A portion of the gum-jelly was hydrolysed by boiling with 5 % 

 sulphuric acid for five hours and made up to the original volume. 

 The acid solution gave a reading of + 1-72° in a 200 mm. tube. 

 Upon the assumption that the formula of the gum is C 6 H 10 5 

 and that it becomes entirely converted into sugars of the dextrose 

 formula, C 6 H 12 6 , there should have been in the solution 

 1-543 x i|~! or 1-714% of the hexoses. Calculating upon this, 

 the observed rotation was [a] D = +50-17, which shows that the 

 hydrolysis was complete and at the same time confirms the former 

 determination. 



A solution of the gum of the Lupin race contained - 922% of 

 total solids and gave a rotation in a 200 mm. tube of + 0-5°; after 

 inversion with sulphuric acid and reduction to volume the rota- 

 tion was + 0-9°. The direction of rotation of the gum thus 

 differed from the Macrozamia gum. On the assumption that the 

 gum contained 8-6 % of impurity (albuminoids and ash) as in the 

 former case, the specific rotation of the gum works out to 

 [ a ] D = +29-7° and the sugar derived therefrom to [a] p =+48*. 



