________________________________________________________________________ | | | | | | Birch | Stones of | | |_____________|__________________________| | | | | | | | | | Bark | Wood | Date | Apricot | Peach | |_______________________________|______|______|________|_________|_______| | | | | | | | | Action of malt extract calcu- | | | | | | | lated as starch dissolved | 4.24 | 3.5 | 5.2 | 1.5 | -- | | | | | | | | | Residue boiled, 1 p.ct. HCl | | | Mannan | | | | gave pentosanes dissolved. | -- | -- | 11.7 | 14.1 | 6.7 | | | | | | | | | Residue yielded furfural | 19.3 | 17.8 | 3.4 | 9.6 | 9.7 | |_______________________________|______|______|________|_________|_______| The proportion of pentosanes (furfuroids) removed, i.e. hydrolysed by boiling with hydrochloric acid of 2.5 p.ct. HCl, is shown by the following estimations of furfural: _________________________________________________________________ | | | | | | | Birch | Sugar maple | | | |______________|_______________| Apricot | | | | | | | stones | | | Bark | Wood | Outer | Inner | | | | | | wood | wood | | |________________________|_______|______|_______|_______|_________| | | | | | | | | In original substance | 16.7 | 19.6 | 18.2 | 20.7 | 18.4 | | | | | | | | | In residue from action | 6.53 | 8.6 | 4.9 | 6.4 | 7.0 | | of 2.5 p.ct. HCl | | | | | | |________________________|_______|______|_______|_______|_________| _Wood Gum._--The paper contains some observations on the various methods of isolating this product. Attention is directed to the necessary impurity of the product, and to the fact that the numbers for furfural and for the xylose yielded by hydrolysis are considerably less than for a pure pentosane.