SACCHARINE AND ASTRINGENT EXUDATIONS OF GREY GuM. 185 
investigation was needed, as it differs but little from the Eucalyptus 
manna already worked out. The principal sugar was found to be 
identical in both the white and dark exudations, and as the latter 
was a compound of substances, its investigation might, I thought, 
lead to valuable results. I am not aware of any previous research 
on these exudations from Z. pwnctata, nor on like material to this 
dark exudation from any of the Eucalypts. 
After preliminary tests as to the best method of proceeding I 
adopted the following :—The material was heated with 80% alcohol, 
the whole of the sugary portions were thus dissolved with other 
substances. A rather large quantity of debris was left on filter- 
ing, consisting of fragments of bark and wood, indicating that 
portions of the bark had been eaten. The filtrate was evaporated 
to a pasty consistence, and absolute alcohol added. A whitish 
gelatinous precipitate was thus obtained ; the very dark filtrate 
was set aside for further investigation, and the precipitate pressed, 
boiled in and washed with fresh alcohol. The precipitate was 
then dissolved in alcohol sufficiently dilute to dissolve the pasty 
mass, and set aside to crystallise. It took some days before 
crystals commenced to form, when they appeared in small nodular 
masses, which continued to increase until the material became 
quite granular. These crystals were washed with strong alcohol, 
filtered, dried on a porous slab, repeatedly crystallised and treated 
in the same way until the dilute alcohol ceased to be appreciably 
coloured when the crystals were redissolved in it. They were 
finally dissolved in water, alumina added, filtered, evaporated 
down at low heat on water-bath and allowed to crystallise, the 
liquid being perfectly clear and colourless. If sufficiently reerys- 
tallised from dilute alcohol, and the crystals drained on the slab 
repeatedly, the raffinose thus prepared, when crystallised from 
water, does not reduce Fehling’s solution to any degree on boiling — 
before being inverted. Although it was difficult to obtain the 
crystals when the solution was so impure, the sugar often taking 
days to crystallise, yet, as the crystals became purer they were 
obtained much more rapidly. The material thus obtained was 
