SACCHARINE AND ASTKINGENT EXUDATIONS OF GREY GUM. 191] 
whole of the sugars in this exudation are fermentable under certain 
conditions, and it appears that the natural alteration of raffinose 
is exactly the same as when artificially treated. 
Ordinary Eucalyptus manna, as usually seen, is in small white 
opaque lumps. When in solution it reduces, to a small extent, an 
alkaline copper solution when heated, but when treated with acids 
a large quantity of reducing sugars are at once formed. As we 
have seen that tannic acid does not appear to exist in the sap 
circulating through the bark of Z. punctata, and as other acids 
are absent in this manna, we naturally expect to find the product _ 
fairly pure. Ordinary Eucalyptus manna is probably derived 
from punctures in the bark that have not penetrated into the cells 
of the tree containing tannic acid. In the darker saccharine 
exudation from £. pwnctata we find that tannic acid is present, 
and this probably accounts for the presence of the reducing sugars, 
these being derived from the crystallisable sugar by inversion, 
brought about probably by the presence of the tannic acid. The 
tannins of the Eucalypts tend to rapidly form anhydrides ; that 
such are present in this darker exudation is indicated by the dark - 
colour of the material, and the fact of its removal from the solution 
by hide-powder. The question arises, can we account for the 
presence of these sugars in this exudation, to the formation of 
anhydrides of the tannins by elimination of the molecules of 
water, when in combination with raffinose in natural solutions ? 
The darker saccharine exudation from EZ. punctata, therefore, 
contains :— 
Raffinose (melitose) 
Tannic acid and anhydrides. 
Eudesmin. 
Eucalyn (melibiose) 
And an easily fermentable reducing sugar. 
As levulose has been stated to be one of the products of the 
inversion of raffinose, it would be interesting to determine 
definitely whether that sugar is really present in the natural 
exudation from E. punctata, and next season if sufficient material 
, 
