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a whitish opalescent emulsion nder the microscope (500) minute 
globules of an undissolved body (resin) are seen swimmin 
solution of the gum. Addition of caustic potash renders the opaque 
| 
spread ongn opal plate, changes its colour to a beautiful violet on 
caustic potash (after standing a while). By this reaction 
Grevillea robusta gum is easily recognised. Borax gelatimises the 
watery solution of arabic gum by being gelativised on addition of 
ferric chloride or ferric acetate, Sometimes this reaction takes place 
opposition to this a solution of Grevillea robusta gum is gelatin ‘ 
ferric salts only in the alkaline state, and the ferric gum compound 6 
precipitation. The purified gum does not give a violet reaction WH 
_ caustic potash, Resae actution of borax Sisken the watery solufion 
of the purified gum very stiff and sticky. me eS 
The resinous part of the gum resin is obtained on evaporalioy . 
— alcohol, by which the arabin has been precipitated. It 8. 
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beautifully violet, which colour, on addition of hydrochloric 80% 
- ‘ e i w. . . dent 
the resin contained in the resinous gum of Grevillea robusta W Bt 
They exuded pee Grevillea striata, and described fully 0D page 
bstanc a causes the bitter taste of the gum resid 
