GUMS OF EUCALYPTS AND AXGOPHORAS. 



By JOSEPH LAUTERER, M.D. 



[Read before the Roijal Societi/ of Queensland, Februanj 7th, 1891.] 



The great demand of tannic acid and its relations in chemistry, 

 medicine, photography, tannery and many trades besides induced 

 me to examine once more the barks and gums of the Queens- 

 land Angophoras and Eucalypts, which contain a high percentage 

 of the said compounds. Ten years ago, one of our best medical 

 and scientific men. Dr. Joseph Bancroft, called the attention of 

 the chemists to the gums in question, and pointed out their 

 great usefulness for different purposes. The late well-reputed 

 chemist, Theodore Staiger, analysed for him the gums of 

 Eucalyptus maculata, resinifera, and tesselaris. Baron Mueller gives 

 some notes about the gums in his excellent Eucalyptographia, but 

 he did not investigate the matter himself. I would not tire you 

 with fresh notes on an old subject, if the reports given by the 

 various authors did not differ from each other in a very strange 

 way. Eucahjptus maculata, the " spotted gum " of the timber- 

 getters, yields a gum-resin in great quantities, exuding from 

 cracks and wounds through the inner bark. Baron Mueller says 

 that it dissolves entirely in hot water. All other writers state 

 the contrary, maintaining that it is only partly soluble in it. 

 Under certain restrictions Von Mueller might be said to be right, 

 because all the gum-resin of Eucalyptus maculata dissolves in 

 the water if boiled with it for a sufficient time, but, if you 



