69 • 



ON THE MEDICINAL PROPERTIES OF THE RED GUM OF 

 AUSTRALIA. 



BY JAMES SUTHERLAND, M.D. 



The accompanying gum, a most invaluable medicine in certain 

 disorders, is the produce of the Eucalyptus rostrata, a tree of frequent 

 occurrence in the colony of Victoria and many parts of Australia. 

 It exudes in a fluid state from the bark, and in many instances 

 between the different layers of the wood, in the months of November, 

 December, January, February, and March, and by the evaporation of the 

 watery particles by which it is held in solution ; it concretes into a beau- 

 tiful ruby-coloured gum which, when exposed for a length of time to the 

 air and the sun, assumes a black colour from an imperfect oxidation, losing 

 at the same time its astringency. It is the only known vegetable astrin- 

 gent with the exception of the wattle gum which exudes in this state 

 — for the kino and catechu, though called gums, are really extracts, being 

 obtained by evaporating a decoction of the smaller twigs and branches of 

 the Acacia Catechu, and the Pterocarpus Erinacea, and possess no muci- 

 laginous properties. The S. G. varies from T25 to T35. It has a highly 

 astringent taste, much more so than tannin or gallic acid. It is soluble 

 in water almost in any quantity, for when added greatly in excess to that 

 fluid it softens, and forms a semifluid mass of the consistence of honey, or 

 thick mucilage. It is also soluble in alcohol, though not to the same 

 extent as in water. When digested in sulphuric ether for some days a 

 small quantity is dissolved, forming a deep red solution. According to 

 my experiments one fluid ounce of ether dissolves six grains. It dissolves 

 speedily in nitric ether, forming a beautiful dark-red tincture, though 

 its astringency is rather impaired in this menstruum. It is alto- 

 gether insoluble in chloroform, in which it floats upon the surface, and 

 is neither softened by nor miscible with it. It strikes a deep black 

 colour with the tincture of steel and sulphate of iron, and causes white 

 flocculent precipitates, with solutions of animal gelatine, albumen, alum, 

 sulphate of zinc, corrosive sublimate, muriate of morphia, sulphate of 

 copper, hydrodate of potash, and carbonate of soda. With the bichro- 

 mate of potash it yields a copious dark-brown, curdy precipitate, quite 

 different from that occasioned by tannin. Nitrate of silver occasions a dark 

 precipitate almost approaching to black. When treated with lime water, 

 it assumes a dark hue, and gradually a pale-brown, gelatinous precipitate 

 ensues. With the caustic alkalies it forms dark yellow solutions, and an 

 orange-coloured solution with the tincture of iodine. Sulphuric acid 

 throws down a brown-coloured, flocculent precipitate — nitric acid has no 

 perceptible action at all — while the muriatic precipitates only a few and 

 new coloured flocculi. 



These experiments show that this gum is an original astringent prin- 



