BY U. GREIG SMITH. 



327 



It is clear that a considerable elevation of the germicidal 

 activity had, in course of time, resulted from the acidification. 

 It was tested on the 108th day after acidification. The acidity 

 of the oil would have little effect in acidifying the dilutions, for 

 at 1 : 400 the acidity would be less than 25°. The experiment 

 therefore shows that acidification does, in time, cause the oil 

 of E. cinerea to become more germicidal, and since storage of 

 the oil results in the natural development of acidity, it follows 

 that storage of the oil, by reason of the formation of acids, will 

 lead to the production of germicidal substances. It will in pro- 

 gress of time become more and more bactericidal. 



The Oils of E. australiana. — The oils of this member of 

 the Peppermint group of Eucalypts differ according to 

 whether the trees grow on the high ridges of the Main 

 Dividing Range or at lower elevations. The oil from the 

 latter is termed E. australiana. and that from the ridges is 

 named E. australiana, Braid wood. E. australiana contains some 

 70% of cineol, while the Braidwood oil has about half this 

 amount replaced by phellandrene. Otherwise the constituents 

 are much the same. Besides the cineol, the oil of E. australiana 

 contains a little piperitone, occasionally a little phellandrene, a 

 phenol (Tasmanol), a small amount of esters, and some of an 

 unknown alcohol. The oil is not generally rectified, but, in dis- 

 tilling the leaves, the oil that comes over during the first hour 

 is sufficientlv pure to enable it to be sold for medicinal purposes. 

 It is known as " First Huur Oil," and contains over 70% of 

 cineol and usually but a trace of phellandrene and a minimum 

 amount of volatile aldehydes.* 



* Proc. Roy. Soc. N. 8. Wales, 1915, 514. 



