ESSENTIAL OIL OF EUCALYPTUS SMITHII. 165 



The optical activity of the eudesmol, which occurs in the 

 oil of this species, was determined in the product from a three 

 year old cultivated tree growing at Marrickville. Usually 

 this stearoptene is present in very small amount, particu- 

 larly in commercial samples, and the higher dextrorotation 

 of the crude oil, over that of the rectified, indicated the 

 presence of an active substance in the portion boiling above 

 190° O., and as eudesmol appeared to be the chief con- 

 stituent in the residue it was isolated and purified. 0*2146 

 gram, in 10 cc. alcohol rotated the ray 0*85 degrees to the 

 right, the specific rotation of this sample of eudesmol was, 

 therefore, [a] D — + 39*6°. 



It will be interesting to determine whether the difference 

 in optical activity between eudesmol from the non-phellan- 

 drene oils, and that from the phellandrene bearing ones is 

 of a constant character with all the species of the several 

 groups. There is much work yet required to be done in 

 order to determine the chemistry of this peculiar con- 

 stituent, of not uncommon occurrence in Eucalyptus oils. 



The comparative absence of constituents in the oil of this 

 species which might be considered of an objectionable 

 nature, suggested the desirability of adopting other methods 

 for the rectification of the crude oil than that of redistilla- 

 tion or steam distillation. The following method answers 

 admirably for this purpose. When the crude oil was shaken 

 repeatedly for some hours with very dilute sulphuric acid, 

 the reddish colour — due to the presence of a small amount 

 of iron from the still acting on the phenol — was removed. 

 The oil was well washed and dried by agitating with per- 

 fectly dry carbonate of soda. The product thus obtained 

 was usually tinged yellow and had all the brilliancy of the 

 oil when redistilled, besides retaining the small amount of 

 phenol and traces of other constituents which may, perhaps, 

 be found eventually to add therapeutic value to an oil of 



