419 



The aliphatic paraffins cannot be considered as very rare constituents in 

 essential oils, as their presence has been shown in those of more than a dozen 

 different plants. Essential oils containing paraffin in greatest amount are Rose 

 oil and Chamomile oil, and in these the stearoptene is often so abundant that 

 the oil congeals on cooling. The paraffin recorded from Neroli oil melts at 

 exactly the same temperature as that from the oil of E. acervula, while that in 

 Chamomile oil only differs by one degree. No less than eight paraffins have 

 been recorded from other essential oils, the melting points of which are within 

 one degree of that isolated from the oil of E. Smithii. 



It is perhaps worthy of remark that the first paraffin isolated from the 

 Eucalypts was from the oil of a species (E. acervula} which contains a 

 considerable amount of geraniol, a constituent also present in Rose oil. On the 

 other hand the oil of E. Macarthuri, which has a very large amount of 

 geraniol, does not appear to contain it. That the paraffin was derived from the 

 leaf oils of E. acervula and E. Smithii is evident from the fact that these species 

 were not in bloom when the oil was distilled. 



Methods of Preparation. Portions of the crude oils of two consignments 

 of E. acervula were dissolved in a large excess of 80 per cent, alcohol, when 

 a copious, flocculent substance separated. The precipitate was filtered off, 

 using a hardened filter, washed with alcohol, and the solid fat-like substance 

 melted on the water bath to separate adhering water and alcohol. The amount 

 of crude material thus obtained from the oil of one sample was equal to 0-76 

 per cent., and from the other 0-82 per cent. This method, however, was 

 somewhat wasteful. The crude oil was then distilled, when the portion boiling 

 above 280 C. became semi-solid when cold ; this was boiled in alcohol, filtered 

 hot, cooled, and the process repeated. After standing some time the precipitate 

 was filtered off and boiled in acetic ether, which was found to be a good solvent 

 for the purpose, as the paraffin was little soluble in the cold. On cooling, the 

 substance separated, most of the impurities remaining in solution. The semi- 

 crystalline paraffin was then boiled in alcohol, a little animal charcoal added, 

 and filtered hot. It was finally dissolved in chloroform and precipitated by the 

 addition of alcohol. When thus obtained it differed in no respect from the 

 corresponding material precipitated directly from the crude oil by alcohol. 



The paraffin was separated from the oil of E. Smithii by steam distilling 

 the oil until the greater portion had come over, and treating the residue with 

 cold 80 per cent, alcohol, when the paraffin was precipitated. It was then 

 purified in a similar manner to that of E. acervula. 



The Deposit which forms in the Oils of some 

 Species of Eucalyptus. 



THE oils of certain Eucalypts, when freshly distilled, contain a constituent which 

 slowly changes its character and eventually deposits an insoluble precipitate. 

 This constituent is never present in great quantity, and in some instances only in 

 traces. In the majority of species it is absent, and appears to follow the general 

 rule of all Eucalyptus oil constituents, in increasing in amount through a range 

 of species until a maximum is reached in one or more of them. 



