136 H. G. SMITH. 



On the CONSTITUENT of PEPPERMINT ODOUR occur- 

 ring in many EUCALYPTUS OILS.— Part I. 



By Henry G. Smith, p.c.s., Assistant Curator, Technological 

 Museum, Sydney. 



[Received and read before the Royal Society of N. 8. Wales, October 3, 1900.^\ 



Among the Eucalypts of Australia there are many species known 

 vernacularly as Peppermints, on account of the marked peppermint 

 odour given by the leaves when crushed, or from the odour of the 

 oil when distilled. 



The first Eucalyptus oil was obtained from a New South Wales' 

 species known as the Sydney Peppermint, Eucalyptus piperita, Sm., 

 which species grows plentifully in the neighbourhood of Sydney. 

 The following quotation is from page 227 of " White's Voyage to 

 New South Wales," published 1790 : — " The name of Peppermint 

 Tree has been given to this plant by Mr. White on account of 

 the very great resemblance between the essential oil drawn from 

 its leaves and that obtained from the peppermint, Mentha piperita, 

 which grows in England. This oil was found by Mr. White to be 

 much more efficaceous in removing all cholicky complaints than 

 that of the English peppermint, which he attributes to its being 

 less pungent and more aromatic. A quart of the oil has been 

 sent by him to Mr. Wilson." 



Although the leaves of this species have a well marked pepper- 

 mint odour, yet, the constituent giving this odour is only present 

 in very small quantity in the oil ; this is also the case with many 

 other species, the type E. amygdalina, for instance, which is also 

 known in some localities as peppermint. From our experiments 

 we find that this peppermint constituent occurs in greatest amount 

 in the oil obtained from the leaves of E. dives, next in that of 

 E. radiata, and in somewhat lesser amount from the leaves of 



