473 



The origin of the name ' 'Peppermint' ' for this species 

 could not be traced, and it seems to be altogether a misnomer, 

 as the ketone of peppermint odour (piperitone) appears to be 

 absent in the oil, the characterstic high-boiling constituent 

 being aromadendral. The name "Peppermint" is also given 

 to Eucalyptus species in New South Wales, the oils of which 

 do not contain piperitone, nor do their oils have a peppermint 

 odour. The oils of the true "Peppermint" Eucalyptus species 

 contain the terpene phellandrene, in addition to the pepper- 

 mint ketone. 



The average yield of oil was 1*87 per cent., but as the 

 material was collected in the winter this may be taken as the 

 minimum yield. The crude oil was orange-brown in tint, 

 indicating but a trace of phenol, and had an odour similar 

 to those belonging to the cineol-pinene group, with a 

 secondary odour indicating aromadendral. Volatile alde- 

 hydes were pronounced. The oil was very rich in cineol, and 

 phellandrene was absent. 



The crude oil had specific gravity at 15° C. =0 9193; 

 rotation a D — 1'1°; refractive index at 20° = 1*4639, and was. 

 soluble in 1\ volumes 70 per cent, alcohol. The laevorotation 

 shown by this oil is due to the aromadendral. The saponifi- 

 cation number for the esters and free acids was 8'5. 



On rectification a. few drops of acid water with some 

 aldehydes came over below 173° C. (corr.), showing the com- 

 parative absence of the lower-boiling terpenes. Between 

 173-185°, 82 per cent, distilled; between 185-215°, 8 per 

 cent, came over, and between 215-230°, 4 per cent, distilled. 

 These fractions gave the following results: — 



First fraction 

 Second fraction 

 Third fraction 



Sp. gr. at 15° C. 



0-9153 

 0'9161 

 0-9219 



Eolation aj) 



o-i° 



0'7° 

 11-7° 



Ref. index at 20°. 



1-4619 

 1-4639 

 1-4794 



The high laevorotation of the third fraction is due to the- 

 aromadendral. The cineol was determined by the resorcinol 

 method in the fractions distilling below 185°. The results 

 from two determinations showed that 86 per cent, of cineol 

 was present in the crude oil, which proves it to be one of the 

 richest ciiieol-bearing oils of the whole group. 



The rectified oil was slightly yellow in tint, due to the- 

 particular phenol present. 



