475 



The species known as "Peppermint" on the island seems 

 to be closely related chemically to E . cneorifolia, and the oils 

 distilled from these two trees show great resemblances. The 

 principal constituent is cineol, and pinene is only present in 

 comparative small amount. The high-boiling aldehyde, 

 aromadendral, is a characteristic constituent in this oil, even 

 more so than in that of the ''Peppermint." The rectified oil 

 is slightly yellow in tint, as is usual with the oils of this 

 group. This colour is due to the influence of the particular- 

 phenol present. The product of this species is one of the 

 mcst pronounced cineol-bearing oils obtainable from the 

 whole genus, but requires rectification, so that the aromaden- 

 dral may be removed as much as possible. 



The average yield of oil was 1"8 per cent., but this may 

 be taken as the minimum yield, as the material was collected 

 in mid -winter. The crude oil was orange-brown in tint, and 

 had an odour similar to the ciueol-pinene oils of this group, 

 with a secondary odour of aromadendral. Volatile aldehydes 

 were present, but phellandrene was absent. 



The crude oil had specific gravity at 15° C.=0'9229; 

 rotation, a D — 3*3°; refractive index at 20° = 1'4664, and was 

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

 of this oil is largely due to the aromadendral. On rectifica- 

 tion a few drops of acid water with some aldehydes came over 

 below 174° (corr.). Between 174-185° C, 81 per cent, dis- 

 tille*d ; between 185-220°, 9 per cent, came over; and between 

 220-237°, 5 per cent, distilled. These fractions gave the 

 following results : — 



First fraction 

 Second fraction 

 Third fraction 



Sp. gr. at 15° C. I Rotation aj> 



0'9166 

 0*9172 

 0-9291 



- ri c 



- 4-r 



-16'2 C 



Eef. index at 20°. 



1-4632 

 1-4678 

 1-4866 



The high laevorotation of the third fraction is due to 

 the aromadendral. The cineol was determined by the 

 resorcinol method in the fractionated oil. When calculated 

 for the crude oil the result showed that 87 per cent, of 

 cineol was present. The saponification number for the esters 

 and free acids was 7*4. 



It will be noticed hew closely the above results agree 

 with those obtained with the oil distilled from the species 

 known vernacularly on Kangaroo Island as "Peppermint" 

 (E. odorata). 



