94 H. G. SMITH. 



and that it is isomeric with ordinary camphor, but has no 

 rotation. 



Eucalyptus globulus belongs to a group of Eucalypts, of which 

 we have several in this colony, the oils of which have great resem- 

 blance to each other and when distilled are always rich in 

 eucalyptol, they contain dextropinene in varying quantities and 

 are free from phellandrene. In this group the alteration of the 

 constituents through eudesmol to eucalyptol is rapid and but little 

 reserve material of high boiling constituents is stored in the leaf, 

 although both in the case of E. goniocalyx and E. Smithii eudesmol 

 was found. It is probable for this reason that phellandrene is 

 found to be always absent in the oils of the globulus group, which 

 on distillation appear to generally contain nearly their maximum 

 amount of eucalyptol, and therefore undergo little alteration on 

 keeping. In those oils like E, macrorhyncha, E. piperita, E. 

 eugeviioides, etc., which contain a fair percentage of eucalyptol, 

 and mostly some phellandrene, the change is not usually completed 

 at time of distillation, and we can thus trace the process of alter- 

 ation of the constituents and the formation of the ultimate product, 

 eucalyptol. 1 In the redistillation of those oils under atmospheric 

 pressure, besides the water always given off at about 100° C, it is 

 found that water is again always split off from the constituents 

 boiling at a high temperature particularly that fraction containing 

 eudesmol. The constitution of eudesmol indicates that the oxygen 

 atom is attached to the molecule previous to the formation of 

 eucalyptol. Which particular terpene is necessary to this forma- 

 tion of eucalyptol is uncertain, but phellandrene cannot be detected 

 when the apparent maximum of alteration has taken place. It is 

 found that the pinene present in the oils of the group of Eucalypts 

 to which E. macrorhyncha belongs is always laevopinene, whereas 

 in the oils of the globulus group the pinene always appears to be 

 dextropinene, and the indication thus is that it is the laevo-terpenes 



1 In this paper I have not dealt with that group of Eucalypts whose 

 oils consist very largely of phellandrene, nor those whose oils consist- 

 very largely of pinene. 





