120 R. T. BAKER AND H. G. SMITH. 



whose oils contain phellandrene and the ketone of peppermint 

 taste and odour, and the presence of which constituent in the oil 

 gives the name of "peppermints" to so many of our Eucalyptus 

 trees. The principal terpene present in the oils obtained from 

 species whose leaves have this venation is (with but one or two 

 exceptions) phellandrene. 



That it is possible to find species with this venation in which 

 this terpene could not be detected is not to be wondered at, 

 because the constituents found in Eucalyptus oils are present in 

 varying proportions in the oils of the several species belonging to 

 the several groups and pass over into the members of the other 

 groups, and of course we find other species connecting the several 

 groups together. It is thus that we find some oils rich in 

 phellandrene and in which it is difficult to detect the peppermint 

 constituent although it is not possible to decide with absolute 

 certainty when a particular constituent is quite absent from any 

 Eucalyptus oil. 



It is, too, this closely related connection between numerous 

 allied species, this gradation from one member to another, that 

 makes the botanical study of the Eucalyptus so perplexing. The 

 particular venation to which we are now referring is that which 

 is seen in the leaves of E. coriacea, E. Sieberiana, E. vitrea, E. 

 dives, E. radiata, E. amygdalina, E. delegatensis, E. oreades and 

 many others. All the oils from these species contain phellandrene 

 in varying amount, they all contain more or less of the peppermint 

 ketone, while in some of them eucalyptol occurs, varying from traces 

 in some species up to 20 or 30 per cent, in others. This group also 

 contains the species (E. piperita) from which the first Eucalyptus 

 oil was obtained. This was distilled by Dr. White in 1788, and 

 owing to the presence of the peppermint constituent in the oil he 

 gave the name of "Peppermint" to the tree, thus the first 

 Eucalyptus species from this State received both its vernacular 

 and specific names on account of the presence of a particular 

 chemical constituent in its oil, what we have done in these 

 researches is simply to amplify the earlier results of this chemical 



