198 H. G. SMITH. 



The late Baron von Mueller, whose knowledge of the Eucalypts 

 of Australia was unique, recognised years ago, the possible assist- 

 ance the botanist might derive in determining differences in species 

 by the results of chemical investigation of their constituents. The 

 reference is so important in connection with the results brought 

 forward in this paper, that I indicate the paragraph, published 

 by the Baron in 1879. 1 



" E. obliqua is distinguished from E. piperita by . . . and 

 perhaps by anatomic, histologic, and chemical peculiarieties of 

 the bark and wood which characteristics remain yet more com- 

 prehensively to be studied" The italics are mine. 



Since that time much has been done in determining the chemical 

 characteristics of several of the species. The results of the 

 present research not only assisted in finally determining the 

 species, but present possibilities of commercial value in deter- 

 mining the utility or otherwise of the products of the tree by the 

 determination of its chemical constituents. According to Mr. 

 Baker, the Rylstone specimen (E. Icevopinea) has certain botanical 

 affinities with those of E. macrorhyncha, but chemically these 

 two trees are quite distinct, and the importance of this is apparent 

 when it is stated that the leaves of E. Icevopinea do not contain 

 myrticolorin like those of E. macrorhyncha, nor does the oil con- 

 tain eudesmol and other constituents found in the oil of E. mac- 

 rorhyncha. 



The presence of a pinene in the oil from E. globulus was detected 

 some time ago. M. Cloez in 1870 2 published the first detailed 

 observations relative to the oil of E. globulus. This research is 

 now of historic interest from the fact that he obtained a hydrocarbon 

 C 10 H 16 boiling at 165° C, by distilling his so-called eucalyptol with 

 P 2 5 . This terpene he called eucalyptene. Afterwards Faust 

 and Homeyer 3 gave the same name to a terpene from Eucalyptus 

 oil which according to them is a terebenthene, being readily poly- 

 merised by sulphuric acid. Later, Wallach and Gildmeister 4 



1 Eucalyptographia, Decade in., Art. Eucalyptus piperita. 



2 Compt. rend. 1870, 687 and Journ. de Pharm. and Chimie 1870, xn. 201. 



3 Ber. 7, 63, 1429. * Ann. 246, 265 - 284. Abst. Chem. Soc. 1888, 54, 1205. 



