TWO CHEMICAL CONSTITUENTS FROM THE EUCALYPTS. 65 



On acetylation, the ester content was found to be 82'2f°, 

 whereas the crude oil only gave 80*5°/° of ester on acetyla- 

 tion, thus indicating that the greater portion of the free 

 alcoholic bodies had been recovered in the rectification. 



In an interesting series of experiments carried out by 

 MM. Oharabot and Hebert, " on the mechanism of esteri- 

 fication in plants," and published in the Scientific and 

 Industrial Bulletin of Roure-Bertrand Pils of Grasse, Oct. 

 1901, it is shown that the maximum ester content obtained 

 with geraniol and acetic acid, by the method of experiment 

 adopted, was reached when the cm ^Tjl™T equalled fft-, but 

 it is rarely that this ratio in the naturally obtained oil 

 from E. Macarthuri falls below -any. This high ester con- 

 tent for naturally combined geraniol, is another instance 

 of the exceedingly interesting nature of the problems sub- 

 mitted by the members of this wonderful genus, because 

 if the process of esterification of the terpene alcohols takes 

 place in the chlorophyll bearing organs as supposed, it seems 

 somewhat remarkable that in no other species of Eucalyptus 

 so far investigated, has this ester been detected in quantity, 

 and the appearance of the tree of E. Macarthuri is a typi- 

 cal Eucalyptus, in its suckers, its bark, its leaves, its 

 buds, and its fruits, and the constituents of its oil are 

 always of the same character. Nor is it the presence of 

 an increasing amount of acetic acid in the oil of this species 

 that is answerable for the formation of this ester, because 

 in the oils of some species (E. umbra particularly) a large 

 amount of acetic acid is present in combination as an ester, 

 but the alcohol is not geraniol. With the exception that 

 E. Macarthuri belongs to the same natural order as Dar- 

 winia fascicularis, i.e., the Myrtaceae, there is little 

 resemblance between these two plants, but the oils obtained 

 from them are almost identical as regards the ester. II 

 then the esterification in plants is brought about by the 



E— July 2, 1902. 



