PROCEEDINGS OF SECTION B. 119 



contain useful constituents not found in the oils richest in eucalyptol. 

 It is suggested that the standard for medicinal eucalyptus oils has 

 been fixed upon insufficient data. However, we have to accept the 

 standard as it is, and endeavour in the best way to supply the oils 

 demanded. 



When the oil of Eucalyptus globulus was first placed on the 

 market in commercial quantities, its constant nature and richness in 

 eucalyptol appealed to interested people in Europe, and commanded 

 more attention than did the pronounced terpene oils like that, for 

 instance, of Eucalyptus dives. At that time, however, the products 

 of only two species were recognised, viz., globulus oil and amygdaUna 

 oil. During later years the composition of the oils of over 150 distinct 

 species has been determined, from which it has been possible to 

 classify them into groups which yield oils in agreement ; these again 

 into sub-groups, from which the best species for oil production ce,n 

 readily be selected. " Globulus oil " has thus become practically a 

 name for the oils of a group, and, in the light of our present knowledge, 

 it would hardly be possible to distil oil from the leaves of Eucalyptus 

 globulus in sufficient quantity to compete with the better eucalyptol 

 oils of other species, better not only in yield but in eucalyptol content 

 also. Both Eucalyptus polybractea and Eucalyptus Smithii yield 

 more than twice the amount of oil obtainable from Eucalyptus 

 globulus, and the crude oils of both contain over 80 per cent, of 

 eucalyptol. The utilizatior of these more modern species has made 

 the working of such " Mallees " as Eucalyptus dumosa and Eucalyptus 

 oleosa less remunerative on account of the yield of oil obtainable from 

 these species being smaller, and it is the large yield of oil obtainable 

 from Eucalyptus cneorifolia of Kangaroo Island that enables this 

 species to still be profitably worked. 



The best species for oil distillation being now known, the question 

 of permanency naturally arises. The " Blue Mallee " Eucalyptus poly- 

 bractea grows over an extended area, and in country that is more and 

 more encroached upon each year for wheat-growing and other agri- 

 cultural purposes. It should not be difficult, by systematic treatment 

 and preservation of this species in its native habitat, together with 

 systematic planting, to establish large areas of this species alone, and 

 there seems little doubt but that, to a certain extent, it would be more 

 profitable to do this than to clear off the scrub and grow wheat. 

 Eucalyptus Smithii is somewhat sparsely distributed in the districts 

 where it occurs, so that it would be advisable to establish plantations 

 of this species from the beginning, as under natural conditions the 

 collection of the material is somewhat costly. The oil, however, obtained 

 from this species is probably the best of all the eucalyptol oils so far 

 determined, as it is as rich or richer in eucalyptol than any, and contains 

 objectionable constituents in minimum amount. The oil from the 



