459 



(a) For Pharmaceutical Purposes. - The species from which the first sample 

 of Eucalyptus oil had been distilled was E. piperita, and this Eucalypt gives a pro- 

 duct consisting of phellandrene, piperitone, cineol and some minor constituents. 



It is worthy of mention that the Eucalyptus oil industry was established 

 in Australia on oils of this class. It was in 1853 that Ba'ron von Mueller 

 recommended the. distillation of Eucalyptus oil, and he claims this in his "Extra 

 Tropical Plants," under E. amygdalina. In 1854 Mr. J. Bosisto established, in 

 Victoria, the first factory for the commercial distillation of Eucalyptus oil 

 in Australia, the species utilised being chiefly the one known at that time as 

 E. amygdalina. The oil of that species contained phellandrene, piperitone and 

 cineol, and in constitution had some resemblance to that of E. piperita. 



As the more pronounced cineol bearing Eucalyptus oils became in 

 request, those containing phellardrene receded in favour, and to meet this 

 demand the " Mallee " oils came into prominence, while in Tasmania the chief 

 species employed was E. globulns. The "Mallee" oils, being as a rule more 

 closely related to the " Boxes," have, in most cases, distinctive properties from 

 those of the E. globulus type, in that they contain the aldehyde aromadendral, a 

 constituent which has been shown by Dr. Cuthbert Hall and others to have five 

 or six times the bactericidal value of cineol. 



The demand at present for medicinal oils is mostly for those having a high 

 cineol content, and the United States Pharmacopoeia demands a minimum of 

 70 per cent, of that constituent ; but, as can be seen from the results recorded in 

 this work, only a comparatively few species yield oils of this character in 

 rufncient amount to be profitable for distilling at the usual price paid for cineol 

 oils, and for that reason the demand for those containing 70 to 80 per cent, 

 of cineol has, for some time past, far exceeded the -supply.* 



The British Pharmacopoeia's standard is more reasonable, only requiring 

 55 per cent, of cineol. For the supply of oils of this quality Australia has 

 numerous species, as can be seen by referring to the lists under Group III, 

 class (b\ and group IV, class (a). 



The question, however, is not yet settled as to whether cineol is the most 

 valuable medicinal constituent in Eucalyptus oils, and Dr. Attfield directs 

 attention to this uncertainty in his work on Chemistry (p. 505). Mr. E. M. 

 Holmes (Pharm. Journ. Ill, 25, p. 501) says that " the chemistry is far in 

 advance of the therapeutic and physiological knowledge of Eucalyptus oils." 



In connection with this question an investigation on the bactericidal value 

 of the several constituents of Eucalyptus oils was undertaken by Dr. Cuthbert 

 Hall, of Parramatta, in 1904; these results were published privately. 



Considerations respecting the therapeutic value of Eucalyptus oils are 

 beyond the scope of this work, but much information may be found scattered 

 throughout the various scientific and pharmaceutical publications. 



Such a large number of constituents occur in oils of the various Eucalypts, 

 that it may be the medicinal value of Eucalyptus oil is more largely due to the 

 admixture of certain of these, than to that of any one individual constituent. 



(b) For Mineral Separation.- A? with cineol, other constituents which 

 contain oxygen, such as citronellal, piperitone, aromadendral, geranyl-acetate, 

 &c., as well as the several terpenes, reach a maximum in the oils of particular 

 species of their class, and by taking advantage of this peculiarity, and exploiting 

 those species which contain the desired constituent in greatest abundance, these 

 products are now, or may eventually become, articles of commerce. 



* Commercially pure cineol is now manufactured in Australia, and can be supplied in any reasonable quantity if it is 



desired to use the pure product in preference to the oils. 



